Ni-MoO x / HTO nanocatalyst and its preparation method and application

Abstract

This application belongs to the field of catalyst technology and specifically relates to a Ni-MoO x / HTO nanocatalyst and its preparation method and application. The method comprises mixing Cs2CO3 and TiO2, grinding, and calcining to obtain CsTO powder; then dispersing the mixture in water, adding a hydrochloric acid solution for reaction, filtering, washing, and drying to obtain an HTO carrier; dispersing the HTO carrier in water, then adding NiCl2·6H2O and Na2MoO4·2H2O, and ultrasonicating the mixture to obtain a suspension; adding a reducing agent to the suspension for reduction reaction until no bubbles are generated to obtain Ni-MoO x / HTO nanocatalyst. This catalyst exhibits excellent catalytic performance and outstanding cyclic stability in the hydrogen production reaction by hydrolysis of ammonia borane. Under additive-free conditions, the turnover frequency (TOF) of the catalytic reaction at 298 K reaches 143.9 min ‑1 .

Description

Technical Field

[0001] This application belongs to the field of catalyst technology and specifically relates to a Ni-MoO x / HTO nanocatalyst and its preparation method and application. Background Art

[0002] As an energy carrier with great application prospects, hydrogen has been widely used in fuel cell systems. How to safely and efficiently store and transport hydrogen is an important and challenging issue in the field of fuel cells. Ammonia borane (NH3BH3, AB) is considered to be a chemical hydrogen storage material with broad application prospects due to its high hydrogen content (19.6 wt%), long-term stability and non-toxicity. Under the action of a suitable catalyst, ammonia borane can release high-purity H2 under mild conditions (NH3BH3+ 2H2O → NH4 + + BO2 - + 3H2).

[0003] Nickel-based catalysts have excellent catalytic activity and have been shown to be ideal transition metal catalysts for the hydrolysis of ammonia borane to produce hydrogen. However, nickel-based catalysts are susceptible to particle aggregation during preparation and catalysis, resulting in a significant decrease in catalytic activity. Therefore, there is an urgent need to develop highly active and stable non-precious metal catalysts for the rapid hydrolysis of ammonia borane to produce hydrogen. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art and provide a Ni-MoO x / HTO nanocatalyst and its preparation method and application, specifically adopt the following technical solutions:

[0005] In the first aspect, the present invention provides a Ni-MoO x / The preparation method of HTO nanocatalyst comprises the following steps:

[0006] S1, mixing Cs2CO3 and TiO2, grinding, and calcining to obtain CsTO powder;

[0007] S2, dispersing the CsTO powder in water, then adding hydrochloric acid solution to react, filtering, washing, and drying to obtain an HTO carrier;

[0008] S3, dispersing the HTO support in water, then adding NiCl2·6H2O and Na2MoO4·2H2O, and sonicating to obtain a suspension;

[0009] S4, adding a reducing agent to the suspension to carry out a reduction reaction until no bubbles are generated to obtain the Ni-MoO x / HTO nanocatalyst.

[0010] In this paper, layered HTO was used as a carrier and Ni-MoO was prepared by a simple impregnation reduction method. x / HTO catalyst. The HTO support modulates the electron density of the loaded metal nanoparticles through metal-support electronic interaction (EMSI), optimizing the adsorption / desorption energy barrier at the active sites. The Mo species disperses the nanoparticles and reduces the crystallinity of the metal nanoparticles, increasing the electron density on the Ni metal surface and thereby improving the catalytic performance. Furthermore, the HTO support exhibits excellent chemical and thermal stability, maintaining structural integrity under harsh reaction conditions (such as strong acid / alkaline environments, high temperature and high pressure), further ensuring catalytic cycle stability.

[0011] As a further preferred embodiment, the molar ratio of the Cs2CO3, the TiO2 and the hydrochloric acid solution is 1:5.3:37.3.

[0012] As a further preferred embodiment, the usage ratio of the HTO support, the NiCl2·6H2O and the Na2MoO4·2H2O is 10 mg-50 mg: 11.88 mg: 0.001 mmol-0.005 mmol.

[0013] The amount of Na2MoO4·2H2O used in the above preparation process will affect the final prepared Ni-MoO x The catalytic performance of HTO nanocatalysts can be improved by changing the amount of dopant sodium molybdate (Na2MoO4·2H2O). x Precise control of doping amount. Mo species can disperse nanoparticles and reduce the crystallinity of metal nanoparticles, thereby increasing the electron density on the surface of metal Ni and thus improving the catalytic performance of the catalyst. When the amount of Na2MoO4·2H2O is 0.004 mmol, that is, MoO x The doping amount is 0.004 mmol, Ni-MoO x / HTO nanocatalyst showed the best performance for hydrogen production by hydrolysis of ammonia borane.

