A Ni2P / attapulgite clay catalyst, its preparation method and application

Abstract

The application belongs to the technical field of catalyst preparation, and particularly discloses a Ni2P / attapulgite clay catalyst, a preparation method and application thereof; the carrier of the catalyst is attapulgite clay, the active component is Ni2P, and the loading amount of the active component Ni2P is 20% to 80% of the total mass of the catalyst. In the application, attapulgite clay is used as the carrier to load Ni2P, and the Ni2P / attapulgite clay catalyst is prepared by the impregnation method, so that the Ni2P is uniformly distributed in the structure of the attapulgite clay. When the obtained Ni2P / attapulgite clay catalyst is used for catalyzing the selective methanation of CO, the catalyst has high selectivity and hydrothermal stability.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, and relates to a Ni2P / attapulgite clay catalyst, its preparation method, and its application in the selective methanation reaction of CO. Background Technology

[0002] Proton exchange membrane fuel cells (PEMFCs) can use H2 produced through online reforming of hydrocarbons as fuel, offering high energy density and efficiency, making them suitable for electric vehicles and home power generation. However, the Pt anode material in PEMFCs is highly sensitive to CO. Even after preliminary purification, the hydrogen-rich gas produced through reforming still contains less than 2% CO by volume, which readily adsorbs onto the electrode surface, poisoning the Pt electrode, hindering the adsorption and oxidation of H2, and severely impacting battery performance. Therefore, the small amount of CO in the hydrogen-rich reformed gas still needs further purification and removal, with its concentration needing to be controlled below 10 ppm (International Journal of Hydrogen Energy, 2023, Vol. 48, pp. 24996-25005). Selective CO methanation can deeply remove CO from hydrogen-rich reformed gas. It is simple to operate and the temperature is easy to control. The products H2O and CH4 are harmless to Pt electrodes. Supported metal Ni catalysts have been widely studied and applied due to their good catalytic activity (International Journal of Hydrogen Energy, 2021, Vol. 46, pp. 31467-31488).

[0003] However, hydrogen-rich reformed gases often contain about 15% CO2. Therefore, during the purification of CO from hydrogen-rich reformed gases using CO methanation, CO2 and H2 methanation may also occur. CO2 participation in the reaction consumes a large amount of H2, which is detrimental to the efficiency of H2 as fuel. Therefore, CO2 methanation should be suppressed as much as possible during the purification process (International Journal of Hydrogen Energy, 2019, Vol. 44, pp. 9978-9986). Studies have found that the adsorption and activation of CO and H2 occur on the surface of active metals, while CO2 is mainly adsorbed on the surface of oxide supports, forming activated intermediate adsorbed species, which then overflow H from the Ni metal surface or react directly with Ni metal. It is evident that the adsorption and activation of CO2 are significantly different from those of CO. CO2 participation in the reaction can be prevented by inhibiting the overflow of activated H or CO2 adsorption (International Journal of Hydrogen Energy, 2023, Vol. 48, pp. 24996-25005). To suppress the CO2 methanation reaction, the loading of metallic Ni is typically kept low, usually around 10%. Conversely, a low loading leads to low CO methanation activity. Furthermore, hydrogen-rich reforming gas contains a small amount of H2O. Even after drying, a large amount of H2O is generated during the CO methanation process, causing the catalyst to be in a hydrothermal environment for an extended period. This can lead to hydration of the catalyst support, causing pore structure collapse and resulting in the migration and aggregation of active metallic Ni, leading to deactivation (Journal of Colloid and Interface Science, 2015, Vol. 447, pp. 68-76). To improve the hydrothermal stability of metallic Ni catalysts, traditional methods involve adding small amounts of additives, such as SiO2, which can effectively improve hydrothermal stability. However, under longer reaction times and higher temperatures, the catalyst still deactivates rapidly (Journal of Colloid and Interface Science, 2015, Vol. 447, pp. 68-76). Meanwhile, the addition of SiO2 to the support can also inhibit CO2 adsorption and improve the selectivity of CO methanation reaction (ChemCatChem, 2022, Vol. 14, e202101281).

