Methanol decomposition catalysts incorporating manganese, and methods of making and using such catalysts

Abstract

The present application discloses methods of decomposing methanol into carbon monoxide and hydrogen The method involves contacting methanol with a methanol decomposition catalyst to decompose at least a portion of the methanol to form H2 and CO, the methanol decomposition catalyst comprising manganese and at least one further metal, wherein the methanol decomposition catalyst does not comprise copper. Also disclosed are a process for performing an integrated Fisher-Tropsch synthesis using the products of the methanol decomposition as a feed stream.

Description

METHANOL DECOMPOSITION CATALYSTS INCORPORATING MANGANESE, AND METHODS OF MAKING AND USING SUCH CATALYSTSFIELD OF THE INVENTIONThe present invention relates to methods for decomposing methanol into hydrogen and carbon monoxide, and to catalysts suitable for use in such methods.BACKGROUNDMethanol has great promise as a renewable feedstock for a range of industrial processes. It is a common and inexpensive commodity chemical which may be produced from numerous sources, including fermentation, biomass pyrolysis, catalytic reaction of syngas, and CO2 hydrogenation. Advantageously, it is a liquid at ambient temperatures and pressures, allowing it to be transported through low-pressure pipelines, ships, or trucks, and thus generally allows for increased transportation efficiency as a liquid.Methanol holds especially great promise as a hydrogen carrier since it holds the highest hydrogen to carbon ratio of any liquid fuel and is much easier to store and transport than hydrogen itself.One option for unlocking hydrogen from methanol is steam reforming, which produces hydrogen and carbon dioxide. Whilst carbon dioxide in itself can serve as a feedstock for other processes, a potentially more attractive route is to decompose methanol into hydrogen and carbon monoxide (i.e. syngas) through use of a suitable catalyst. The hydrogen or syngas produced from methanol decomposition has the potential to be used for a wide range of purposes, including interfacing with other industrial processes such as the Fischer-Tropsch production of hydrocarbons (as explored in the applicant’s earlier application WO 2024 / 033867).Catalysed methanol decomposition has been disclosed in the art, such as in US 4,716,859, US 6,541 ,142 and US 9,833,773, Usami, et al., “Catalytic methanol decomposition at low temperatures over palladium supported on metal oxides.” Appl. Cat. A 171 (1 ): 123-130 (1998), and in Hargreaves, J.S.J. and Ormsby, G. Catalysis 2007, 20. 107-121. However, information on how to optimise such decomposition reactions to achieve high productivity and / or selectivity, and to allow the reaction to interface with other processes and applications, is relatively limited. Given the potential of methanol to serve as a key driver for the adoption and scaling of green technologies, there is a need to develop methods and materials which tailor methanol decomposition to suit specific industrial uses.The present invention has been devised in light of the above considerations.SUMMARY OF THE INVENTIONThe invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided.In WO 2024 / 033867, the present applicant discusses a Fischer-Tropsch process using syngas generated by a preceding methanol decomposition step. The most preferred methanol decomposition catalyst discussed in the document is a copper / zinc oxide catalyst (see e.g. paragraphs

