Ni / D-TiOSO4 nanocatalysts, their preparation methods, and applications

Abstract

This application belongs to the field of catalyst preparation technology, specifically relating to a Ni / D-TiOSO4 nanocatalyst, its preparation method, and its application. The catalyst comprises D-TiOSO4 nanosheets and Ni nanoparticles dispersed on the D-TiOSO4 nanosheets; the D-TiOSO4 nanosheets are oxygen-deficient TiOSO4 nanosheets; the average particle size of the Ni nanoparticles is 2.9 nm–3.6 nm, and the Ni content is 3.4 wt%–15.0 wt%. The Ni / D-TiOSO4 nanocatalyst provided by this invention exhibits excellent catalytic performance, 100% H2 selectivity, and outstanding stability. Furthermore, after adding 0.1 M NaOH at 298 K, the TOF significantly increases to 414.1 min. ‑1 It has good application prospects.

Description

Technical Field

[0001] This application belongs to the field of catalyst preparation technology, specifically relating to a Ni / D-TiOSO4 nanocatalyst, its preparation method, and its application. Background Technology

[0002] Hydrogen (H2), as a green and sustainable energy carrier, has attracted much attention due to its high energy density and environmental friendliness. However, the safe and efficient storage of hydrogen remains a key challenge. Chemical hydrogen storage is now considered an efficient and convenient method. Ammonia borane (NH3BH3, AB) has attracted considerable attention due to its excellent hydrogen storage properties (theoretical hydrogen storage density of 19.6 wt%, excellent chemical stability, and environmental friendliness), and is considered one of the most promising chemical hydrogen storage carriers for industrialization. Under the action of a highly efficient catalytic system, ammonia borane can be hydrolyzed (NH3BH3 + 2H2O → NH4+). 4+ + BO 2- (+ 3H2) enables controlled hydrogen release under mild conditions.

[0003] Nickel-based transition metal catalysts, with their significant cost advantages and considerable catalytic activity, have become a research hotspot in the field of non-precious metal catalysis for the hydrolysis of ammonia borane to produce hydrogen. However, nickel nanoparticles (Ni NPs) are prone to particle aggregation, leading to a decrease in their activity during the catalytic process, which severely restricts their practical application. Therefore, there is an urgent need to develop non-precious metal catalysts with high stability and high catalytic activity for the rapid catalytic hydrolysis of ammonia borane to produce hydrogen. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a Ni / D-TiOSO4 nanocatalyst, its preparation method, and its application. Specifically, the following technical solution is adopted:

[0005] In a first aspect, the present invention provides a Ni / D-TiOSO4 nanocatalyst, the Ni / D-TiOSO4 nanocatalyst comprising D-TiOSO4 nanosheets and Ni nanoparticles dispersed on the D-TiOSO4 nanosheets; wherein the D-TiOSO4 nanosheets are oxygen-deficient TiOSO4 nanosheets.

[0006] The average particle size of the Ni nanoparticles is 2.9 nm-3.6 nm, and the Ni content is 3.4 wt%-15.0 wt%.

[0007] The Ni / D-TiOSO4 nanocatalyst provided by this invention exhibits excellent activity due to the strong metal-support interaction, ultrafine Ni metal nanoparticles, and the introduction of oxygen vacancies to increase the electron density on the surface of the Ni nanoparticles. The use of a TiOSO4 matrix with abundant oxygen vacancy defects as a support not only provides more active sites for water molecule dissociation but also induces electron-rich states in the metal active sites through electron transfer effects, enhancing the metal particles' ability to activate water molecules and promoting their dissociation, thereby improving catalytic activity. Furthermore, this catalyst features small particle size, numerous catalytic active sites, high catalytic activity and stability, making it a promising catalyst for future development.

[0008] Secondly, the present invention provides a method for preparing the above-mentioned Ni / D-TiOSO4 nanocatalyst, comprising the following steps:

[0009] TiOSO4 powder was dispersed in water, then a nickel source precursor was added, and the mixture was ultrasonically treated to obtain a suspension.

[0010] A reducing agent is added to the suspension to carry out a reduction reaction until no more bubbles are generated, thereby obtaining the Ni / D-TiOSO4 nanocatalyst.