[0004] Therefore, it is evident that introducing appropriate additives into the catalyst support can effectively improve the hydrothermal stability of the catalyst, while simultaneously regulating its surface properties, inhibiting CO2 adsorption, and enhancing the selectivity of supported Ni metal catalysts for CO methanation. However, this does not improve the internal structure of the catalyst, and when applied to the deep purification of hydrogen-rich gas through selective CO methanation, it is difficult to simultaneously achieve both reaction selectivity and activity, and the lifespan remains relatively short. Summary of the Invention

[0005] The present invention aims to provide a Ni2P / attapulgite clay catalyst, which uses attapulgite clay as a support to support a greater amount of metallic Ni and phosphates the metallic Ni, thereby improving the hydrothermal stability of the catalyst, suppressing the overflow of activated H, preventing the activation of adsorbed CO2, and improving the activity and selectivity of the catalyst for the CO methanation reaction in hydrogen-rich gas. Another objective of the present invention is to provide a method for preparing the catalyst, which prepares the Ni2P / attapulgite clay catalyst by precipitation, so that nickel phosphide is uniformly distributed in the attapulgite clay structure. A further objective of the present invention is to provide the application of this catalyst in the field of deep purification of hydrogen-rich gas using the selective methanation reaction of CO.

[0006] This invention is achieved through the following technical solution: A Ni2P / attapulgite clay catalyst, wherein the catalyst support is attapulgite clay, the active component is phosphated metallic Ni, i.e., Ni2P, and the loading of the active component Ni2P is 20%~80%.

[0007] A further improvement to the present invention is as follows: A method for preparing a Ni2P / attapulgite clay catalyst includes the following steps: attapulgite clay is calcined in a muffle furnace, cooled, and ground into powder. A certain amount of attapulgite clay is weighed and dispersed in distilled water. Ni(NO3)2·6H2O is then weighed and dissolved in distilled water to obtain an aqueous solution of Ni(NO3)2. Anhydrous Na2CO3 is separately weighed and dissolved in an equal volume of distilled water to obtain an aqueous solution of Na2CO3. The prepared Ni(NO3)2 and Na2CO3 aqueous solutions are simultaneously added dropwise to the aqueous solution containing attapulgite clay to form a new precipitate. After aging, the precipitate is repeatedly washed with distilled water until neutral. Finally, it is dried, pressed into tablets, sieved, and reduced to obtain the Ni / attapulgite clay catalyst. The obtained Ni / attapulgite clay catalyst is then loaded into a fixed-bed reactor, a PH3 / H2 mixed gas is introduced, the temperature is raised to the phosphating temperature, and maintained for a certain time to obtain the Ni2P / attapulgite clay catalyst.

[0008] Furthermore, the attapulgite clay is calcined at a temperature of 240℃~360℃ for 1~4 hours.

[0009] Furthermore, the aging temperature for forming new precipitates is 60℃~90℃, and the time is 0.5~2 h.

[0010] Furthermore, the mass of Ni(NO3)2·6H2O is calculated based on the mass of Ni it contains; the loading of Ni is 20%~80%.

[0011] Furthermore, the temperature for drying the filtered sample is 80~120℃. Furthermore, the dried powder sample is passed through a 40-60 mesh sieve.

[0012] Furthermore, the reduction temperature is 400~500℃, the reducing gas is H2, and the reduction time is 1~4 h.

[0013] Furthermore, the volume fraction of PH3 in the PH3 / H2 mixed gas is 1% to 20%.

[0014] Furthermore, the phosphating temperature is 150~350℃.

[0015] Furthermore, the phosphating time is 1 to 12 hours.

[0016] A further improvement of the present invention is as follows: The application of a Ni2P / attapulgite clay catalyst in the deep purification of small amounts of CO in hydrogen-rich gas is specifically achieved by catalyzing the selective methanation reaction of CO in hydrogen-rich gas.

[0017] In this invention, the loading amount is the percentage of the mass of Ni2P to the total mass of the prepared Ni2P / attapulgite clay catalyst.

[0018] The beneficial effects of this invention are as follows: This invention uses attapulgite clay as a carrier. Attapulgite clay is a porous, layered, hydrous magnesium-aluminate silicate clay mineral with characteristics of high porosity and large specific surface area. Furthermore, it contains a large amount of water and exhibits high hydrothermal stability compared to oxides such as Al₂O₃. It also boasts low application cost and high mechanical strength, making it suitable as a carrier for metallic Ni. Phosphating the supported metallic Ni effectively suppresses the overflow of activated H₂ on the Ni surface, thereby preventing the reaction of CO₂ adsorbed on the adjacent carrier and improving the selectivity of the CO methanation reaction. Since CO₂ activation is inhibited, the loading of metallic Ni can be significantly increased, thereby enhancing CO adsorption and conversion, and improving the reactivity of CO methanation. Therefore, the prepared Ni₂P / attapulgite clay catalyst, used for the selective methanation of CO in hydrogen-rich gas, improves both the activity and selectivity of the catalyst for CO methanation while also enhancing its hydrothermal stability.

