A 10% Co@MoS2 / MoO 3-x Application of C3N4 photocatalyst in photocatalytic hydrolysis of ammonia borane for hydrogen production

Abstract

This invention discloses a 10% Co@MoS2 / MoO metal-free method. 3‑x The preparation of MoS2 / MoO2 composite materials and their application in green energy development were carried out. A Z-shaped heterojunction, S-vacancy-enriched MoS2 / MoO2 composite material was constructed using a simple calcination and high-temperature reduction strategy. 3‑x 10% Co@MoS2 / MoO2 with features such as hybrid structure and Co nanoparticle loading 3‑x The / C3N4 composite material exhibits properties beneficial for the photocatalytic hydrolysis of ammonia borane (AB). 10% Co@MoS2 / MoO 3‑x / C3N4 can achieve a melting point of 130.0 min under visible light irradiation. ‑1 The hydrolysis efficiency of ammonia borane in TOF (Time-of-Flight) reactors is closely related to the Z-type heterojunction. The Z-type heterojunction improves charge transfer efficiency and promotes redox activity, resulting in a higher MoS2 / MoO2 ratio. 3‑x The hybrid structure promotes positive conduction band shift and water activation, and the S-vacancy construction enhances substrate and water adsorption capacity.

Description

Technical Field

[0001] This invention relates to a 10% Co@MoS2 / MoO 3-x Application of C3N4 photocatalyst in photocatalytic hydrolysis of ammonia borane to produce hydrogen. Background Technology

[0002] The development of low-carbon, clean, and renewable new energy sources is an inevitable path. Among numerous new energy sources, hydrogen is considered the most promising energy source of the 21st century due to its high efficiency, cleanliness, and sustainability. Furthermore, hydrogen energy is a globally recognized clean energy source, contributing to solving the energy crisis, achieving energy transition, and curbing global warming and environmental pollution. Therefore, the development and utilization of hydrogen energy has attracted worldwide attention. The difficulty in storing hydrogen in compressed or liquefied forms has become a major obstacle to its utilization. Solid-state hydrogen storage is a method that utilizes the physical or chemical changes between hydrogen storage materials and hydrogen to store hydrogen. Among these, ammonia borane (NH3BH3, AB) is considered one of the most promising hydrogen storage materials due to its high hydrogen content of 19.6 wt%. Under appropriate catalysis, the hydrolysis of ammonia borane can proceed rapidly to produce hydrogen. Many noble metals and their alloy catalysts have been extensively studied in the catalytic hydrolysis of ammonia borane to produce hydrogen, exhibiting good activity in AB hydrolysis. However, the high cost of noble metal-based catalysts is a major obstacle to their commercial application. To overcome the high cost barrier of precious metal-based catalysts, many researchers are dedicated to finding cheaper and more efficient alternative materials.

[0003] Among them, non-noble metal materials such as transition metal sulfides and nitrides possess abundant catalytic active sites and low preparation costs, exhibiting catalytic performance comparable to or even better than that of noble metals. Furthermore, the design and preparation of some nanostructures, porous materials, and composite materials can further improve the efficiency and stability of AB water splitting for hydrogen production, making them ideal photocatalytic materials. Summary of the Invention

[0004] This invention provides a 10% Co@MoS2 / MoO 3-x The C3N4 photocatalyst is used in the photocatalytic hydrolysis of ammonia borane to produce hydrogen. This invention provides a simple and economical preparation method for the photocatalytic hydrolysis of ammonia borane to produce hydrogen. 10% Co@MoS2 / MoO 3-x The C3N4 photocatalyst for the efficient hydrolysis of ammonia borane to produce hydrogen under visible light not only avoids the use of precious metals and has mild reaction conditions and high hydrogen evolution activity, but also significantly improves its TOF value compared to the dark reaction.