[0011] In this preparation method, a reducing agent is used to reduce the nickel source precursor to generate Ni nanoparticles, which are then dispersed on TiOSO4 nanosheets. The operation is simple and the cost is low.

[0012] As a further preferred embodiment, the nickel source precursor is NiCl2·6H2O.

[0013] As a further preferred embodiment, the mass ratio of the TiOSO4 powder to the NiCl2·6H2O is 10mg-50mg:1.77mg-8.85mg.

[0014] As a further preferred embodiment, the reducing agent is NaBH4.

[0015] As a further preferred embodiment, the ratio of NaBH4 to TiOSO4 powder is 10 mg-40 mg: 10 mg-50 mg.

[0016] In the above preparation process, the amount of sodium borohydride used affects the catalytic performance of the final Ni / D-TiOSO4 nanocatalyst. By controlling the amount of sodium borohydride used in the synthesis of Ni / D-TiOSO4 nanocatalyst, the oxygen defect concentration of the catalyst can be adjusted, thereby changing the catalytic performance of the Ni / D-TiOSO4 nanocatalyst. EPR and XPS characterization analyses show that during the impregnation and reduction preparation process of Ni / D-TiOSO4 nanocatalyst, titanium in the TiOSO4 nanosheets is in the +4 valence state, and under the action of reducing agents such as NaBH4, it is partially reduced to Ti. 3+ , and Ti 3+ It is also easily oxidized to Ti 4+ In Ti 3+ With Ti 4+ During the interconversion process, a large number of oxygen vacancy defects are generated. The TiOSO4 matrix, rich in oxygen vacancy defects, not only provides more active sites for the dissociation of water molecules, but also induces the metal active sites to adopt an electron-rich state through electron transfer effects, thereby enhancing the ability of metal particles to activate water molecules and promoting their dissociation, thus improving catalytic activity. Furthermore, the TiOSO4 matrix can also promote the uniform dispersion and size control of metal nanoparticles, which will further enhance catalytic activity. When the amount of sodium borohydride is 30 mg, the Ni / D-TiOSO4 nanocatalyst exhibits the best performance for the hydrolysis of ammonia borane to produce hydrogen.

[0017] As a further preferred embodiment, the TiOSO4 powder is prepared by the following steps:

[0018] Titanium sulfate was calcined to obtain a pale yellow TiOSO4 powder.

[0019] As a further preferred embodiment, the titanium sulfate is placed in a muffle furnace and heated at a rate of 5 °C / min. -1 Heat to 500 ℃ and calcine for 4 h.

[0020] This invention synthesizes TiOSO4 nanosheets using anhydrous titanium sulfate via a simple calcination method. The titanium element in the TiOSO4 nanosheets is in the +4 valence state, and can be partially reduced to Ti in the presence of reducing agents such as NaBH4. 3+ , and Ti 3+ It is also easily oxidized to Ti 4+ In Ti 3+ With Ti 4+During the interconversion process, oxygen vacancy defects are easily generated. The oxygen-vacancy-rich TiOSO4 matrix not only provides more active sites for the dissociation of water molecules, but also induces the metal active sites to adopt an electron-rich state through electron transfer effects, enhancing the ability of metal particles to activate water molecules and promoting their dissociation, thereby improving catalytic activity. Furthermore, this TiOSO4 matrix can also promote the uniform dispersion and size control of metal nanoparticles, which will further enhance catalytic activity.

[0021] Thirdly, the present invention provides the application of the above-mentioned Ni / D-TiOSO4 nanocatalyst in the catalytic hydrolysis of ammonia borane to produce hydrogen.

[0022] As a further preferred embodiment, the Ni / D-TiOSO4 nanocatalyst uses NaOH as an additive when catalyzing the hydrolysis of ammonia borane to produce hydrogen, wherein the concentration of NaOH is 0.25M-2.0M.