[0022] and

[0081] ). Such catalysts are commercially available (for example, the T-2130 catalyst available from Sud-Chemie) and are known to be effective catalysts for producing methanol from syngas. It was predicted that such copper / zinc oxide catalysts would also be good candidates for catalysing the decomposition of methanol to syngas, based on the principle of microscopic reversibility.The present inventors have now discovered a means to boost the performance of methanol decomposition catalysts, allowing them to outperform other known methanol decomposition catalysts such as copper / zinc oxide catalysts. Specifically, the inventors have discovered that the methanol decomposition performance of a metal can be boosted by the addition of manganese, allowing effective operation at relatively low temperatures.Thus, in a first aspect, the present invention provides a method of decomposing methanol, the method comprising contacting a methanol decomposition catalyst with a feed stream comprising methanol to decompose at least a portion of the methanol to form H2and CO, the methanol decomposition catalyst comprising manganese and at least one further metal, wherein the methanol decomposition catalyst does not comprise copper.The performance enhancement provided by manganese was unexpected. Manganese is not specifically mentioned as a suitable material to incorporate in a methanol decomposition catalyst in WO 2024 / 033867. An overview of methanol decomposition is provided in the review article Hargreaves, J.S.J. and Ormsby, G. Catalysis 2007, 20. 107-121 (henceforth “Hargreaves”). The review provides a long list of methanol decomposition catalysts used in previous studies, of which only six contain manganese. These catalysts are all based around copper with chromium or zinc. The relevant studies summarised in Hargreaves which report use of manganese are Cheng, W.H. et al. Appl. Catal. A.: Gen., 1995, 130, 13 (referred to henceforth as “Cheng 1 ”), Cheng, W.H. et al. Appl. Catal. A.: Gen., 1998, 170, 215 (referred to henceforth as “Cheng 2”), Xi, J. and Lu, G. Appl. Catal. A.: Gen., 2002, 225, 77 (henceforth Xi et al.) and Cheng, W.H. Appl. Catal. B.: Environ., 1995, 7, 127 (henceforth referred to as Cheng 3). Cheng 1 is concerned exclusively with copper-based catalysts, examining the effect of adding further elements on performance. The document notes deactivation issues with some copper catalysts. Cheng 2 looks at the effect of adding Li, Na and K to the methanol decomposition effect of a commercially available catalyst containing Cu / Cr / Mn in the weight ratio 39 / 37 / 3 - G-89 catalyst from Nissan Girdler Catalyst, which was sold as a catalyst foraldehyde or ketone hydrogenation. The role of Mn itself on methanol decomposition is not explored in Cheng 2 - the effect of the metal content of the catalyst is not studied, only the effect of Li, Na and K. Xi et al. study copper / zinc catalysts, trying to fix problems with poor activity and deactivation over time through incorporating nickel (see the abstract and introduction). Cheng 3 also points to a potential weakness of copper catalysts (including Cu / Cr- based catalysts), noting slow deactivation of catalyst activity (see abstract of Cheng 3). The authors indicate that these deactivated catalysts can be regenerated by treatment in O2 containing atmosphere followed by reduction in hydrogen. JP 2003-093879 A discloses catalysts for decomposing methanol. While it is suggested that their catalyst precursor can contain additional elements, no advantage associated with manganese is reported. A. Mosayebi (Research on Chemical Intermediates (2021 ) 47:2951 -2972) discloses kinetic modelling and experimental investigations of dry reforming of methanol over a specific catalyst.At a commercial scale, deactivation of copper catalysts over time represents a challenge since it is unfeasible to carry out regular regeneration or catalyst replacement steps. Thus, the discovery by the present inventors that manganese can be used to boost the performance of other metals represents a significant contribution to the art.Preferably, the further metal is or comprises nickel, palladium, or platinum. In a preferred implementation, the at least one further metal comprises nickel. In especially preferred implementations, the one further metal is nickel alone. The present inventors have found that manganese provides a particularly effective boost in performance for nickel-based catalysts, as demonstrated in the examples below. This was particularly surprising, since the use of nickel- based catalysts for methanol decomposition has not been reported extensively, as noted by the one example of a nickel-containing catalyst in Table 2 of Hargreaves, J.S.J. and Ormsby, G. Catalysis 2007, 20. 107-121.In view of the advantages of using manganese alongside nickel, a further aspect of the present invention also provides a method of decomposing methanol, the method comprising contacting methanol with a methanol decomposition catalyst to decompose at least a portion of the methanol to form H2 and CO, the methanol decomposition catalyst comprising manganese and at least one further metal, the at least one further metal comprising nickel (and optionally including copper).Preferably, the manganese is present in an amount in the range 0.05 to 10% by weight of the methanol decomposition catalyst, based on the total weight of the methanol decomposition catalyst. Amounts between 4-10 wt.% may be particularly preferred, such as 4.5-10 wt.% or 5- 10 wt.%.Preferably, the at least one further metal is present in an amount up to 10% by weight of the methanol decomposition catalyst, based on the total weight of the methanol decomposition catalyst.Preferably, the total amount of the manganese and the at least one further metal is up to 20% by weight of the methanol decomposition catalyst, based on the total weight of the methanol decomposition catalyst.Preferably, the manganese and the at least one further metal are supported on a support. The support may be selected from, for example, zirconia, alumina, ceria, silica and titania, or a mixed oxide comprising a mixture of two or more of zirconia, alumina, ceria, silica and titania. Preferably, the support is or comprises zirconia, titania or alumina, most preferably the support is zirconia.Also provided herein is a method of preparing a methanol decomposition catalyst comprising manganese and at least one further metal, the method comprising: impregnating a support material with:(i) a solution containing a manganese compound, and(ii) a solution containing a catalyst-precursor compound comprising the at least one further metal (other than manganese), to form an impregnated support material drying and calcining the impregnated support material to from the methanol decomposition catalyst, optionally, wherein the at least one further metal comprises at least one of nickel, palladium and platinum; further optionally, wherein the at least one further metal is not copper.Accordingly, also provided herein is use of a methanol decomposition catalyst prepared by the method above, in a method of decomposing methanol according to the first aspect of the invention.Accordingly, also provided herein is use of a methanol decomposition catalyst prepared by the method above, to increase methanol conversion and / or to increase CO productivity, in a method of decomposing methanol.Also provided herein is use of manganese in a methanol decomposition catalyst for improving the performance of the methanol decomposition catalyst. In some examples, the improvement may be relative to an identical methanol decomposition catalyst not comprising manganese. In some examples, the improvement may include increased methanol conversion and / or increased CO productivity. In some examples, the improvement may be at relatively low temperatures, such as at 200-500°C, such as 200-450°C, or 200-400°C, or 200-350°C, or 200-300°C, or 250-500°C, or 250-450°C, or 250-400°C, or 250-300°C, or 300-500°C, or 300-450°C, or 300- 400°C.In a further aspect, the present invention provides use of a methanol decomposition catalyst as described for the first aspect, to improve methanol decomposition during a method of decomposing methanol. In some examples, the improvement may be relative to a copper zinc oxide catalyst, particularly a copper zinc oxide catalyst having the composition: 33 wt.