[0014] In addition, during the above preparation process, MoO x The doping amount and the amount of HTO carrier will affect the Ni-MoO x / HTO nanocatalyst catalytic activity. Under the condition of fixed HTO carrier dosage (40 mg), when MoO x The catalyst showed the best catalytic activity when the addition amount of MoO was 0.004 mmol. xThe doping amount is 0.004 mmol, and the continuous regulation of Ni nanoparticle loading is achieved by adjusting the amount of HTO carrier. The best catalytic performance is achieved when the added carrier mass is 40 mg (corresponding to a Ni loading of 6.8 wt%).

[0015] As a further preferred embodiment, the specific process of calcination is as follows:

[0016] Cs2CO3 and TiO2 were mixed and the powder obtained after grinding was placed in a muffle furnace at 5 ℃·min -1 The temperature was raised to 800 °C and calcined at a constant temperature, and then cooled to obtain CsTO powder.

[0017] As a further preferred embodiment, the constant temperature calcination time is 18 h-24 h.

[0018] As a further preferred embodiment, the reducing agent includes sodium borohydride.

[0019] In a second aspect, the present invention provides Ni-MoO x / HTO nanocatalyst is prepared by the above preparation method.

[0020] Ni-MoO of the present invention x / HTO nanocatalysts due to the Ni species and MoO x The synergistic effect between the Ni and HTO carriers, the ultrafine Ni metal nanoparticles and the excellent chemical and thermal stability of the HTO carriers give it excellent catalytic activity and cyclic stability, making it a catalyst with great development prospects.

[0021] As a further preferred embodiment, the Ni-MoO x The Ni loading amount in / HTO nanocatalyst is 5.5wt%-22.7 wt%.

[0022] According to the data of the embodiment of the present invention, when the Ni loading amount is 6.8 wt%, Ni-MoO x / HTO nanocatalyst reaches the maximum hydrogen production rate.

[0023] In a third aspect, the present invention provides the above-mentioned Ni-MoO x Application of HTO nanocatalyst in catalytic hydrolysis of ammonia borane to produce hydrogen.

[0024] As a further preferred embodiment, the Ni-MoO x The temperature for catalyzing the hydrolysis of ammonia borane to produce hydrogen by / HTO nanocatalyst is 288K-303K.

[0025] The beneficial effects of the present invention are:

[0026] (1) In this paper, layered HTO was used as a carrier and Ni-MoO was prepared by a simple impregnation reduction method. x / HTO catalyst. The HTO support modulates the electron density of the loaded metal nanoparticles through metal-support electronic interaction (EMSI), optimizing the adsorption / desorption energy barrier at the active sites. The Mo species disperses the nanoparticles and reduces the crystallinity of the metal nanoparticles, increasing the electron density on the Ni metal surface and thereby improving the catalytic performance. Furthermore, the HTO support exhibits excellent chemical and thermal stability, maintaining structural integrity under harsh reaction conditions (such as strong acid / alkaline environments, high temperature and high pressure), further ensuring catalytic cycle stability.

[0027] (2) Ni-MoO prepared by the present invention x / HTO catalyst showed excellent catalytic performance, 100% H2 selectivity and outstanding stability. x The TOF value of ammonia borane hydrolysis catalyzed by HTO at 298 K can reach 143.9 min. -1 .

[0028] (3) The catalyst provided by the present invention has the advantages of high efficiency, stability and low preparation cost, and is a catalyst with great development prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 The Ni-MoO prepared in Example 1 of the present invention is shown. x Transmission electron microscopy images of / HTO nanocatalysts (shown in (a)), Ni-MoO x The particle size statistics of the nanoparticles (shown in (b)), the transmission electron microscopy image of the Ni / HTO nanocatalyst prepared in Comparative Example 2 (shown in (c)), and the Ni-MoO x The particle size statistics of the nanoparticles (shown in (d)) and the Ni-MoO prepared in Comparative Example 3 x Transmission electron microscopy images of nanocatalysts (shown in (e)) and Ni-MoO x Particle size statistics of nanoparticles (shown in (f));

[0031] Figure 2 The Ni-MoO prepared in Example 1 of the present invention is shown.x / HTO nanocatalyst, Ni / HTO nanocatalyst prepared in Comparative Example 2 and Ni-MoO prepared in Comparative Example 3 x Ni 2p X-ray photoelectron spectroscopy (XPS) of nanocatalysts;

[0032] Figure 3 The Ni-MoO prepared in Example 1 of the present invention is shown. x Mo 3d X-ray photoelectron spectroscopy (XPS) of / HTO nanocatalyst;