[0023] The Ni / D-TiOSO4 nanocatalyst exhibited excellent catalytic activity and 100% H2 selectivity in the hydrolysis of ammonia borane to produce hydrogen. Under conditions without NaOH additives, the time-of-conversion (TOF) of the catalytic reaction reached 145.1 min at 298 K. -1 As the NaOH concentration increased, the catalytic reaction rate showed a trend of first increasing and then decreasing. At 1.0 M, the prepared Ni / D-TiOSO4 nanocatalyst catalyzed the hydrolysis of ammonia borane to produce hydrogen in only 0.24 min, with its TOF value increasing to a high level of 414.1 min. -1 This represents a 5.0-fold increase in commercial Pt / C.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) The Ni / D-TiOSO4 nanocatalyst provided by the present invention exhibits excellent catalytic performance, 100% H2 selectivity, and outstanding stability. Under additive-free conditions, the Ni / D-TiOSO4 nanocatalyst achieves a conversion frequency (TOF) of 145.1 min at 298 K for the hydrolysis of ammonia borane to produce hydrogen. -1 When 0.1 M NaOH was added, the TOF significantly increased to 414.1 min. -1 ;

[0026] (2) The Ni / D-TiOSO4 nanocatalyst provided by the present invention has the advantages of high efficiency, stability and low preparation cost. This catalyst can accelerate the practical application of the ammonia borane hydrogen storage system. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 The image shows the electron paramagnetic resonance (EPR) spectra of the Ni / D-TiOSO4 nanocatalysts prepared in Examples 1-4 of this invention.

[0029] Figure 2 The figure shows the Ti 2p X-ray photoelectron spectroscopy (XPS) spectra of the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 of the present invention and the TiOSO4 support prepared in Comparative Example 2.

[0030] Figure 3 The image shows the O 1s X-ray photoelectron spectroscopy (XPS) spectra of the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 of this invention and the TiOSO4 support prepared in Comparative Example 2.

[0031] Figure 4 The figure shows the XPS analysis results of the Ni / D-TiOSO4 nanocatalysts prepared in Examples 1-4 of this invention;

[0032] Figure 5 The images shown are transmission electron microscope (TEM) images of the TiOSO4 support prepared in Example 1 of the present invention (shown in (a)), transmission electron microscope (TEM) images of the Ni / D-TiOSO4 nanocatalyst (shown in (b) and (c)), and particle size distribution of Ni nanoparticles (shown in (d)).

[0033] Figure 6 The image shown is a transmission electron microscope (TEM) image of the Ni nanocatalyst prepared in Comparative Example 1 of the present invention (shown in (a)) and a particle size distribution of Ni nanoparticles (shown in (b)).

[0034] Figure 7 The figures shown are the performance test graphs (shown in (a)) and the corresponding TOF value graphs (shown in (b)) of the Ni / D-TiOSO4 nanocatalysts prepared in Examples 1-4 of this invention catalyzing the hydrolysis of ammonia borane to produce hydrogen under different NaBH4 dosages.

[0035] Figure 8 The figures shown are the performance test graphs (shown in (a)) and the corresponding TOF value graphs (shown in (b)) of the Ni / D-TiOSO4 nanocatalysts prepared in Examples 1, 5-8 of this invention under different amounts of TiOSO4.

[0036] Figure 9 The figures shown are the performance graphs (a) and (b) of the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 of the present invention and the Ni nanocatalyst, TiOSO4 support, Ni (PVP) + D-TiOSO4 nanocatalyst and Ni (PVP) + TiOSO4 nanocatalyst prepared in Comparative Examples 1-4, respectively, for the catalytic hydrolysis of ammonia borane to produce hydrogen.

[0037] Figure 10 The figures shown are the performance graphs (a) and the corresponding TOF values ​​(b) of the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 of this invention for catalyzing the hydrolysis of ammonia borane to produce hydrogen under different NaOH concentrations.

[0038] Figure 11 The figures shown are: Cyclic stability test diagram of the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 of the present invention catalyzing the hydrolysis of ammonia borane to produce hydrogen (shown in (a)); and Cyclic performance diagram of Ni / D-TiOSO4-x (x = 10 mg-40 mg) prepared with different amounts of NaBH4 catalyzing the hydrolysis of ammonia borane to produce hydrogen (shown in (b)). Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] Example 1

[0041] A method for preparing Ni / D-TiOSO4 nanocatalysts, specifically comprising the following steps:

[0042] (1) Preparation of TiOSO4

[0043] 5 g of Ti(SO4)2 was calcined in a muffle furnace at 500 °C for 4 h (heating rate of 5 °C·min). -1 ), yielding 40 mg of TiOSO4 pale yellow powder;