% CuO and 66 wt.% ZnO, such as T-2130, available from Sud Chemie. In some examples, the improvement may include increased methanol conversion and / or increased CO productivity. In some particular examples, the improvement may include increased methanol conversion and / or increased CO productivity relative to the copper zinc oxide catalyst mentioned. In some examples, the method of decomposing methanol may be a method according to the first aspect.In a further aspect, the present invention provides a process for performing an integrated Fisher-Tropsch synthesis, the process comprising: providing a first feed stream comprising methanol; contacting the first feed stream with a methanol decomposition catalyst comprising manganese to decompose at least a portion of the methanol to form a first product stream comprising H2and CO in a method according to the first aspect of the invention; optionally providing a second feed stream comprising H2and at least a portion of the CO of the first product stream; and contacting the first product stream or, optionally, the second feed stream, with a Fischer- Tropsch catalyst to perform a Fischer-Tropsch synthesis to provide a second product stream comprising Cs+ hydrocarbons.A further aspect of the invention provides a methanol decomposition catalyst as defined herein. The methanol decomposition catalyst may be, for example, a combination of nickel and manganese provided on a support, in particular a zirconia support.As used herein, a “feed stream” is used to mean the total material input to a process step, e.g., methanol decomposition reaction, regardless of whether provided in a single physical stream or multiple physical streams, and whether through a single inlet or multiple inlets. Similarly, a “product stream” is used to mean the total material output from a process step, regardless of whether provided in a single physical stream or multiple physical streams, and whether through a single reactor outlet or multiple reactor outlets.BRIEF DESCRIPTION OF THE FIGURESEmbodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which:FIGURE 1 shows a schematic of a process according to an example embodiment of the invention.FIGURE 2 shows a schematic of an integrated methanol decomposition and Fischer-Tropsch reaction carried out in the same reactor, according to an example embodiment of the invention.FIGURE 3 is a plot showing methanol conversion efficiency at a range of temperatures for methods of the invention (using Ni(5)Mn(5) / ZrC>2 or Ni(5)Mn(5) / AI2O3 as the catalyst) relative to comparative methods with a catalyst having only manganese or a catalyst having only nickel.FIGURE 4 is a plot showing STYW productivity of carbon monoxide at a range of temperatures for methods of the invention (using Ni(5)Mn(5) / ZrO2 or Ni(5)Mn(5) / AI2O3 as the catalyst) relative to comparative methods with a catalyst having only manganese or a catalyst having only nickel.FIGURE 5 is a plot showing STYW productivity for a carbon monoxide, methane, carbon dioxide and dimethyl ether (DME) at 300°C for methods of the invention (using Ni(5)Mn(5) / ZrO2or Ni(5)Mn(5) / AI2O3 as the catalyst) relative to comparative methods with a catalyst having only manganese or a catalyst having only nickel.DETAILED DESCRIPTION OF THE INVENTIONAspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference.Catalyst formatCatalytic materialThe methanol decomposition catalyst comprises manganese and at least one further metal.The further metal may be one or more transition metals selected from Groups 6-12 of the periodic table. In particular embodiments, the methanol decomposition catalyst may comprise one or more of Cr, Fe, Co, Ni, Zn, Ru, Rh, Pd, Ir, or Pt, or mixtures thereof. Optionally, the further metal is selected from a transition metal from groups 7-11 , preferably groups 7, 10 or 11 ; more preferably from groups 10 or 11 , most preferably from group 10. Optionally, the one or more further metals does not include a transition metal from groups 8 or 9.Optionally, the methanol decomposition catalyst comprises a further element, such as one or more of Sc, Y, Ti, Zr, Ce, B, Al, Ga, In, Si, Ge, Sn, or Sb.Optionally, the methanol decomposition catalyst is an alloy, such as an intermetallic alloy.Suitably, the at least one further metal does not include copper.Optionally, only one further metal is present.Preferably, the at least one further metal includes nickel. Optionally, the further metal is nickel alone - for example, the methanol decomposition catalyst consists of manganese and nickel, optionally on a support.Optionally, the methanol decomposition catalyst comprises at least 0.05 wt.% manganese (including any support), such as at least 0.1 wt.% manganese, more preferably at least 0.2 wt.% manganese, at least 0.3 wt.% manganese, at least 0.4 wt.% manganese, at least 0.5 wt.% manganese, at least 1 wt.% manganese, even more preferably at least 1 .5 wt.% manganese, or at least 2 wt.% manganese; and at most 50 wt.% manganese, more preferably at most 20 wt.% manganese and even more preferably at most 10 wt.% manganese.The one or more further metals used alongside manganese may constitute at least 0.1 wt.% based on the total weight of the catalyst (including any support), more preferably at least 0.2 wt.%, at least 0.3 wt.%, at least 0.4 wt.%, at least 0.5 wt.%, at least 1 wt.%, even more preferably at least 1 .5 wt.%, or at least 2 wt.%; and at most 50 wt.%, more preferably at most 20 wt.% and even more preferably at most 10 wt.%.The ratio of manganese to the one or more further metals may be, for example, between 1 :10 to 10:1 ; between 1 :5 to 5:1 , between 1 :2 to 2:1 ; or about 1 :1.SupportThe methanol decomposition catalyst may be a supported catalyst. The support may comprise, e.g. as part of a mixed oxide, or be (e.g. consist of) a refractory oxide, such as oxidized diamond, silica, zirconia, ceria, titania, alumina, lanthanum oxide, or magnesia. Preferably, the support is or comprises, e.g. as part of a mixed oxide, zirconia, titania or alumina. Preferably, the support is or comprises, e.g. as part of a mixed oxide, zirconia or titania, most preferably zirconia.The support material may be in the form of a powder, granulate, shaped particle, such as a preformed sphere or microsphere, or extrudate.In instances where the methanol decomposition catalyst is a supported catalyst, the total amount of metal supported on the support may constitute at least 1 wt.%, at least 2 wt.%, at least 2.5 wt.%, at least 3 wt.%, at least 3.5 wt.%, at least 4 wt.%, at least 4.5 wt.% or at least 5 wt.% of the weight of the methanol decomposition catalyst. The upper limit may be, for example, up to 30 wt.%, up to 20 wt.%, up to 15 wt.% of the weight, or up to 10 wt.% of the methanol decomposition catalyst.For the avoidance of doubt, any metal component of the support is not the “one further metal” of the catalyst.Catalyst formationThe methanol decomposition catalyst may be formed by standard methods known in the art, such as impregnation or co-precipitation.For example, the methanol decomposition catalyst may be formed by impregnating a support material with:(i) a solution containing a manganese compound; and(ii) a solution containing a catalyst-precursor compound comprising the at least one further metal, to form an impregnated support material; and drying and calcining the impregnated support material to form the methanol decomposition catalyst.The manganese compound and catalyst-precursor compound comprising the at least one further metal are generally referred to herein as “catalyst-precursor compounds”.Reference herein to "impregnation" or "impregnating" is intended to refer to contact of the support material with a solution, or solutions, of catalyst-precursor compound(s), before drying in order to achieve precipitation of the catalyst-precursor compound(s). Impregnation with a fully dissolved solution, or solutions, of the catalyst-precursor compound(s) ensures good dispersion of the catalyst-precursor compound(s) on the support material and is thus preferred. This is in contrast, for instance, to the use of partially dissolved catalyst-precursor compound(s) in 'solid solutions' or suspensions, where the level of dispersion of the catalyst-precursor compound(s) across the surface, and in the pores, of the support material can fluctuate depending on the nature of the precipitation on the support