[0005] The technical solution adopted is to construct 10% Co@MoS2 / MoO through a simple calcination and high-temperature reduction strategy. 3-xThe / C3N4 composite material exhibits Z-shaped heterojunction formation. The Z-shaped heterojunction enhances charge transfer efficiency and promotes redox capabilities. (MoS2 / MoO) 3-x Hybridization promotes positive conduction band shift and water activation, while S-vacancy construction enhances substrate and water adsorption capacity, further improving the performance of ammonia borane (AB) hydrolysis. The photocatalytic hydrolysis of ammonia borane to produce hydrogen involves: placing a certain amount of photocatalyst and an aqueous solution of CoCl2•6H2O in a two-necked flask with stirring and loading; adding a certain amount of nano-metal reducing agent NaBH4 and an aqueous solution of the substrate NH3BH3 to the mixture; and initiating the catalytic reaction immediately under 298 K illumination. This catalyst preparation method is simple and easy to operate, and can be used for efficient photocatalytic hydrolysis of ammonia borane to produce hydrogen under mild reaction conditions. Under optimized conditions, the TOF can reach 130.0 min. -1 Moreover, the catalyst is easy to recycle.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] Different composite photocatalysts are prepared by methods comprising the following steps:

[0008] 1) The preparation method of the catalytic material is as follows:

[0009] Preparation of C3N4: 5.0 g of melamine was heated to 500 °C at a rate of 5 °C / min and held for 2 h to synthesize C3N4. The light yellow sample was collected and ground into powder.

[0010] Preparation of MoS2: First, 0.48 g NaMoO4·2H2O and 0.76 g thiourea were dissolved in 40 mL of deionized water. The mixture was effectively dispersed by magnetic stirring for 30 minutes. The uniform and transparent solution was loaded into a high-pressure reactor with a 50 mL polytetrafluoroethylene liner and treated at 240 °C for 22 hours. The black precipitate was collected by centrifugation and washed with deionized water and ethanol. Then, it was dried in an oven at 85 °C for 24 hours to obtain a black MoS2 sample.

[0011] Preparation of MoS2 / C3N4: 0.495 g C3N4 and 0.055 g MoS2 (10 wt%) were dispersed in deionized water to form a mixture. The resulting solution was then vigorously stirred for 1 hour, followed by ultrasonic dispersion for 2 hours to obtain a homogeneous mixture. This mixture was dried at 80 °C for 12 hours to remove the solvent. The resulting product was then processed in 15 mL / min... −1 The mixture was calcined at 300 °C for 2 hours under a nitrogen flow to further consolidate the heterojunction interface, and finally a MoS2 / C3N4 heterojunction composite material with a MoS2 mass ratio of 10 wt% was obtained.

[0012] Preparation of MoO3 / C3N4: 1.98 g of C3N4 and 0.22 g of MoO3 (purchased directly) at a mass ratio of 10 wt% were uniformly dispersed in 50 mL of ethanol by ultrasonication for 2 hours. The mixture was then evaporated at 75 °C to remove the ethanol, followed by drying at 100 °C for 12 hours. The resulting powder was ground and then calcined in a muffle furnace at 300 °C for 4 hours. After cooling to room temperature, the target product was obtained.

[0013] Preparation of 10% Co@C3N4: 18.0 mg C3N4 and 0.034 mmol CoCl2•6H2O were dissolved in 1.0 mL of water in a double-necked flask and stirred for 5 h. 1.0 mL of 0.068 mmol NaBH4 aqueous solution was added to the mixture, and the mixture was stirred for reduction for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and dried overnight in a vacuum oven at 60 °C.

[0014] Preparation of 10% Co@MoS2+C3N4: 1.0 mL of an aqueous solution of 1.8 mg MoS2, 16.2 mg C3N4, and 0.034 mmol CoCl2•6H2O was stirred in a double-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was then added to the mixture, and the mixture was stirred for reduction for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and then dried overnight in a vacuum oven at 60 °C.

[0015] Preparation of 10% Co@MoO3+C3N4: 1.0 mL of an aqueous solution of 1.8 mg MoO3, 16.2 mg C3N4, and 0.034 mmol CoCl2•6H2O was stirred in a double-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was then added to the mixture, and the mixture was stirred for reduction for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and then dried overnight in a vacuum oven at 60 °C.

[0016] MoS2 / MoO 3-x Preparation of / C3N4: 1.0 mL of an aqueous solution of 18.0 mg MoS2 / C3N4 was stirred in a double-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was added to the mixture, and the mixture was reduced at 60°C for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and then dried overnight in a vacuum oven at 60°C.