[0044] (2) Preparation of Ni / D-TiOSO4 nanocatalysts

[0045] The 40 mg TiOSO4 pale yellow powder obtained in step 1 was ultrasonically dispersed in 5 mL of deionized water, and then 7.13 mg NiCl2·6H2O was added. The dispersion was continued by ultrasonication to ensure that the components were mixed evenly. Subsequently, 30 mg NaBH4 was added to the suspension for reduction. After no gas was produced, Ni nanoparticles with a Ni content of 4.2 wt% and supported by D-TiOSO4 were obtained, namely Ni / D-TiOSO4-30 nanocatalyst (where 30 refers to the amount of sodium borohydride added).

[0046] Example 2

[0047] A method for preparing Ni / D-TiOSO4 nanocatalyst is similar to that in Example 1, except that the amount of NaBH4 in step (2) of Example 1 is changed from 30 mg to 10 mg. The other steps are exactly the same, and Ni / D-TiOSO4-10 nanocatalyst is obtained (where 10 refers to the amount of sodium borohydride added).

[0048] Example 3

[0049] A method for preparing Ni / D-TiOSO4 nanocatalyst is similar to that in Example 1, except that the amount of NaBH4 in step (2) of Example 1 is changed from 30 mg to 20 mg. The other steps are exactly the same, and Ni / D-TiOSO4-20 nanocatalyst is obtained (where 20 refers to the amount of sodium borohydride added).

[0050] Example 4

[0051] A method for preparing Ni / D-TiOSO4 nanocatalyst is similar to that in Example 1, except that the amount of NaBH4 in step (2) of Example 1 is changed from 30 mg to 40 mg. The other steps are exactly the same, and Ni / D-TiOSO4-40 nanocatalyst is obtained (where 40 refers to the amount of sodium borohydride added).

[0052] Example 5

[0053] A method for preparing Ni / D-TiOSO4 nanocatalyst is similar to that in Example 1, except that the amount of TiOSO4 light yellow powder in step (2) of Example 1 is changed from 40 mg to 50 mg. The other steps are exactly the same, and Ni / D-TiOSO4 nanocatalyst with Ni content of 3.4 wt% is obtained.

[0054] Example 6

[0055] A method for preparing Ni / D-TiOSO4 nanocatalyst is similar to that in Example 1, except that the amount of TiOSO4 light yellow powder in step (2) of Example 1 is changed from 40 mg to 30 mg. The other steps are exactly the same, and Ni / D-TiOSO4 nanocatalyst with Ni content of 5.5 wt% is obtained.

[0056] Example 7

[0057] A method for preparing Ni / D-TiOSO4 nanocatalyst is similar to that in Example 1, except that the amount of TiOSO4 light yellow powder in step (2) of Example 1 is changed from 40 mg to 20 mg. The other steps are exactly the same, and Ni / D-TiOSO4 nanocatalyst with Ni content of 8.1 wt% is obtained.

[0058] Example 8

[0059] A method for preparing Ni / D-TiOSO4 nanocatalyst is similar to that in Example 1, except that the amount of TiOSO4 light yellow powder in step (2) of Example 1 is changed from 40 mg to 10 mg. The other steps are exactly the same, and Ni / D-TiOSO4 nanocatalyst with Ni content of 15 wt% is obtained.

[0060] Comparative Example 1

[0061] A method for preparing Ni nanocatalysts is similar to step (2) in Example 1, except that TiOSO4 pale yellow powder is not added in step (2) of Example 1. The other steps are exactly the same as step (2) in Example 1, and Ni nanocatalysts are obtained.

[0062] Comparative Example 2

[0063] A method for preparing a TiOSO4 vector is identical to step (1) in Example 1, yielding 40 mg of TiOSO4 vector.

[0064] Comparative Example 3

[0065] A method for preparing Ni(PVP)+TiOSO4 nanocatalysts, specifically including the following steps:

[0066] (1) Preparation of TiOSO4 vector

[0067] 5 g of anhydrous Ti(SO4)2 was calcined in a muffle furnace at 500 °C for 4 h (heating rate of 5 °C·min). -1 The resulting TiOSO4 carrier was pale yellow.