material. Furthermore, use of a fully dissolved solution, or solutions, of catalyst-precursor compound(s) also has less of an impact upon the resulting morphology and bulk crush strength of an extrudate formed thereafter compared with solid solutions. Nevertheless, benefits of the present invention can also be realised in the case where a solid solution, or solutions, of a partially undissolved catalystprecursor compound is used.Impregnation of the support material may be achieved by any suitable method of which the skilled person is aware, for instance by vacuum impregnation, incipient wetness, or immersion in excess liquid. The incipient wetness technique is so-called because it requires that the volume of impregnating solution be predetermined so as to provide the minimum volume of solution necessary to just wet the entire surface of the support, with no excess liquid. The excess solution technique as the name implies, requires an excess of the impregnating solution, the solvent being thereafter removed, usually by evaporation. Where a powder or granulate of support material is impregnated, the powder or granulate may be admixed with the impregnating solution by any suitable means of which the skilled person is aware, such as by adding the powder or granulate to a container of the impregnating solution and stirring.The support material may be in the form of a powder, granulate, shaped particle, such as a preformed sphere or microsphere, or extrudate. Reference herein to a powder or granulate of a support material is understood to refer to free flowing particles of a support material or particles of support material that have undergone granulation and / or sieving to be a particular shape (e.g. spherical) and size range. Reference herein to an "extrudate" is intended to mean a support material that has undergone an extrusion step and therefore may be shaped. In the context of the present invention, the powder or granulate is in a form which is suitable for impregnation with a solution of the catalyst-precursor compound(s), and subsequent extrusion or forming into other shaped particles.Suitable catalyst-precursor compounds are those which contain the metal of interest and are thermally decomposable to an oxide of the metal following calcination and which are preferably completely soluble in the impregnating solution. The catalyst-precursor compounds may be, for example, a nitrate, acetate, acetylacetonate, chloride or sulphate of the metal of interest.For example, in the case of manganese the catalyst-precursor compound may be the nitrate, acetate, acetylacetonate, chloride or sulphate of manganese.The solvent of the impregnating solution(s) may be either an aqueous solvent or a nonaqueous, organic solvent. Suitable non-aqueous organic solvents include, for example, alcohols (e.g. methanol, ethanol and / or propanol), ketones (e.g. acetone), liquid paraffinic hydrocarbons, and ethers. Alternatively, aqueous organic solvents, for example an aqueous alcoholic solvent, may be employed. Preferably, the solvent of the impregnating solution(s) is an aqueous solvent.The impregnation of the support material with the catalyst-precursor compound for manganese and the catalyst-precursor compound(s) for the one or more further metals may occur in a single step, without any intermediate drying or calcination steps to separate the loading of the different components. As the skilled person will appreciate, the different catalyst-precursor compounds may be applied to the support material successively or simultaneously in separate impregnation solutions or suspensions, or preferably an impregnation solution or suspension comprising all of the catalyst-precursor compounds is used.The concentration of the one or more catalyst-precursor compounds in the impregnating solution(s) is not particularly limited, although preferably the catalyst-precursor compound(s) is / are fully dissolved. When a powder or granulate of support material is impregnated and immediately followed by an extrusion step, the amount of the impregnating solution(s) is preferably suitable for forming an extrudable paste.Impregnation of the support material is usually followed by drying of the impregnating solution in order to effect precipitation of the catalyst-precursor compound(s) on to the support material and preferably also to remove bound solvent of the impregnating solution (e.g. water). Drying therefore does not, for instance, lead to full decomposition of the catalyst-precursorcompound(s) or otherwise lead to a change in oxidation state of such compounds. As will be appreciated, in embodiments where an extrusion is performed, complete drying and removal of solvent (e.g. bound solvent) of the impregnating solution may occur after forming of a shaped particle, for example by extrusion. Drying is suitably conducted at temperatures from 50 °C to 150 °C, preferably 75 °C to 125 °C. Suitable drying times are, for example, from 5 minutes to 72 hours. Drying may suitably be conducted in a drying oven or in a box furnace, for example, under the flow of an inert gas at elevated temperature.Next, the impregnated support material is subjected to a calcination step. As will be understood, calcination is required for converting the catalyst-precursor compound which has been impregnated on the support material into an oxide. Thus, calcination leads to thermal decomposition of the catalyst-precursor compound(s), and not merely removal of bound solvent of an impregnating solution, as for instance in the case of drying. Calcination may be performed by any method known to those of skill in the art, for instance in a fluidized bed, rotary kiln, box furnace or ashing furnace at a temperature of at least 250 °C, preferably from 275 °C to 500 °C.Finally, the methanol decomposition catalyst may be activated prior to / during use, for example, by reduction (reductive activation). A person of skill in the art can identify suitable conditions for activating the catalyst. The methanol decomposition catalyst may be activated using hydrogen gas as reducing agent. The hydrogen gas may be mixed with other gases, such as an inert carrier gas. Examples of such inert carrier gases include nitrogen, carbon dioxide, argon, or helium.Processing conditionsThe contacting of the feed stream comprising methanol with the metal decomposition catalyst occurs at a temperature and pressure suitable to effect efficient methanol decomposition.The temperature may be, for example, 200-500°C, such as 200-450°C, or 200-400°C, or 200- 350°C, or 200-300°C, or 250-500°C, or 250-450°C, or 250-400°C, or 250-300°C, or 300-500°C, or 300-450°C, or 300-400°C.The pressure may be, for example, in the range of 0 to 50 barg (barg referring to pressure in bars above ambient or atmospheric pressure), such as between 10-40 barg.The gas hourly space velocity (GHSV) for continuous operation may be in the range 50 to 200,000 r1, such as 10,000 to 200,000 IT1, 50,000 to 200,000 IT1, or 100,000 to 200,000 IT1.Feed streamThe methanol is provided as part of a feed stream. In instances where the products of methanol decomposition are themselves used as the feed stream for a further process, the feed stream provided to the methanol decomposition catalyst may be referred to as the “first feed stream”.Preferably the feed stream comprises at least 5 mol% methanol (the mol% being calculated as a percentage of the whole feed stream). For example, in particular embodiments, the feed stream comprises at least 7.5 mol% methanol, e.g., at least 10 mol% methanol, or at least 15 mol% methanol, or at least 20 mol% methanol, or at least 25 mol% methanol.Optionally, the feed stream may also comprise one or more additional gases, which may be inert or reactive. In such embodiments, the feed stream may further comprise one or more of H2, CO, CO2, and N2(including gases recycled from the product stream of the reaction, as discussed in more detail below).Preferably, the feed stream may comprise an inert carrier gas, wherein the inert carrier gas includes one or more of CO2and N2, preferably N2. Such a gas may serve as a diluent.Additionally, or alternatively, H2and / or CO may be added to the feed stream to tune the decomposition reaction and / or provide a desired product. In such embodiments, the feed stream further comprises H2and / or CO. In various embodiments as otherwise described herein, one or more of H2, CO, CO2, and