[0033] Figure 4 The Ni-MoO prepared in Example 1 of the present invention is shown. x X-ray diffraction (XRD) patterns of the Ni / HTO nanocatalyst, the Ni / HTO nanocatalyst prepared in Comparative Example 2, and the HTO support prepared in Comparative Example 4;

[0034] Figure 5 The Ni-MoO prepared in Example 1 of the present invention is shown. x / Fourier transform infrared spectroscopy (FT-IR) of the HTO nanocatalyst and the HTO support prepared in Comparative Example 4;

[0035] Figure 6 The following are examples of the preparation of Ni-MoO in Examples 1 to 5 of the present invention. x Performance test diagram of / HTO nanocatalyst catalyzing the hydrolysis of ammonia borane to produce hydrogen at different Na2MoO4·2H2O dosages (shown in (a)) and the corresponding TOF value diagram (shown in (b));

[0036] Figure 7 The following are examples of the preparation of Ni-MoO in Examples 1, 6, and 9 of the present invention. x / HTO nanocatalyst catalyzing the hydrolysis of ammonia borane to produce hydrogen at different HTO carrier dosages (shown in (a)) and the corresponding TOF value graph (shown in (b));

[0037] Figure 8 The Ni-MoO prepared in Example 1 of the present invention is shown. x / HTO nanocatalyst and Ni nanocatalysts prepared in Comparative Examples 1 to 4, Ni / HTO nanocatalysts, Ni-MoO x Performance test diagram of the nanocatalyst and HTO support for catalytic hydrolysis of ammonia borane to produce hydrogen at 298 K (shown in (a)) and the corresponding TOF value diagram (shown in (b));

[0038] Figure 9 The Ni-MoO prepared in Example 1 of the present invention is shown. x / HTO nanocatalyst, Ni-CrO prepared in Comparative Example 5 x / HTO nanocatalyst and Ni-WO prepared in Comparative Example 6 x / HTO nanocatalyst catalyzing the hydrolysis of ammonia borane to produce hydrogen at 298 K (shown in (a)) and the corresponding TOF value (shown in (b));

[0039] Figure 10 The Ni-MoO prepared in Example 1 of the present invention is shown. x / HTO nanocatalyst, Ni-MoO prepared in Comparative Example 7 x / TiO2 (commercial) nanocatalyst and Ni-MoO prepared in Comparative Example 8 x Performance diagram of the α / CsTO nanocatalyst for catalytic hydrogen production by hydrolysis of ammonia borane at 298 K (shown in (a)) and the corresponding TOF value diagram (shown in (b));

[0040] Figure 11 The Ni-MoO prepared in Example 1 of the present invention is shown. x The performance test diagram (shown in (a)) and Arrhenius curve diagram (shown in (b)) of the Ni / HTO nanocatalyst for catalyzing the hydrolysis of ammonia borane to produce hydrogen at different temperatures, the performance test diagram (shown in (c)) and Arrhenius curve diagram (shown in (d)) of the Ni / HTO nanocatalyst prepared in Comparative Example 2 for catalyzing the hydrolysis of ammonia borane to produce hydrogen at different temperatures, and the Ni-MoO prepared in Comparative Example 3 x Performance test diagram of the nanocatalyst catalyzing the hydrolysis of ammonia borane to produce hydrogen at different temperatures (shown in (e)) and Arrhenius curve diagram (shown in (f));

[0041] Figure 12 The Ni-MoO prepared in Example 1 of the present invention is shown. x The cyclic stability test diagram of the Ni / HTO nanocatalyst catalyzing the hydrolysis of ammonia borane to produce hydrogen at 298 K (shown in (a)), the cyclic stability test diagram of the Ni / HTO nanocatalyst prepared in Comparative Example 2 catalyzing the hydrolysis of ammonia borane to produce hydrogen at 298 K (shown in (b)), and the cyclic stability test diagram of the Ni-MoO prepared in Comparative Example 3 x Cyclic stability test diagram of the nanocatalyst catalyzing the hydrolysis of ammonia borane to produce hydrogen at 298 K (as shown in (c)). DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0043] Example 1

[0044] A Ni-MoO x / The preparation method of HTO nanocatalyst specifically comprises the following steps:

[0045] (1) Preparation of HTO

[0046] Cs2CO3 (26.7 mmol) and TiO2 (141.5 mmol) were placed in an agate mortar at a molar ratio of 1:5.3 and ground thoroughly for 10-15 min until uniformly mixed. Subsequently, the obtained white powder was placed in a muffle furnace and heated at 5 °C·min -1 The temperature was raised to 800 °C at a heating rate of 100 °C and calcined at this temperature for 20 h. After the sample was cooled naturally, the above calcination process was repeated once to finally obtain white Cs2Ti6O 13 (denoted as CsTO) powder; then, the obtained CsTO was uniformly dispersed in 917 mL of deionized water, and 83 mL of 12 M hydrochloric acid solution was slowly added under continuous stirring conditions, and the reaction was carried out at room temperature for 24 h; after the reaction, the white precipitate was collected by vacuum filtration and repeatedly washed with deionized water until the filtrate was neutral, finally obtaining 40 mg of the target product HTO.