[0068] (2) Preparation of Ni(PVP) nanoparticles

[0069] 7.13 mg NiCl2·6H2O and 10 mg polyvinylpyrrolidone (PVP) were dissolved in 5 mL of deionized water and ultrasonically dispersed. Then, 30 mg NaBH4 was added to carry out the reduction reaction. After no gas was produced, the mixture was centrifuged and washed to obtain Ni(PVP)NPs.

[0070] (3) Preparation of Ni(PVP)+TiOSO4 nanocatalyst

[0071] Weigh 40 mg of the TiOSO4 support obtained in step (1), disperse it in 5 mL of deionized water and sonicate it. Then add the Ni(PVP) NPs obtained in step (2) and continue to sonicate it to make it uniformly dispersed, so as to obtain the Ni(PVP)+TiOSO4 catalyst.

[0072] Comparative Example 4

[0073] A method for preparing Ni(PVP)+D-TiOSO4 nanocatalyst, specifically including the following steps:

[0074] (1) Preparation of TiOSO4 vector

[0075] 5 g of anhydrous Ti(SO4)2 was calcined in a muffle furnace at 500 °C for 4 h (heating rate of 5 °C·min). -1 ), yielding 40 mg of pale yellow TiOSO4 vector.

[0076] (2) Preparation of D-TiOSO4 vector

[0077] 40 mg of pale yellow TiOSO4 powder was ultrasonically dispersed in 5 mL of deionized water. Subsequently, 30 mg of NaBH4 was added to the suspension for reduction to obtain the D-TiOSO4 carrier.

[0078] (3) Preparation of Ni(PVP) nanoparticles

[0079] 7.13 mg NiCl2·6H2O and 10 mg polyvinylpyrrolidone (PVP) were dissolved in 5 mL of deionized water and ultrasonically dispersed. Then, 30 mg NaBH4 was added to carry out the reduction reaction. After no gas was produced, the mixture was centrifuged and washed to obtain Ni(PVP)NPs.

[0080] (4) Preparation of Ni(PVP)+D-TiOSO4 nanocatalysts

[0081] The Ni(PVP) NPs obtained in step (3) are added to the D-TiOSO4 suspension obtained in step (2) and ultrasonically dispersed to obtain Ni(PVP)+D-TiOSO4 catalyst.

[0082] Characterization data for some of the materials obtained in the above embodiments are as follows:

[0083] Figure 1 The figures shown are the electron paramagnetic resonance (EPR) spectra of the Ni / D-TiOSO4 nanocatalysts prepared in Examples 1-4 of this invention; and by Figure 1 It can be seen that the Ni / D-TiOSO4-x (where x refers to the amount of sodium borohydride added, x = 10 mg-40 mg) prepared in Examples 1-4 all exhibit a symmetrical EPR signal peak at g = 2.003, which corresponds to oxygen vacancy defects in the material. It is worth noting that the intensity of the characteristic peak is positively correlated with the amount of NaBH4 added, indicating that the concentration of the reducing agent can control the defect concentration in the crystal.

[0084] Figure 2 The image shows the Ti 2p X-ray photoelectron spectroscopy (XPS) spectra of the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 and the TiOSO4 support prepared in Comparative Example 2. Figure 2 It can be seen that the Ti 2p spectrum in Ni / D-TiOSO4 can be deconvolved into four sets of characteristic peaks, among which 458.8 and 464.8 eV correspond to Ti 4+ 2p 3 / 2 and 2p 1 / 2 The peaks, while 457.8 and 463.7 eV indicate that Ti 3+ The existence of species corresponds to Ti. 3+ 2p 3 / 2 and 2p 1 / 2 Peak. Compared with Example 1, Ti was not detected in the TiOSO4 carrier sample prepared in Comparative Example 2. 3+ The signal indicates that the reduction treatment successfully induced partial reduction of titanium sites. The charge imbalance generated by this mixed valence structure provides a driving force for the formation of oxygen vacancies on the catalyst surface.