N2may be present in first feed stream an amount in the range of up to 90 mol%, e.g., up to 80 mol%, up to 80 mol%, up to 60 mol%, up to 50 mol%, or up to 40 mol%, or up to 30 mol% (the mol% being calculated as a percentage of the whole feed stream).The components of the feed stream may be delivered as one or more combined feed stream(s), separate feed streams, or any combination thereof. By the term "combined feed stream" it is meant a feed stream which contains at least part of two or more of the components. By the term "separate feed stream" it is meant a feed stream which contains only one of the components.Optionally, the feed stream may incorporate water. The water may be present in the methanol delivered to the feed stream; for example, the water content of the liquid methanol may be adjusted by addition of water or by dehydration. The molar ratio of water to methanol (water:methanol) in the feed stream may be, for example, up to 30:70, up to 20:80, or up to 10:80. For example, the lower limit for the molar ratio of water to methanol may be, for example, 0.05:99.95, 0.1 :99.9, 1 :99, 2:98, 3:97, 4:96; or 5:95. Suitable ranges for the molar ratio may be, for example, 1 :99 to 30:70; 1 :99 to 20:80; 1 :99 to 10:80; or 2:98 to 10:80.Preferably, hydrogen is delivered as part of the feed stream. The hydrogen used in the process may be derived from any suitable source. Non-limiting examples of processes which may provide a source of hydrogen that may be used in the process of the present invention include synthesis gas generation processes; the hydrolysis of water; and various other chemical processes, such as, for example, ethane crackers, styrene manufacture and catalytic reforming.Carbon monoxide used in the process may likewise be derived from any suitable source. Nonlimiting examples of processes which may provide a source of carbon monoxide that may be used in the process of the present invention include synthesis gas generation processes; thereduction of metal oxides; and various other chemical processes, such as, for example, the high temperature reaction of air or oxygen with a carbonaceous material (for example coal).The feed stream may be provided at elevated temperature. For example, the feed stream may have a temperature in the range of 200-500°C, e.g., 200-450°C, or 200-400°C, or 200-350°C, or 200-300°C, or 250-500°C, or 250-450°C, or 250-400°C, or 250-300°C, or 300-500°C, or 300- 450°C, or 300-400°C.Productivity and selectivityPreferably, the decomposition of methanol is performed with a conversion efficiency of methanol of at least 30%, e.g., at least 40%, or at least 50%, or at least 60%, or at least 65%, or at least 70%, or at least 75%. By “conversion efficiency” we mean the weight percentage of methanol in the product stream as a percentage of the weight of methanol in the feed stream.Due to the consumption of methanol in the reaction, the product stream preferably includes no more than 75 mol% methanol, e.g., no more than 60 mol% methanol, no more than 50 mol% methanol, or no more than 25 mol% methanol (the mol% being calculated as a percentage of the whole product stream).Preferably, the product stream comprises at least 20 mol% total of CO and H2, e.g., at least 35 mol%, or at least 50 mol%, or at least 65 mol%. Without wishing to be bound by theory, methanol decomposition under these conditions is expected to generate two moles of H2per mole of CO. Accordingly, in various embodiments as otherwise described herein, the first product stream has a molar ratio of hydrogen to carbon monoxide in the range of 0.5:1 to 5:1 , e.g., 1 :1 to 3:1 , or 1 .5:1 to 2.5:1 , or 1 .5:1 to 3.5:1 .Preferably, the product stream comprises no more than 50 mol% of methane e.g. no more than 40 mol% methane, no more than 30 mol% methane, no more than 20 mol% methane, no more than 15 mol% methane, no more than 10 mol% methane, no more than 5 mol% methane, no more than 3 mol% methane, no more than 2 mol% methane, or no more than 1 mol% methane.Preferably, the product stream comprises no more than 20 mol% of CO2, e.g. no more than 15 mol% CO2, no more than 10 mol% CO2, no more than 5 mol% CO2, no more than 3 mol% CO2, no more than 2 mol% CO2, or no more than 1 mol% CO2.Preferably, the product stream comprises no more than 20 mol% of DME, e.g. no more than 15 mol% DME, no more than 10 mol% DME, no more than 5 mol% DME, no more than 3 mol% DME, no more than 2 mol% DME, or no more than 1 mol% DME.Preferably, the product stream comprises no more than 20 mol% of methyl formate, e.g. no more than 15 mol% methyl formate, no more than 10 mol% methyl formate, no more than 5 mol% methyl formate, no more than 3 mol% methyl formate, no more than 2 mol% methyl formate, or no more than 1 mol% methyl formate.Preferably, the decomposition of methanol is performed with high selectivity for CO over other carbon products (i.e. with minimal formation of side-products including methane, CO2, DME and methyl formate) - that is with high carbon product selectivity for CO. When referring to “carbon product selectivity” of the decomposition process for a particular component, we mean the space time yield (STY) of the component as a percentage of the STY for all carbon-containing products from the methanol decomposition, subtracting the contribution from any components not derived from methanol decomposition (for example, if carbon monoxide is added to the feed stream then the contribution from this is subtracted from the carbon monoxide in the product stream). In this disclosure, STY is reported as the grams of product produced per kilogram of catalyst per hour (space time yield weight, or STYW), although those skilled in the art will recognise that the carbon product selectivity is a percentage which is independent of the particular units used for the STY.Preferably, the decomposition of methanol is performed with a carbon product selectivity of at least 50% for CO, e.g., at least 60%, or at least 70%, or at least 80%, or at least 90% for CO.Preferably, the decomposition of methanol is performed with a carbon product selectivity of no more than 50% for methane e.g., no more than 40%, no more than 30%, no more than 20%, no more than 15%, or no more than 10%, or no more than 5%.Preferably, the decomposition of methanol is performed with a carbon product selectivity of no more than 20% for CO2, e.g., no more than 15%, or no more than 10%, or no more than 5%.Preferably, the decomposition of methanol is performed with a carbon product selectivity of no more than 20% for dimethyl ether (DME), e.g., no more than 15%, or no more than 10%, or no more than 5%.Preferably, the decomposition of methanol is performed with a carbon product selectivity of no more than 20% for methyl formate, e.g., no more than 15%, or no more than 10%, or no more than 5%.Particularly preferred are methods which are performed with a carbon product selectivity of greater than 60% for CO and less than 40% for methane, more preferably less than 70% for CO and less than 30% for methane.Reactor typeThe reaction zone of the present invention can conveniently be any reactor, multiple reactors, such as a series of reactors, or a part thereof, wherein the process of the present invention occurs.Suitable reactors which may be used in the process of the present invention include adiabatic bed, multi-tubular, fluidised bed, spinning basket and buss loop, and heat exchanger reactors. When more than one reactor is used, the reactors may be arranged either in series or inparallel. For reactors utilised in series, heat exchangers and / or intercoolers and / or additional reactant and / or recycle of intermediates can be employed in between successive reactors to control the reaction temperature. In one embodiment of the present invention, the process is performed in at least two adiabatic reactors in series.An example embodiment is shown in schematic view in FIG. 1 . Here, in process 100 a crude methanol stream 102 is optionally combined with a feed of one or more further gases 104 to form a first feed stream 106 which is delivered into reactor 1 10. Reactor 110 includes a methanol decomposition reaction zone in which with methanol decomposition catalyst 112 is contacted with the first feed stream 106 and product stream 120 is formed. Here, product stream 120 is conducted from the methanol decomposition reaction zone, and unreacted methanol is substantially separated