[0019] In the preparation method of this invention, attapulgite clay is used as a support, and a Ni / attapulgite clay catalyst is prepared by precipitation, so that Ni is uniformly distributed in the attapulgite clay structure, thereby improving the hydrothermal stability of the catalyst. Then, it is reduced and phosphated in a hydrogen atmosphere to improve the activity and selectivity of the CO selective methanation reaction. Simultaneously, the loading of metallic Ni in the catalyst is further optimized to give the catalyst even better catalytic activity.

[0020] The Ni2P / attapulgite clay catalyst of this invention is used for the selective methanation of CO. Data shows that, when the metallic Ni loading reaches 60%, after phosphating, the space velocity of a hydrogen-rich mixed gas (CO / CO2 / H2 / N2 = 1 / 20 / 69 / 10) passing through a fixed-bed reactor at atmospheric pressure is 6000 mL h⁻¹. −1 g −1 Under these conditions, the Ni2P / attapulgite clay catalyst, after hydrothermal treatment at 150℃, still exhibits very high activity. It can purify CO to below 10 ppm at 220℃, and even when the reaction temperature is increased to 320℃, the CO concentration in the gas after the reaction remains below 10 ppm. It can also effectively inhibit CO2 methanation, and the selectivity of the CO methanation reaction can be maintained above 50%. It has a large operable temperature range and shows good prospects for industrialization. Attached Figure Description

[0021] Figure 1 This is a schematic diagram showing the concentration of CO in hydrogen-rich gas after purification by the catalyst before and after hydrothermal treatment in this invention. Figure 2 This is a schematic diagram showing the selectivity results of the catalyst before and after hydrothermal treatment for the selective methanation of CO in this invention. Detailed Implementation

[0022] Reference ratio 1 14.71 g of Al(NO3)3·9H2O and 14.86 g of Ni(NO3)2·6H2O were weighed and dissolved in water to prepare 100 mL solutions. Separately, 13.98 g of Na2CO3 was dissolved in water to prepare another 100 mL solution. Both solutions were simultaneously added dropwise to 200 mL of distilled water at 80 °C with stirring, resulting in a blue-green precipitate. After aging for 1 hour, the precipitate was washed with distilled water until neutral and dried in an oven at 120 °C. The resulting sample was then pressed into tablets, crushed, and sieved through a 40-60 mesh sieve. Finally, it was reduced in a hydrogen atmosphere at 450 °C for 2 h to obtain a Ni / Al2O3 catalyst with a Ni metal loading of 60%, sample numbered Ni / Al2O3.

[0023] Reference ratio 2 14.71 g of Al(NO3)3·9H2O and 14.86 g of Ni(NO3)2·6H2O were weighed and dissolved in water to prepare 100 mL solutions. Separately, 13.98 g of Na2CO3 was dissolved in water to prepare 100 mL solutions. Both solutions were simultaneously added dropwise to 200 mL of distilled water at 80℃ with stirring, resulting in a blue-green precipitate. After aging for 1 hour, the precipitate was washed with distilled water until neutral and dried in an oven at 120℃. The resulting sample was then pressed into tablets, crushed, and sieved through a 40-60 mesh sieve. It was then reduced in a hydrogen atmosphere at 450℃ for 2 h. After the temperature dropped to 300℃, a 5% (v / v) PH3 / H2 mixed gas was introduced and maintained for 2 h, yielding a Ni2P / Al2O3 catalyst with a 60% Ni metallic loading. The sample was designated Ni2P / Al2O3. Example 1

[0024] The purchased attapulgite clay raw material was calcined in a muffle furnace at 300°C for 2 hours. After cooling to room temperature, it was ground into powder and labeled ATP.

[0025] Reference ratio 3 2.0 g of ATP solid powder from Example 1 was weighed and dispersed in 200 mL of aqueous solution, and heated to 80 °C. Separately, 14.86 g of Ni(NO3)2·6H2O was weighed and dissolved in water to prepare 100 mL of aqueous solution; and 6.50 g of Na2CO3 was dissolved in water to prepare 100 mL of solution. Under stirring, the above Ni(NO3)2 and Na2CO3 solutions were simultaneously added dropwise to the above 200 mL aqueous solution containing ATP dispersed at 80 °C, forming a blue-green precipitate. After aging for 1 hour, the precipitate was washed with distilled water until neutral and dried in an oven at 120 °C. The resulting sample was then pressed into tablets, crushed and passed through a 40-60 mesh sieve, and then reduced in a hydrogen atmosphere at 450 °C for 2 h to obtain a Ni / ATP catalyst with a Ni metal loading of 60%, sample numbered Ni / ATP. Example 2