[0085] Figure 3 The image shows the O 1s X-ray photoelectron spectroscopy (XPS) spectra of the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 of this invention and the TiOSO4 support prepared in Comparative Example 2; and by Figure 3It can be seen that the O 1s spectrum exhibits a double peak characteristic at 531.0 eV (Ti-O bond) and 532.7 eV (surface hydroxyl / adsorbed water). Compared with Comparative Example 2, the Ti-O peak position in the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 is positively shifted, indicating that chemical reduction leads to the formation of oxygen-rich defects. This structural characteristic may enhance catalytic efficiency by optimizing the electronic environment of active sites, which is consistent with the results of electron paramagnetic resonance (EPR) spectroscopy and Ti 2p X-ray photoelectron spectroscopy (XPS) analysis.

[0086] Figure 4 The image shows the XPS analysis results of the Ni / D-TiOSO4 nanocatalysts prepared in Examples 1-4 of this invention; and by Figure 4 It can be seen that Ni 0 2p 3 / 2 The binding energy showed a trend of first decreasing and then increasing with the increase of reducing agent dosage (853.9 eV to 852.8 eV), indicating that the electron density of metallic Ni first increased and then decreased, which corresponds to their catalytic activity.

[0087] Figure 5 The figures shown are transmission electron microscopy (TEM) images of the TiOSO4 support prepared in Example 1 of this invention (shown in (a)), TEM images of the Ni / D-TiOSO4 nanocatalyst (shown in (b) and (c)), and a particle size distribution of Ni nanoparticles (shown in (d)); and by Figure 5 It can be seen that Ni NPs with an average particle size of 2.9 nm are uniformly dispersed on TiOSO4 nanosheets.

[0088] Figure 6 The image shown is a transmission electron microscope (TEM) image (a) of the Ni nanocatalyst prepared in Comparative Example 1 of this invention and a particle size distribution chart of the Ni nanoparticles (b). Figure 6 It can be seen that the average particle size of unsupported Ni NPs is significantly increased to 19.8 nm. Therefore, a suitable support can disperse metal nanoparticles, making them less prone to aggregation, thereby maintaining their high catalytic activity.

[0089] Example 9

[0090] The specific process of using the Ni / D-TiOSO4 nanocatalyst prepared in Examples 1-4 of this invention to catalyze the hydrolysis of ammonia borane to produce hydrogen is as follows:

[0091] The catalyst was placed in a 50 mL flask containing 4.7 mL of deionized water. The amount of catalyst was the same as that prepared in each example. 1 mmol of ammonia borane was added at 298 K atmospheric pressure to initiate the reaction. The hydrogen production performance graph and corresponding TOF values ​​are shown below. Figure 7As shown in Table 1, the conditions for catalyst preparation and the results of catalytic reactions in Examples 1-4 are as follows.

[0092] Table 1. Catalytic performance of Ni / D-TiOSO4 nanocatalysts prepared in Examples 1-4 for hydrogen production via hydrolysis of ammonia borane.

[0093]

[0094] Table 1 shows that the catalytic reaction rate of the Ni / D-TiOSO4 nanocatalysts prepared in Examples 1-4 for the hydrolysis of ammonia borane to produce hydrogen exhibits a trend of first increasing and then decreasing with the increase of NaBH4 dosage. At a dosage of 30 mg, the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 shows the best performance for the hydrolysis of ammonia borane to produce hydrogen. This indicates that the oxygen defect concentration of the catalyst can be adjusted by regulating the amount of sodium borohydride used in the synthesis of Ni / D-TiOSO4 nanocatalysts. The TiOSO4 matrix with oxygen-rich vacancies not only provides more active sites for the dissociation of water molecules but also induces the metal active sites to be in an electron-rich state through electron transfer effects, improving the ability of metal particles to activate water molecules and promoting the dissociation of water molecules, thereby enhancing the catalytic activity and resulting in different catalytic performances of the finally prepared Ni / D-TiOSO4 nanocatalysts in the reaction.

[0095] Example 10

[0096] The specific process of catalyzing the hydrolysis of ammonia borane to produce hydrogen using the Ni / D-TiOSO4 nanocatalyst prepared in Examples 1 and 5-8 of this invention is as follows:

[0097] The catalyst was placed in a 50 mL flask containing 4.7 mL of deionized water. The amount of catalyst was the same as that prepared in each example. 1 mmol of ammonia borane was added at 298 K atmospheric pressure to initiate the reaction. The hydrogen production performance graph and corresponding TOF values ​​are shown below. Figure 8 As shown in Table 2, the conditions for catalyst preparation and the results of catalytic reactions in Examples 1, 5-8 are as follows.