from the product stream 120 (e.g., at least 50%, at least 75%, at least 90% or at least 95% unreacted methanol is separated) and is recycled to the first feed stream 106 via methanol recycle 108.Processing of the product streamPreferably the method involves separating components from the product stream. In particular, the method preferably comprises separating CO and H2from the product stream, optionally separating CO and H2independently.Preferably, at least a portion of the product stream is recycled to the feed stream. For example, preferably at least a portion of methanol is separated from the first product stream and recycled to the feed stream.Optionally, at least a portion of the CO2is separated from the product stream. The CO2may be recycled to the feed stream or may be subjected to further processing. For example, the CO2may be separated and used as the feed stream for a reverse water-gas shift (reverse WGSR) to form carbon monoxide and water.Optionally, at least a portion of the methane is separated from the product stream. The methane may be recycled to the feed stream or may be subjected to further processing. For example, the methane may be separated and used as the feed stream for a methane reforming process (such as steam reforming or autothermal reforming) to generate further hydrogen.Optionally, the CO and H2are stored for further use. Alternatively, the CO and H2may be used as a feedstock for further processing, such as the Fischer-Tropsch reaction to produce hydrocarbons (as described in the applicant’s earlier application WO 2024 / 033867).Fischer-TropschThe present invention also provides a process for performing an integrated Fisher-Tropsch synthesis, the process comprising: providing a first feed stream comprising methanol;contacting the first feed stream with a methanol decomposition catalyst comprising manganese to decompose at least a portion of the methanol to form a first product stream comprising H2and CO in a method according to the first aspect of the invention; optionally providing a second feed stream comprising H2and at least a portion of the CO of the first product stream; and contacting the first product stream or, optionally, the second feed stream, with a Fischer- Tropsch catalyst to perform a Fischer-Tropsch synthesis to provide a second product stream comprising Cs+ hydrocarbons.The Fischer-Tropsch step of the method may be carried out in the manner taught in the applicant’s earlier application WO 2024 / 033867.The temperature of the Fischer-Tropsch synthesis can suitably be in the range of 200-400 °C, such as 200-300 °C, or 210-400 °C, or 210-300 °C, or 220-400 °C, or 220-300 °C. For example, the temperature of the Fischer-Tropsch synthesis may be in the range of 200-250 °C, such as 200-240 °C, or 200-230 °C, or 200-220 °C, or 210-250 °C, or 210-240 °C, or 210-230 °C, or 220-250 °C, or 220-240 °C, or 230-250 °C. The pressure of the reaction may suitably be in the range from 10-50 barg, such as 20-50 barg, or 25-50 barg, or 10-40 barg, or 20-40 barg, or 25-40 barg or 10-35 barg, or 20-35 barg, or 25-35 barg. For example, the contacting of the first product stream or second feed stream with the Fischer-Tropsch catalyst may be performed at a pressure in the range of 20-40 barg.The Fischer-Tropsch catalyst may be selected by the person of ordinary skill in the art. In various embodiments as otherwise described herein, the Fischer-Tropsch catalyst comprises cobalt, iron, rhodium, ruthenium, or a combination thereof (e.g., comprises cobalt or iron). In particular embodiments, the Fischer-Tropsch catalyst comprises cobalt in an amount in the range of 2 to 30 wt.%, e.g., in the range of 5 to 25 wt.%, or in the range of 8 to 20 wt.%, calculated as Co(0), as a weight percentage of the Fischer-Tropsch catalyst. In particular embodiments, the Fischer-Tropsch catalyst comprises iron in an amount in the range of 15 to 95 wt.%, e.g., 25 to 95 wt.%, or 30 to 90 wt.%, calculated as Fe(0). In various embodiments as otherwise described herein, the Fischer-Tropsch catalyst further comprises manganese (e.g., comprises manganese in the amount of 0.1 to 15 wt.%, or 1 to 10 wt.%).In various embodiments as otherwise described herein, the Fischer-Tropsch catalyst is a supported catalyst, wherein the support comprises at least one of titanium oxide, zirconium oxide, cerium oxide, aluminum oxide, silicon oxide, magnesium oxide, and zinc oxide (e.g., comprises at least one of titanium oxide, aluminum oxide, and silicon oxide). For example, in particular embodiments, the support is a titanium dioxide support, or is an alumina support, or is a silica support. In various embodiments, the support is a shaped particle, e.g., an extrudate. The catalyst can be prepared using methods conventional in the art.Suitably, the Fischer-Tropsch catalyst may be activated prior to use. The Fischer-Tropsch catalyst may be activated by reductive activation, in the manner described above in relation to the methanol decomposition catalyst.Suitably, the methanol decomposition catalyst is different to the Fischer-Tropsch catalyst.The contacting of the second feed stream with the Fischer-Tropsch catalyst and the contacting of the first feed stream with the methanol decomposition catalyst may be performed in the same plant. This can be, e.g., within different beds in the same reactor, or in different reactors. In such embodiments, the two processes may be integrated together to provide efficient transformation of methanol to hydrocarbons.Suitably, the first reaction zone comprises a first reactor in which the methanol decomposition catalyst is disposed, and wherein the second reaction zone comprises a second reactor in which the Fischer-Tropsch catalyst is disposed. The first reaction zone comprises a first catalyst bed in which the methanol decomposition catalyst is disposed, and the second reaction zone comprises a second catalyst bed in which the Fischer-Tropsch catalyst is disposed. Optionally, the first catalyst bed and the second catalyst bed are disposed within the same reactor, e.g., in catalyst stacks or catalyst bed sections. In such situations, the reactor may be held at a temperature and pressure to achieve efficient decomposition of methanol and efficient Fischer-Tropsch synthesis. As demonstrated in the examples below, this may be, for example, a temperature in the range of 200-400°C, in particular at around 300-350°C.An example of such an arrangement is shown in Figure 2. Here, first feed stream 221 is provided to stacked bed reactor 225, which includes a methanol decomposition reaction zone 220 (here, a first bed of the stacked-bed reactor that includes the methanol decomposition catalyst 223) and a Fischer-Tropsch reaction zone 230 (here, a second bed of the stacked-bed reactor that includes the Fischer-Tropsch catalyst 233). The first feed stream 221 is contacted with the methanol decomposition catalyst 223 to provide a first product stream 222 that includes CO and H2. The first product stream is provided to the Fischer-Tropsch reaction zone as second feed stream 231 , which is contacted with Fischer-Tropsch catalyst 233 to provide a second product stream 232 that includes Cs+hydrocarbons. Here, at least a portion of the Cs+ hydrocarbons of the second product stream is conducted to hydroprocessing unit 260, where it is hydroprocessed to provide an end-product stream 265. Here, at least a portion of H2of the first product stream is separated and conducted to the hydrotreating unit 260 via stream 262. H2can also be provided to the hydrotreating unit in the portion of the second product stream that is conducted to the hydrotreating unit.Particularly preferred embodimentsIn especially preferred embodiments, the method of decomposition methanol utilizes a methanol decomposition catalyst comprising nickel and manganese, preferably as the sole metals.Preferably the nickel and manganese are provided on the same support, preferably on zirconia or alumina, most preferably on zirconia. The amount of nickel may be between 1 -10 wt.%, for example, 4-10 wt.%, in particular 5-10 wt.%. The amount of manganese may be between 1 -10 wt.%, for example, 4-10 wt.%, in particular 5-10 wt.%. Preferably, the reaction is carried out at a temperature of less than 500°C, preferably at 200-400°C, more preferably at between 300- 350°C (in particular when the support is zirconia).EXPERIMENTAL EXAMPLESCatalysts were prepared and tested according to the method of the invention.Example 1 - Ni(5)Mn(5) / ZrO2catalystA catalyst having 5 wt.