[0047] (2) Ni-MoO x Preparation of HTO nanocatalyst

[0048] 40 mg of HTO support prepared in step (1) was ultrasonically dispersed in 5 mL of deionized water for 5 min, and then NiCl2·6H2O (11.88 mg, 0.05 mmol) and Na2MoO4·2H2O (1.0 mg, 0.004 mmol) were added. The ultrasonic treatment was continued for 30 min to fully disperse the metal precursor. Subsequently, 30 mg of NaBH4 was added to the suspension for reduction. When no gas was generated, MoO x The doping amount is 0.004 mmol, and the HTO support is 40 mg (corresponding to a Ni loading of 6.8 wt%). x / HTO nanocatalyst.

[0049] Example 2

[0050] A Ni-MoO x The preparation method of the HTO nanocatalyst is similar to that in Example 1, except that the amount of Na2MoO4·2H2O in step (2) of Example 1 is changed from 0.004 mmol to 0.001 mmol, and the other steps are exactly the same to obtain MoO x The doping amount is 0.001 mmol, and the HTO support is 40 mg of Ni-MoO x / HTO nanocatalyst.

[0051] Example 3

[0052] A Ni-MoO x The preparation method of the HTO nanocatalyst is similar to that in Example 1, except that the amount of Na2MoO4·2H2O in step (2) of Example 1 is changed from 0.004 mmol to 0.002 mmol. The other steps are exactly the same to obtain MoO x The doping amount is 0.002 mmol, and the HTO support is 40 mg of Ni-MoO x / HTO nanocatalyst.

[0053] Example 4

[0054] A Ni-MoO x The preparation method of the HTO nanocatalyst is similar to that in Example 1, except that the amount of Na2MoO4·2H2O in step (2) of Example 1 is changed from 0.004 mmol to 0.003 mmol. The other steps are exactly the same to obtain MoO x The doping amount is 0.003 mmol, and the HTO support is 40 mg of Ni-MoO x / HTO nanocatalyst.

[0055] Example 5

[0056] A Ni-MoO x The preparation method of the HTO nanocatalyst is similar to that in Example 1, except that the amount of Na2MoO4·2H2O in step (2) of Example 1 is changed from 0.004 mmol to 0.005 mmol. The other steps are exactly the same to obtain MoO x The doping amount is 0.005 mmol, and the HTO support is 40 mg of Ni-MoO x / HTO nanocatalyst.

[0057] Example 6

[0058] A Ni-MoO x The preparation method of MoO / HTO nanocatalyst is similar to that in Example 1, except that the amount of HTO carrier in step (2) of Example 1 is changed from 40 mg to 50 mg. The other steps are exactly the same. x The doping amount is 0.004 mmol, and the HTO support is 50 mg (corresponding to a Ni loading of 5.5 wt%). x / HTO nanocatalyst.

[0059] Example 7

[0060] A Ni-MoO x The preparation method of MoO / HTO nanocatalyst is similar to that in Example 1, except that the amount of HTO carrier in step (2) of Example 1 is changed from 40 mg to 30 mg. The other steps are exactly the same. x The doping amount is 0.004 mmol, and the HTO support is 30 mg (corresponding to a Ni loading of 8.9 wt%). x / HTO nanocatalyst.

[0061] Example 8

[0062] A Ni-MoO x The preparation method of MoO / HTO nanocatalyst is similar to that in Example 1, except that the amount of HTO carrier in step (2) of Example 1 is changed from 40 mg to 20 mg. The other steps are exactly the same. x The doping amount is 0.004 mmol, and the HTO support is 20 mg (corresponding to a Ni loading of 12.8 wt%). x / HTO nanocatalyst.

[0063] Example 9

[0064] A Ni-MoO x The preparation method of MoO / HTO nanocatalyst is similar to that in Example 1, except that the amount of HTO carrier in step (2) of Example 1 is changed from 40 mg to 10 mg. The other steps are exactly the same. x The doping amount is 0.004 mmol, and the HTO support is 10 mg (corresponding to a Ni loading of 22.7 wt%). x / HTO nanocatalyst.