[0098] Table 2. Catalytic performance of Ni / D-TiOSO4 nanocatalysts prepared in Examples 1, 5-8 for hydrogen production via ammonia boron hydrolysis.

[0099]

[0100] As shown in Table 2, the catalytic reaction rate of the Ni / D-TiOSO4 nanocatalyst prepared in Examples 1 and 5-8 for the hydrolysis of ammonia borane to produce hydrogen showed a trend of first increasing and then decreasing with the increase of TiOSO4 dosage. When the dosage was 40 mg, the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 showed the best performance for the hydrolysis of ammonia borane to produce hydrogen.

[0101] Example 11

[0102] The Ni / D-TiOSO4 nanocatalyst prepared in Example 1 of this invention and the various nanocatalysts prepared in Comparative Examples 1-4 are used to catalyze the hydrolysis of ammonia borane to produce hydrogen. The specific process is as follows:

[0103] The catalyst was placed in a 50 mL flask containing 4.7 mL of deionized water. The amount of catalyst was the same as that prepared in each example. 1 mmol of ammonia borane was added at 298 K atmospheric pressure to initiate the reaction. The hydrogen production performance graph and corresponding TOF values ​​are shown below. Figure 9 As shown in Table 3, the catalytic reaction results of the catalysts prepared in Example 1 and Comparative Examples 1-4 are shown in Table 3.

[0104] Table 3. Catalytic performance of various nanocatalysts prepared in Example 1 and Comparative Examples 1-4 for hydrogen production via ammonia borosilicate hydrolysis.

[0105]

[0106] Table 3 shows that the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 exhibits higher activity in the catalytic hydrolysis of ammonia borane to produce hydrogen than the catalysts prepared in Comparative Examples 1-4. The Ni nanocatalyst prepared in Comparative Example 1 shows very low activity, mainly due to the lack of a support, resulting in severe agglomeration of the metal nanoparticles and thus poor catalytic performance. No gas generation was detected in the TiOSO4 support prepared in Comparative Example 2, indicating that metallic Ni is the active center in the catalytic process. The Ni(PVP) + TiOSO4 nanocatalyst prepared in Comparative Example 3 shows lower catalytic activity than the Ni(PVP) + D-TiOSO4 prepared in Comparative Example 4, indicating that the defective structure of the support contributes to improving catalytic performance. However, the catalytic performance of Ni(PVP) + D-TiOSO4 is significantly lower than that of the Ni / D-TiOSO4 catalyst prepared by in-situ reduction, further demonstrating that strong metal-support interactions play a crucial role in enhancing catalytic activity.

[0107] Example 12

[0108] The specific process of using the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 of this invention to catalyze the hydrolysis of ammonia borane to produce hydrogen under different NaOH concentrations is as follows:

[0109] The catalyst was placed in a 50 mL flask containing 4.7 mL of deionized water. The amount of catalyst was the same as that prepared in each example. 1 mmol of ammonia borane was added at 298 K atmospheric pressure to initiate the reaction. The hydrogen production performance graph and corresponding TOF values ​​are shown below. Figure 10 As shown in Table 4, the conditions for catalyst preparation and the results of the catalytic reaction are as follows.

[0110] Table 4. Catalytic performance of Ni / D-TiOSO4 nanocatalysts prepared in Example 1 at different NaOH concentrations for hydrogen production from ammonia borane hydrolysis.

[0111]

[0112] Table 4 shows that the catalytic reaction rate of ammonia borane hydrolysis to hydrogen production catalyzed by Ni / D-TiOSO4 nanocatalyst first increases and then decreases with increasing NaOH concentration. At a NaOH concentration of 1.0 M, the prepared Ni / D-TiOSO4 nanocatalyst completes the decomposition and dehydrogenation of ammonia borane in just 0.24 min, with a conversion frequency (TOF) as high as 414.1 min. -1 This is mainly due to OH - The presence of NH4 in the reaction system can reduce the amount of NH4. + The concentration of NaOH shifts the hydrolysis reaction forward, thereby increasing catalytic activity. However, when the NaOH concentration exceeds 1.0 M, the hydrogen production rate does not increase synchronously, and the catalytic activity even shows a decreasing trend, indicating that excess OH... - This triggers passivation of active sites. Therefore, an appropriate amount of OH... - It can increase the rate of hydrogen production from the hydrolysis of NH3BH3.