% Ni and 5 wt.% Mn on a zirconia support was produced by co-impregnation. 1.363 g of nickel (II) nitrate hexahydrate and 1.437 g of manganese (II) nitrate (anhydrous) were dissolved in 5 g of deionized water in a round bottom flask, to which 5 g of zirconium dioxide (ZrO2) were added rapidly under vigorous stirring. To this 15 mL of de-ionized water was added, and the mixture stirred at 400 rpm at room temperature. After 4 hours the temperature was increased to 80°C to evaporate water. Once the water had evaporated, the sample was dried further in an oven at 60°C for 18 hours. After drying, the catalyst was ground using a pestle and mortar, and sieved to select particles having a size of 500 pm or less using a Fisherbrand™ Stainless Steel Test Sieve. The catalyst was then calcined by ramping the temperature from ambient temperature to 120°C at 10°C / min, holding at 120°C for 2 hours, ramping the temperature to 500°C at 2°C / min, holding at 500°C for a further 4 hours, and then allowing to cool to ambient temperature. Subsequent to calcining, the catalyst was sieved using a Fisherbrand™ Stainless Steel Test Sieve to select particles between 100-200 pm.The catalyst was loaded into a 16-channel parallel fixed-bed stainless steel reactor system. Each stainless steel reactor (300 mm in length; 3 mm external diameter; 2 mm internal diameter) housed a 25 mg bed of catalyst (having particle size fraction of 100 to 200 microns diameter) loaded on top of a 6 cm deep bed of an inert material (carborundum). The reactor volume above the catalyst was also packed with carborundum. The reactor was set-up in a down-flow configuration. Each reactor was maintained at a temperature of 60-400 °C and at a total pressure of 10 barg throughout the reactions, according to the scheme set out in Table 1 below. Different feeds were employed to determine the impact on the yield of carbon monoxide and hydrogen whilst maintaining a GHSV of 165,000 IT1. The effluent stream from each reactor was diluted with inert gas (nitrogen) and was periodically analysed by online gas chromatography to determine the yield of carbon monoxide and hydrogen product.The reactor conditions used are set out in steps 1 -13 below, with steps 1-8 serving as an activation step. Monitoring of the reaction products was carried out in steps 10-13 to determine the effect of increasing temperature on catalyst performance.Table 1Example 2 - NKSIMnfSVAbQs catalystA catalyst containing 5 wt.% Ni and 5 wt.% Mn on an alumina support was produced by co- impregnation, using the same procedure as Example 1 , but using 5 g of AI2O3 instead of ZrO2.The catalyst was activated and tested using the same procedure taught in Example 1 .Comparative Example 1 - Ni(5) / ZrO2catalystA manganese-free catalyst containing 5 wt.% Ni on a zirconia support was produced by impregnation, using the same procedure as Example 1 , but using 1 .239 g of nickel (II) nitrate hexahydrate and without any manganese containing compounds. The catalyst was activated and tested using the same procedure taught in Example 1 .Comparative Example 2 - Mn(5) / ZrO2catalystA nickel-free catalyst containing 5 wt.% manganese on a zirconia support was produced by impregnation, using the same procedure as Example 1 , but using 1 .437 g of Mn(NOa)2 withoutany nickel containing compounds. The catalyst was activated and tested using the same procedure taught in Example 1 .Comparative Example 3 - T-2130As a comparative example, a commercially-available copper zinc oxide catalyst (T-2130, available from Sud Chemie) was used, having the composition: 33 wt.% CuO and 66 wt.% ZnO. This catalyst was chosen as a comparative catalyst since it is the most preferred methanol decomposition catalyst type highlighted in the applicant’s earlier application WO 2024 / 033867. It is also known for use in methanol synthesis from syngas, and hence is expected to be a suitable methanol decomposition catalyst based on the principle of microscopic reversibility.The catalyst was activated and tested using the same procedure taught in Example 1 .ResultsThe results of the experiments are summarised in Table 2.These data show that the Ni(5)Mn(5) catalysts achieve high methanol conversion efficiencies and carbon monoxide productivity, displaying particularly good performance at the lower temperatures tested.For example, at 300°C both Ni(5)Mn(5) / ZrO2 and Ni(5)Mn(5) / AI2O3 had CO productivities which were around double that produced by Ni(5) / ZrO2at a comparable level (in the case of Ni(5)Mn(5) / ZrO2) or lower level (in the case of Ni(5)Mn(5) / AI2O3) of methane productivity, and with a greater level of methanol conversion. The Mn(5) / ZrO2did not display any methanol conversion at this temperature, indicating that the much higher conversion for the NiMn catalysts was not due to an additive effect of the metals, but due specifically to the effect of the two metals together. At this temperature the Cu / ZnO catalyst had a very low methanol conversion, with no reported carbon monoxide conversion.At 350°C Ni(5)Mn(5) / ZrO2showed similar behaviour, but displayed an even greater methanol conversion efficiency - again outperforming the comparative Ni(5) / ZrO2catalyst and T-2130. The Mn(5) / ZrO2again did not display any appreciable methanol conversion at this temperature.At 400°C the methanol conversion efficiency and CO productivity of Ni(5)Mn(5) / ZrO2remained higher than for Ni(5) / ZrO2, with both catalysts displaying an increase in selectivity for CO over other products compared to lower temperatures. Whilst the methanol conversion for T-2130 increased at 400°C, the productivity of carbon monoxide dropped significantly, and was nearly 5 times less than for Ni(5)Mn(5) / ZrO2. The Mn(5) / ZrO2again did not show any appreciable methanol conversion.Turning to the Ni(5)Mn(5) / AI2O3 catalyst, the data show that after displaying comparable results to Ni(5)Mn(5) / ZrO2at 300°C in step 10, the results diverge at 350°C in step 1 1 and 400°C in step 12. Specifically, Ni(5)Mn(5) / AI2C>3 displayed a near complete conversion of methanol, butalmost exclusively to methane. The methane productivity dropped over time in both steps 1 1 and 12, and when the temperature was reduced back to 350°C in step 13 the catalyst then showed the highest methanol conversion and carbon monoxide productivity of the tested catalyst during this step. Without wishing to be bound by theory, the data suggest that during earlier steps 11 -12 the Ni(5)Mn(5) / Al20s catalyst was changing / activating / stabilising, and that by step 13 the catalyst was better suited to carbon monoxide production.To further illustrate the effect of the introduction of manganese, Figures 3-5 show the effect of the addition of 5 wt.% manganese to a catalyst containing 5 wt.% nickel on zirconia. At all tested temperatures the methanol conversion was higher (Figure 3), and the CO productivity showed similar behaviour (Figure 4). Figure 5 shows productivity data at 300°C, and shows that the increase in performance comes without significant increase in production of sideproducts - in particular, the production of methane, carbon dioxide and DME remains comparable before and after addition of manganese.Table 2***The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example + / - 10%.REFERENCESA number of publications are cited above in order to more fully describe and disclose the invention and the state of the art to which the invention pertains. Full citations for these references are provided below. The entirety of each of these references is incorporated herein. 1) WO 2024 / 0338672) US 4,716,8593) US 6,541 ,1424) US 9,833,7735) Usami, et al., “Catalytic methanol decomposition at low temperatures over palladium supported on metal oxides.” Appl. Cat. A 171 (1 ): 123-130 (1998)6) Hargreaves, J.S.J. and Ormsby, G. Catalysis 2007, 20. 107-121.7) Cheng, W.H. etal. Appl. Catal. A.: Gen., 1995, 130, 138) Cheng, W.H. etal. Appl. Catal. A.: Gen., 1998, 170, 2159) Xi, J. and Lu, G. Appl. Catal. A.: Gen., 2002, 225, 77 10) Cheng, W.H. Appl. Catal. B.: Environ., 1995, 7, 12711 ) JP 2003-093879 A12) A. Mosayebi “Kinetic modelling and experimental investigations of dry reforming of methanol over a Cr-Mo-Mn / SiO2 catalyst” Research on Chemical Intermediates (2021 ) 47:2951 -2972