[0065] Comparative Example 1

[0066] A method for preparing a Ni nanocatalyst is similar to the method of step (2) in Example 1, except that the HTO carrier and the Na2MoO4·2H2O dopant are not added in step (2). The other steps are exactly the same as step (2) in Example 1 to obtain a Ni nanocatalyst.

[0067] Comparative Example 2

[0068] A method for preparing a Ni / HTO nanocatalyst is similar to the method in Example 1, except that the Na2MoO4·2H2O dopant is not added in step (2). The other steps are exactly the same as those in Example 1 to obtain a Ni / HTO nanocatalyst.

[0069] Comparative Example 3

[0070] A Ni-MoO x The preparation method of the nanocatalyst is similar to the method of step (2) in Example 1, except that the HTO carrier is not added in step (2). The other steps are exactly the same as step (2) in Example 1 to obtain Ni-MoO x Nanocatalyst.

[0071] Comparative Example 4

[0072] A method for preparing an HTO carrier, wherein the preparation method is identical to the method in step (1) of Example 1, and 40 mg of the target product HTO is obtained.

[0073] Comparative Example 5

[0074] A Ni-CrO x The preparation method of Ni-CrO nanocatalyst is similar to that of Example 1, except that Na2MoO4·2H2O in step (2) is replaced by Cr(NO3)3·6H2O. The other steps are exactly the same as those of Example 1 to obtain Ni-CrO x / HTO nanocatalyst.

[0075] Comparative Example 6

[0076] A Ni-WO x The preparation method of Ni-WO nanocatalyst is similar to that of Example 1, except that Na2MoO4·2H2O in step (2) is replaced by Na2WO4·2H2O. The other steps are exactly the same as those of Example 1 to obtain Ni-WO nanocatalyst. x / HTO nanocatalyst.

[0077] Comparative Example 7

[0078] A Ni-MoO x / TiO2 (commercial) nanocatalyst preparation method, the preparation method is similar to the method of Example 1, the only difference is that the HTO carrier in step (2) is replaced by TiO2 (commercial) carrier, the other steps are exactly the same as Example 1, to obtain Ni-MoO x / TiO2 (commercial) nanocatalyst.

[0079] Comparative Example 8

[0080] A Ni-MoO x The preparation method of Ni-MoO / CsTO nanocatalyst is similar to that of Example 1, except that the HTO carrier in step (2) is replaced with a CsTO carrier. The other steps are exactly the same as those of Example 1 to obtain Ni-MoO x / CsTO nanocatalyst.

[0081] The relevant characterization data of some materials prepared in the above examples are as follows:

[0082] Figure 1 The Ni-MoO prepared in Example 1 of the present invention is shown. x Transmission electron microscopy images of / HTO nanocatalysts (shown in (a)) and Ni-MoO x The particle size statistics of the nanoparticles (shown in (b)), the transmission electron microscopy image of the Ni / HTO nanocatalyst prepared in Comparative Example 2 (shown in (c)), and the Ni-MoO x The particle size statistics of the nanoparticles (shown in (d)) and the Ni-MoO prepared in Comparative Example 3 x Transmission electron microscopy images of nanocatalysts (shown in (e)) and Ni-MoO x The particle size statistics of nanoparticles (shown in (f)); and Figure 1 It can be seen that Ni-MoO x Ni-MoO / HTO nanocatalyst x The average particle size of the particles is 2.7 nm, and the non-supported Ni-MoO x The nanoparticles have a large average particle size of 3.5 nm, while the Ni particle size of the single metal Ni / HTO is 4.2 nm. This phenomenon confirms that the HTO support inhibits metal agglomeration through spatial confinement effect, while MoO x The introduction of further refines the Ni grain size through electronic synergy. This synergistic effect between the support and the active component provides a dual regulation mechanism for the formation of highly dispersed small-sized metal nanoparticles.

[0083] Figure 2 The Ni-MoO prepared in Example 1 of the present invention is shown. x / HTO nanocatalyst, Ni / HTO nanocatalyst prepared in Comparative Example 2 and Ni-MoO prepared in Comparative Example 3 x Ni 2p X-ray photoelectron spectroscopy (XPS) of nanocatalysts; and by Figure 2 It can be seen that compared with Comparative Examples 2 and 3, the Ni-MoO x Ni / HTO nanocatalyst 0 The binding energy of Ni-MoO shows a negative shift of 0.3 eV-0.4 eV, indicating that x / HTO contains Ni from MoO x and the carrier HTO. Electrons are generated on Ni, MoO x The transfer between HTO and the other three is beneficial to the hydrolysis of NH3BH3.