[0113] Example 13

[0114] The specific process of catalyzing the hydrolysis of ammonia borane to produce hydrogen using the Ni / D-TiOSO4 nanocatalyst prepared in Examples 1-4 of this invention is as follows:

[0115] The catalyst was placed in a 50 mL flask containing 4.7 mL of deionized water. The amount of catalyst was the same as that prepared in each example. 1 mmol of ammonia borane was added at 298 K atmospheric pressure to initiate the reaction. The reaction was cycled 10 times. The hydrogen production performance graph and the cycle performance graph are shown below. Figure 11 As shown.

[0116] from Figure 11As can be seen, after the Ni / D-TiOSO4 nanocatalyst prepared in Example 1 was reused 10 times, the amount of gas produced by the hydrolysis of ammonia borane did not decrease, but the catalytic activity decreased slightly. Furthermore, compared with Ni / D-TiOSO4-x prepared with different NaBH4 addition amounts (where x refers to the amount of sodium borohydride added, x = 10 mg-40 mg), Ni / D-TiOSO4-30 exhibited superior cycling stability.

[0117] The excellent activity of the Ni / D-TiOSO4 nanocatalyst prepared in this invention is attributed to the strong metal-support interaction, the ultrafine Ni metal nanoparticles, and the introduction of oxygen vacancies that increase the electron density on the surface of the Ni nanoparticles.

[0118] In summary, this invention synthesizes TiOSO4 nanosheets using anhydrous titanium sulfate via a simple calcination method. Subsequently, NaBH4 is added to anchor Ni NPs onto the TiOSO4 nanosheets via a simple impregnation-reduction method, thus preparing a TiOSO4-supported Ni nanocatalyst (Ni / D-TiOSO4 nanocatalyst). This catalyst preparation method is simple to operate, low in cost, and the obtained catalyst has characteristics such as small particle size, multiple catalytic active sites, and high catalytic activity and stability, making it a promising catalyst for future development.

[0119] The embodiments of this application have been described above with reference to the accompanying drawings. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the core ideas of this application. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A Ni / D-TiOSO4 nanocatalyst, characterized in that, The Ni / D-TiOSO4 nanocatalyst comprises D-TiOSO4 nanosheets and Ni nanoparticles dispersed on the D-TiOSO4 nanosheets; the D-TiOSO4 nanosheets are oxygen-deficient TiOSO4 nanosheets. The average particle size of the Ni nanoparticles is 2.9 nm-3.6 nm, and the Ni content in the Ni / D-TiOSO4 nanocatalyst is 3.4 wt%-15.0 wt%. The preparation method of the Ni / D-TiOSO4 nanocatalyst includes the following steps: TiOSO4 powder was dispersed in water, then a nickel source precursor was added, and the mixture was ultrasonically treated to obtain a suspension. NaBH4 was added to the suspension to carry out a reduction reaction until no more bubbles were generated, thus obtaining the Ni / D-TiOSO4 nanocatalyst. The mass ratio of the TiOSO4 powder to the nickel source precursor is 10 mg-50 mg: 1.77 mg-8.85 mg; The ratio of NaBH4 to TiOSO4 powder is 10 mg-40 mg: 10 mg-50 mg; The TiOSO4 powder was prepared by the following steps: Titanium sulfate was placed in a muffle furnace and heated at a rate of 5 °C / min. -1 The temperature was raised to 500 °C and calcined for 4 h to obtain a light yellow TiOSO4 powder.

2. The Ni / D-TiOSO4 nanocatalyst according to claim 1, characterized in that, The nickel source precursor is NiCl2·6H2O.

3. The application of the Ni / D-TiOSO4 nanocatalyst according to claim 1 in the catalytic hydrolysis of ammonia borane to produce hydrogen.

4. The application according to claim 3, characterized in that, The Ni / D-TiOSO4 nanocatalyst uses NaOH as an additive in the catalytic hydrolysis of ammonia borane to produce hydrogen, wherein the concentration of NaOH is 0.25M-2.0M.

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