Claims

CLAIMS1 . A method of decomposing methanol, the method comprising: contacting methanol with a methanol decomposition catalyst to decompose at least a portion of the methanol to form H2and CO, the methanol decomposition catalyst comprising manganese and at least one further metal, wherein the methanol decomposition catalyst does not comprise copper.

2. A method according to claim 1 , wherein the at least one further metal comprises nickel, palladium or platinum.

3. A method of decomposing methanol, the method comprising: contacting methanol with a methanol decomposition catalyst to decompose at least a portion of the methanol to form H2and CO, the methanol decomposition catalyst comprising manganese and at least one further metal, the at least one further metal comprising nickel.

4. A method according to any one of the preceding claims, wherein the methanol decomposition catalyst comprises manganese and nickel.

5. A method according to any one of the preceding claims, wherein the methanol decomposition catalyst does not comprise a Group 8 metal or a Group 9 metal.

6. A method according to any one of the preceding claims, wherein the manganese is present in an amount of at least 0.05% by weight of the methanol decomposition catalyst, based on the total weight of the methanol decomposition catalyst.

7. A method according to any one of the preceding claims, wherein the manganese is present in an amount at most 10% by weight of the methanol decomposition catalyst, based on the total weight of the methanol decomposition catalyst.

8. A method according to any one of the preceding claims, wherein the at least one further metal is present in an amount up to 10% by weight of the methanol decomposition catalyst, based on the total weight of the methanol decomposition catalyst.

9. A method according to any one of the preceding claims, wherein the total amount of the manganese and the at least one further metal is up to 20% by weight of the methanol decomposition catalyst, based on the total weight of the methanol decomposition catalyst.

10. A method according to any one of the preceding claims, wherein the manganese and the at least one further metal are supported on a support.11 . A method according to claim 10, wherein the support is selected from zirconia, alumina, titania, ceria, and silica, or a mixed oxide comprising a mixture of two or more of zirconia, alumina, titania, ceria, and silica.

12. A method according to claim 11 , wherein the support is selected from zirconia, alumina, and titania, or a mixed oxide comprising a mixture of two or more of zirconia, alumina, and titania.

13. A method according to claim 10, wherein the support is selected from zirconia and alumina or a mixed oxide comprising a mixture of zirconia and alumina, or wherein the support comprises zirconia.

14. Use of a methanol decomposition catalyst to improve methanol decomposition in a method of decomposing methanol, the methanol decomposition catalyst comprising manganese and at least one further metal, wherein:(i) the methanol decomposition catalyst does not comprise copper; and / or(ii) the at least one further metal comprises nickel, optionally wherein the improvement in methanol decomposition is an increase in methanol conversion and / or an increase in CO selectivity.

15. A process for performing an integrated Fisher-Tropsch synthesis, the process comprising: providing a first feed stream comprising methanol contacting the first feed stream with a methanol decomposition catalyst comprising manganese to decompose at least a portion of the methanol to form a first product stream comprising H2and CO in a method according to any one of claims 1 to 11 ; optionally providing a second feed stream comprising H2and at least a portion of the CO of the first product stream; and contacting the first product stream or, optionally, the second feed stream, with a Fischer- Tropsch catalyst to perform a Fischer-Tropsch synthesis to provide a second product stream comprising Cs+ hydrocarbons.

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