[0084] Figure 3 The Ni-MoO prepared in Example 1 of the present invention is shown. x Mo 3d X-ray photoelectron spectroscopy (XPS) of / HTO nanocatalysts; and by Figure 3 It can be seen that the characteristic signals of the binding energy at 227.2 eV and 230.9 eV are Mo 3+ The characteristic signals of Mo binding energy at 229.0 eV and 232.3 eV are 4+ The characteristic signals of Mo binding energy at 234.3 eV and 235.7 eV are 6+ , indicating that the catalyst Ni-MoO x / MoO in HTO x As an electron modulation medium in a non-stoichiometric form.

[0085] Figure 4 The Ni-MoO prepared in Example 1 of the present invention is shown. x / HTO nanocatalyst, Ni / HTO nanocatalyst prepared in Comparative Example 2 and HTO carrier prepared in Comparative Example 4; and Figure 4 It can be seen that in Ni-MoO x In the Ni / HTO and Ni / HTO samples, the complete retention of the HTO characteristic diffraction peaks indicates that the crystal framework of the support was not destroyed during the loading process of metal nanoparticles.

[0086] Figure 5 The Ni-MoO prepared in Example 1 of the present invention is shown. x / HTO nanocatalyst and the HTO carrier prepared in Comparative Example 4; and Figure 5 It can be seen that Ni-MoO x / HTO and HTO matrix have no significant shift in characteristic vibration frequency, peak shape and relative intensity, indicating that Ni-MoO x The nanoparticle loading process did not cause significant distortion of the support skeleton structure, which is consistent with the X-ray diffraction (XRD) analysis results, confirming the structural stability of the HTO support in the composite catalyst system.

[0087] Example 10

[0088] The Ni-MoO prepared by Examples 1 to 5 of the present invention x / HTO nanocatalyst catalyzes the hydrolysis of ammonia borane to produce hydrogen, and the specific process is as follows:

[0089] The catalyst was placed in a 50 mL flask containing 4.46 mL of deionized water. The amount of catalyst was the amount of catalyst prepared in each example. 1 mmol of ammonia borane was added at 298 K and normal pressure to react. The hydrogen production performance diagram and the corresponding TOF value are shown in FIG. Figure 6 The conditions for preparing the catalysts of Examples 1 to 5 and the results of the catalytic reactions are shown in Table 1.

[0090] Table 1 Preparation of Ni-MoO in Examples 1-5 x / HTO nanocatalyst catalytic performance of ammonia borane hydrolysis to produce hydrogen

[0091]

[0092] As shown in Table 1, the Ni-MoO prepared in Examples 1 to 5 x Under the condition of fixed HTO carrier dosage (40 mg), the reaction rate of catalytic ammonia borane hydrolysis to produce hydrogen showed a trend of first increasing and then decreasing with the increase of Na2MoO4·2H2O dosage. When the dosage was 0.004 mmol, the Ni-MoO4 prepared in Example 1 x / HTO nanocatalysts showed the best performance for hydrogen production by hydrolysis of ammonia borane. This indicates that changing the amount of dopant sodium molybdate (Na2MoO4·2H2O) can achieve the effect of MoO x Precise control of doping amount. Mo species can disperse nanoparticles and reduce the crystallinity of metal nanoparticles, thereby increasing the electron density on the surface of metal Ni and thus improving the catalytic activity, making the final Ni-MoO x / HTO nanocatalysts have different catalytic performances in the reactions.

[0093] Example 11

[0094] Ni-MoO prepared by Example 1, Example 6-Example 9 of the present invention x / HTO nanocatalyst catalyzes the hydrolysis of ammonia borane to produce hydrogen, and the specific process is as follows:

[0095] The catalyst was placed in a 50 mL flask containing 4.46 mL of deionized water. The amount of catalyst was the amount of catalyst prepared in each example. 1 mmol of ammonia borane was added at 298 K and normal pressure to react. The hydrogen production performance diagram and the corresponding TOF value are shown in FIG. Figure 7 The conditions for preparing the catalysts of Example 1, Example 6-Example 9 and the results of the catalytic reactions are shown in Table 2.

[0096] Table 2 Preparation of Ni-MoO in Example 1, Example 6-Example 9 x / HTO nanocatalyst catalytic performance of ammonia borane hydrolysis to produce hydrogen

[0097]

[0098] As shown in Table 2, the Ni-MoO prepared in Examples 1, 6-9 x / HTO nanocatalyst fixed MoO x Under the condition of a doping amount of 0.004 mmol, the catalytic reaction rate of catalyzing the hydrolysis of ammonia borane to produce hydrogen shows a trend of first increasing and then decreasing with the dosage of the carrier HTO. When the dosage is 40 mg (corresponding to a Ni loading of 6.8 wt%), the catalyst reaches the maximum hydrogen production rate.