[0026] 2.0 g of ATP solid powder from Example 1 was weighed and dispersed in 200 mL of aqueous solution, and heated to 80 °C. Separately, 14.86 g of Ni(NO3)2·6H2O was weighed and dissolved in water to prepare 100 mL of aqueous solution; 6.50 g of Na2CO3 was also dissolved in water to prepare 100 mL of solution. The Ni(NO3)2 and Na2CO3 solutions were simultaneously added dropwise to the 200 mL aqueous solution containing ATP dispersed at 80 °C under stirring, resulting in a blue-green precipitate. After aging for 1 hour, the precipitate was washed with distilled water until neutral and dried in an oven at 120 °C. The resulting sample was then pressed into tablets, crushed, and sieved through a 40-60 mesh sieve. It was then reduced in a hydrogen atmosphere at 450 °C for 2 hours. After the temperature dropped to 300 °C, a 5% (v / v) PH3 / H2 mixed gas was introduced and maintained for 2 hours, yielding a Ni2P / ATP catalyst with a 60% Ni metal loading. The sample was designated Ni2P / ATP.

[0027] Reference ratio 4 The Ni / Al2O3 catalyst prepared in reference ratio 1 was weighed and transferred to a hydrothermal reactor containing 20 mL of water in an N2 atmosphere. The temperature was increased to 150℃ at 1℃ / min and maintained for 8 h. After cooling to room temperature, the catalyst was filtered and dried. The resulting sample was numbered Ni / Al2O3-H.

[0028] Reference ratio 5 The Ni2P / Al2O3 catalyst prepared in reference ratio 2 was weighed and transferred to a hydrothermal reactor containing 20 mL of water in an N2 atmosphere. The temperature was increased to 150℃ at 1℃ / min and maintained for 8 h. After cooling to room temperature, the catalyst was filtered and dried. The resulting sample was numbered Ni2P / Al2O3-H.

[0029] Reference ratio 6 The Ni / ATP catalyst prepared in reference ratio 3 was weighed and transferred to a hydrothermal reactor containing 20 mL of water in an N2 atmosphere. The temperature was increased to 150℃ at 1℃ / min and maintained for 8 h. After cooling to room temperature, the catalyst was filtered and dried. The resulting sample was numbered Ni / ATP-H. Example 3

[0030] The Ni2P / ATP catalyst prepared in Example 2 was weighed and transferred to a hydrothermal reactor containing 20 mL of water in an N2 atmosphere. The temperature was increased to 150°C at 1°C / min and maintained for 8 h. After cooling to room temperature, the catalyst was filtered and dried. The resulting sample was numbered Ni2P / ATP-H.

[0031] Reference ratio 7 0.4 g of Ni / Al₂O₃ sample from reference ratio 1 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 220 °C, a hydrogen-rich gas was introduced, wherein V(H₂) / V(CO) / V(CO₂) / V(N₂) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0032] Reference ratio 8 0.4 g of the Ni2P / Al2O3 sample from reference ratio 2 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 220 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0033] Reference ratio 9 0.4 g of the Ni / ATP sample from reference ratio 3 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 220 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 . Example 4

[0034] 0.4 g of the Ni2P / ATP sample from Example 2 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, once the catalyst bed temperature dropped to 220 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0035] Reference ratio 10 0.4 g of Ni / Al₂O₃ sample from reference ratio 1 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 320 °C, a hydrogen-rich gas was introduced, wherein V(H₂) / V(CO) / V(CO₂) / V(N₂) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0036] Reference ratio 11 0.4 g of the Ni2P / Al2O3 sample from reference ratio 2 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 320 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0037] Reference ratio 12 0.4 g of the Ni / ATP sample from reference ratio 3 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 320 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 . Example 5

[0038] 0.4 g of the Ni2P / ATP sample from Example 2 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, once the catalyst bed temperature dropped to 320 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0039] Reference ratio 13 0.4 g of the Ni / Al₂O₃-H sample from reference ratio 4 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 220 °C, a hydrogen-rich gas was introduced, wherein V(H₂) / V(CO) / V(CO₂) / V(N₂) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0040] Reference ratio 14 0.4 g of the Ni2P / Al2O3-H sample from reference ratio 5 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 220 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0041] Reference ratio 15 0.4 g of the Ni / ATP-H sample from reference ratio 6 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 220 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 . Example 6