[0099] Example 12

[0100] The Ni-MoO prepared in Example 1 of the present invention x The HTO nanocatalyst and the nanocatalysts prepared in Comparative Examples 1 to 4 catalyzed the hydrolysis of ammonia borane to produce hydrogen. The specific process is as follows:

[0101] The catalyst was placed in a 50 mL flask containing 4.46 mL of deionized water. The amount of catalyst was the amount of catalyst prepared in each example. 1 mmol of ammonia borane was added at 298 K and normal pressure to react. The hydrogen production performance diagram and the corresponding TOF value are shown in FIG. Figure 8 The conditions for catalyst preparation and the results of the catalytic reaction are shown in Table 3.

[0102] Table 3 Performance of various nanocatalysts prepared in Example 1 and Comparative Examples 1-4 for catalytic hydrogen production by hydrolysis of ammonia borane

[0103]

[0104] It can be seen from Table 3 that the Ni-MoO prepared in Example 1 xThe activity of the HTO nanocatalysts in catalyzing the hydrolysis of ammonia borane to produce hydrogen was higher than that of the catalysts prepared in Comparative Examples 1 to 4. This performance improvement is attributed to the interaction between the HTO support and the MoO x Synergistic effect of additives: HTO inhibits metal agglomeration through two-dimensional confinement, MoO x The electronic structure of Ni is optimized through electronic modulation, which jointly promotes the efficient utilization of active sites. Among them, no gas generation was detected in the HTO carrier prepared in Comparative Example 4, indicating that metallic Ni is the core active site of the hydrolysis reaction.

[0105] Example 13

[0106] Ni-MoO prepared in Example 1 of the present invention x The nanocatalysts prepared by the / HTO nanocatalyst, Comparative Example 5 and Comparative Example 6 catalyze the hydrolysis of ammonia borane to produce hydrogen. The specific process is as follows:

[0107] The catalyst was placed in a 50 mL flask containing 4.46 mL of deionized water. The amount of catalyst was the amount of catalyst prepared in each example. 1 mmol of ammonia borane was added at 298 K and normal pressure to react. The hydrogen production performance diagram and the corresponding TOF value are shown in FIG. Figure 9 The conditions for catalyst preparation and the results of the catalytic reaction are shown in Table 4.

[0108] Table 4 Performance of each nanocatalyst prepared in Example 1, Comparative Example 5 and Comparative Example 6 for catalytic hydrolysis of ammonia borane to produce hydrogen

[0109]

[0110] It can be seen from Table 4 that the Ni-MoO prepared in Example 1 x / HTO nanocatalyst showed the highest catalytic activity, while CrO x with WO x The activity of Ni / HTO was not significantly improved. x There is a good synergistic effect between NPs and HTO.

[0111] Example 14

[0112] Ni-MoO prepared in Example 1 of the present invention x The nanocatalysts prepared by the / HTO nanocatalyst, Comparative Example 7 and Comparative Example 8 catalyze the hydrolysis of ammonia borane to produce hydrogen. The specific process is as follows:

[0113] The catalyst was placed in a 50 mL flask containing 4.46 mL of deionized water. The amount of catalyst was the amount of catalyst prepared in each example. 1 mmol of ammonia borane was added at 298 K and normal pressure to carry out the reaction. The hydrogen production performance graph and the corresponding TOF value graph are shown in FIG. Figure 10 The conditions for catalyst preparation and the results of the catalytic reaction are shown in Table 5.

[0114] Table 5 Performance of each nanocatalyst prepared in Example 1, Comparative Example 7 and Comparative Example 8 for catalytic hydrolysis of ammonia borane to produce hydrogen

[0115]

[0116] It can be seen from Table 5 that Ni-MoO loaded on commercial TiO2 and CsTO x The catalytic activity of nanoparticles is higher than that of Ni-MoO x / HTO is much lower. This result further verifies that Ni-MoO x There is a good synergistic effect between NPs and HTO.

[0117] Example 15

[0118] Ni-MoO prepared in Example 1 of the present invention x The nanocatalysts prepared by the HTO nanocatalyst, comparative example 2 and comparative example 3 catalyze the hydrolysis of ammonia borane to produce hydrogen at different temperatures. The specific process is as follows:

[0119] The catalyst was placed in a 50 mL flask containing 4.46 mL of deionized water. The amount of catalyst was the amount of catalyst prepared in each example. 1 mmol of ammonia borane was added at 288 K, 293 K, and 303 K under normal pressure to carry out the reaction. The hydrogen production performance diagram and Arrhenius curve are shown in FIG. Figure 11 The conditions for catalyst preparation and the results of the catalytic reaction are shown in Table 6.