[0042] 0.4 g of the Ni2P / ATP-H sample from Example 3 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, once the catalyst bed temperature dropped to 220 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0043] Reference ratio 16 0.4 g of the Ni / Al₂O₃-H sample from reference ratio 4 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 320 °C, a hydrogen-rich gas was introduced, wherein V(H₂) / V(CO) / V(CO₂) / V(N₂) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0044] Reference ratio 17 0.4 g of the Ni2P / Al2O3-H sample from reference ratio 5 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 320 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0045] Reference ratio 18 0.4 g of the Ni / ATP-H sample from reference ratio 6 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, when the catalyst bed temperature dropped to 320 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 . Example 7

[0046] 0.4 g of the Ni2P / ATP-H sample from Example 3 was weighed and loaded into a micro fixed-bed reactor with an outer diameter of 8 mm. The temperature was increased to 450 °C at a rate of 1 °C / min, and then reduced in a flowing hydrogen atmosphere for 2 h. After reduction, once the catalyst bed temperature dropped to 320 °C, a hydrogen-rich gas was introduced, wherein V(H2) / V(CO) / V(CO2) / V(N2) = 69 / 1 / 20 / 10, and GHSV = 6000 mL / h. −1 g −1 The concentration of CO in the reactor outlet gas after the reaction at atmospheric pressure is shown in the figure. Figure 1 The selectivity analysis results of the CO methanation reaction are shown in [the table below]. Figure 2 .

[0047] Depend on Figure 1 , Figure 2 It can be seen that when the Ni loading reaches 60%, after phosphating, the space velocity of a hydrogen-rich mixed gas (CO / CO2 / H2 / N2=1 / 20 / 69 / 10) passing through a fixed-bed reactor at atmospheric pressure is 6000 mL h⁻¹. −1 g −1 Under these conditions, the Ni2P / attapulgite clay catalyst, after hydrothermal treatment at 150℃, still exhibits very high activity. It can purify CO to below 10 ppm at 220℃, and even when the reaction temperature is increased to 320℃, the CO concentration in the gas after the reaction remains below 10 ppm. It can also effectively inhibit CO2 methanation, and the selectivity of the CO methanation reaction can be maintained above 50%. It has a large operable temperature range and shows good prospects for industrialization.

[0048] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A Ni2P / attapulgite clay catalyst, characterized in that, The catalyst is supported on attapulgite clay, the active component is Ni2P, and the loading of metallic Ni is 60%. The catalyst is prepared in the following steps: S1. Place the attapulgite clay in a muffle furnace and calcine it. Cool it and grind it into powder. Weigh a certain amount of the powdered attapulgite clay and disperse it in distilled water. S2. Weigh out Ni(NO3)2·6H2O and dissolve it in distilled water to obtain an aqueous solution of Ni(NO3)2; separately weigh out anhydrous Na2CO3 and dissolve it in the same volume of distilled water to obtain an aqueous solution of Na2CO3. Add the two aqueous solutions prepared above dropwise to the aqueous solution in S1 to form a new precipitate. After the precipitate ages, wash it repeatedly with distilled water until it is neutral. Finally, dry, press, sieve and reduce to obtain Ni / attapulgite clay catalyst. S3. Weigh the catalyst from S2 and load it into a fixed-bed reactor. Introduce a PH3 / H2 mixed gas, heat it to the phosphating temperature, and maintain it for a certain time to obtain the Ni2P / attapulgite clay catalyst.

2. The Ni2P / attapulgite clay catalyst according to claim 1, characterized in that: The attapulgite clay described in S1 is calcined at a temperature of 240~360℃ for 2~4 hours.

3. The Ni2P / attapulgite clay catalyst according to claim 1, characterized in that: The aging temperature for the formation of new precipitates described in S2 is 80~120℃, and the time is 0.5~2 h.

4. The Ni2P / attapulgite clay catalyst according to claim 1, characterized in that: The sieving mentioned in S2 refers to passing through a 40-60 mesh sieve.

5. The Ni2P / attapulgite clay catalyst according to claim 1, characterized in that: The drying temperature described in S2 is 70~90℃.

6. The Ni2P / attapulgite clay catalyst according to claim 1, characterized in that: During the reduction process described in S2, the temperature is 400~500℃, the reducing gas is H2, and the time is 1~4 h.

7. The Ni2P / attapulgite clay catalyst according to claim 1, characterized in that: In S3, the volume fraction of PH3 in the PH3 / H2 mixed gas is 1%~20%.

8. The Ni2P / attapulgite clay catalyst according to claim 1, characterized in that: The phosphating temperature described in S3 is 150~350℃, and the phosphating time is 1~12 h.

9. The application of the Ni2P / attapulgite clay catalyst as described in claim 1 in the deep purification of small amounts of CO in hydrogen-rich gas.

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