[0120] Table 6 Performance of various nanocatalysts prepared in Example 1, Comparative Example 2 and Comparative Example 3 for catalytic ammonia borane hydrolysis to produce hydrogen at different temperatures

[0121]

[0122] As shown in Table 6, the Ni-MoO x The apparent activation energy (Ea) of the HTO / HTO catalytic system is 43.8 kJ·mol -1 For comparison, the unsupported Ni-MoO x The Ea of NPs and Ni / HTO are 64.1 kJ·mol -1 and 71.9 kJ·mol -1 The results show that the activation energy decrease trend is consistent with the catalytic activity improvement law, indicating that Ni NPs, MoOx The synergistic effect between the HTO support and the ammonia borane can effectively reduce the energy barrier of the hydrolysis reaction.

[0123] Example 16

[0124] Ni-MoO prepared in Example 1 of the present invention x The nanocatalysts prepared by the / HTO nanocatalyst, Comparative Example 2 and Comparative Example 3 catalyze the hydrolysis of ammonia borane to produce hydrogen, and the specific process is as follows:

[0125] The catalyst was placed in a 50 mL flask containing 4.46 mL of deionized water. The amount of catalyst was the amount of catalyst prepared in each example. 1 mmol of ammonia borane was added at 298 K and normal pressure to carry out the reaction. The reaction was repeated 10 times. The hydrogen production performance diagram and the cycle performance diagram are shown in FIG. Figure 12 shown.

[0126] from Figure 12 It can be seen that the Ni-MoO prepared in Example 1 x After being reused 10 times, the amount of gas produced by the hydrolysis of ammonia borane by the / HTO nanocatalyst did not decrease, and its activity remained good, and was significantly better than that of Ni / HTO and Ni-MoO x catalyst. This difference confirms that MoO x The simultaneous introduction of doping with HTO supports not only improves the catalytic activity of the catalyst, but also enhances the cyclic stability of the catalyst. By improving the stability of the catalyst, the utilization rate is increased, saving costs while reducing resource consumption.

[0127] Ni-MoO prepared by the present invention x The excellent activity and stability of the HTO nanocatalyst are attributed to the interaction of Ni species with MoO x and the synergistic effect between the HTO support, the ultrafine Ni metal nanoparticles and the excellent chemical and thermal stability of the HTO support.

[0128] In summary, the method for preparing the catalyst of the present invention is simple to operate and low in cost. The obtained catalyst has the characteristics of small particle size, high electron density of metal Ni, and high catalytic activity and stability, and is a catalyst with great development prospects.

[0129] The embodiments of the present application are described above in conjunction with the accompanying drawings. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the core idea of ​​the present application, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present application and the claims, all of which are within the protection of the present application.

Claims

1. A Ni-MoO x / The preparation method of HTO nanocatalyst is characterized in that: The following steps are involved: S1, mixing Cs2CO3 and TiO2, grinding, and calcining to obtain CsTO powder; S2, dispersing the CsTO powder in water, then adding hydrochloric acid solution to react, filtering, washing, and drying to obtain an HTO carrier; S3, dispersing the HTO support in water, then adding NiCl2·6H2O and Na2MoO4·2H2O, and sonicating to obtain a suspension; S4, adding a reducing agent to the suspension to carry out a reduction reaction until no bubbles are generated to obtain the Ni-MoO x / HTO nanocatalyst; The molar ratio of the Cs2CO3, the TiO2 and the hydrochloric acid solution is 1:5.3:37.3; The usage ratio of the HTO carrier, the NiCl2·6H2O and the Na2MoO4·2H2O is 10 mg-50 mg: 11.88mg: 0.001 mmol-0.005 mmol; The specific process of the calcination is as follows: Cs2CO3 and TiO2 were mixed and the powder obtained after grinding was placed in a muffle furnace at 5 ℃·min -1 The temperature was raised to 800 °C and calcined at a constant temperature, and then cooled to obtain CsTO powder.

2. The preparation method according to claim 1, characterized in that The constant temperature calcination time is 18 h-24 h.

3. The preparation method according to claim 1, characterized in that The reducing agent includes sodium borohydride.

4. A Ni-MoO x / HTO nanocatalyst, characterized in that The invention is prepared by the preparation method according to any one of claims 1 to 3.

5. Ni-MoO according to claim 4 x / HTO nanocatalyst, characterized in that The Ni-MoO x The Ni loading amount in / HTO nanocatalyst is 5.5 wt%-22.7 wt%.

6. Ni-MoO according to any one of claims 4 to 5 x Application of HTO nanocatalyst in catalytic hydrolysis of ammonia borane to produce hydrogen.

7. The use according to claim 6, characterized in that The Ni-MoO x The temperature of hydrogen production by hydrolysis of ammonia borane catalyzed by / HTO nanocatalyst is 288K-303K.

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