[0017] 10% Co@MoS2 / MoO 3-xPreparation of / C3N4: 18.0 mg MoS2 / C3N4 and 1.0 mL of an aqueous solution of 0.034 mmol CoCl2•6H2O were stirred in a two-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was added to the mixture, and the mixture was reduced at 60°C for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and dried overnight in a vacuum oven at 60°C. The reaction was then carried out with 10% Co@MoS2 / MoO2. 3-x A similar process to that used for C3N4 synthesized 5% Co@MoS2 / MoO. 3-x / C3N4 and 15% Co@MoS2 / MoO 3-x / C3N4.

[0018] Preparation of 10% Co@MoO3 / C3N4: 18.0 mg MoO3 / C3N4 and 1.0 mL of an aqueous solution of 0.034 mmol CoCl2•6H2O were stirred in a double-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was added to the mixture, and the mixture was stirred for reduction for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and then dried overnight in a vacuum oven at 60 °C.

[0019] The steps for efficient hydrogen production are as follows:

[0020] 10.0 mg 10% Co@MoS2 / MoO 3-x The / C3N4 catalyst was added to a two-necked flask. 1.0 mL of an aqueous solution of 1.0 mmol NH3BH3 was added to the flask, and the catalytic reaction was immediately initiated at 298 K. The amount of gas generated was monitored by water displacement during the catalytic reaction. To compare the effects of different proportions of Co loading and no Co loading on the hydrogen evolution performance of the catalyst, the 5% Co@MoS2 / MoO2 catalyst was tested using the same method. 3-x / C3N4、10%Co@MoS2 / MoO 3-x / C3N4、15%Co@MoS2 / MoO 3-x / C3N4、10% Co@MoS2+C3N4、10% Co@C3N4、MoS2 / MoO 3-x / C3N4、10% Co@MoO 3-x Hydrogen evolution performance of / C3N4, MoO3 / C3N4, and 10% Co@MoO3+C3N4 catalysts. Attached Figure Description

[0021] Figure 1The C3N4, MoS2, MoS2 / C3N4, and 10% Co@MoS2 / MoO prepared in Example 1 are examples of these compounds. 3-x X-ray diffraction (XRD) spectrum of the C3N4 photocatalytic material.

[0022] Figure 2 middle, Figure 2 a is a transmission electron microscope (TEM) image of MoS2 / C3N4 prepared in Example 1. Figure 2 b is a high-resolution transmission electron microscope (HRTEM) image of MoS2 / C3N4. Figure 2 c is the elemental mapping (EDS) of MoS2 / C3N4; Figure 2 d is 10% Co@MoS2 / MoO 3-x Transmission electron microscopy (TEM) of / C3N4. Figure 2 e is 10% Co@MoS2 / MoO 3-x High-resolution transmission electron microscopy (HRTEM) of / C3N4.

[0023] Figure 3 This is from Implementation Case 1, which prepared 10% Co@MoS2 / MoO 3-x X-ray photoelectron spectroscopy (XPS) of C3N4: 10%Co@MoS2 / MoO 3-x The full spectrum of / C3N4 ( Figure 3 a), C 1s ( Figure 3 b), N 1s ( Figure 3 c), Mo 3d ( Figure 3 d), S 2p ( Figure 3 e), O1s ( Figure 3 f), Co 2p ( Figure 3 g).

[0024] Figure 4 The photocatalysts prepared in Example 1 are C3N4, MoS2 / C3N4, and 10% Co@MoS2 / MoO. 3-x The transient photocurrent density of / C3N4 as a function of time ( Figure 4 a) Electrochemical impedance spectroscopy (EIS) Figure 4 b) and photoluminescence spectrum (PL, Figure 4 c). Detailed Implementation

[0025] The invention will now be described in detail with reference to specific implementation examples.

[0026] Implementation Case 1:

[0027] The preparation method of the catalytic material is as follows:

[0028] Preparation of C3N4: 5.0 g of melamine was heated to 500 °C at a rate of 5 °C / min and held for 2 h to synthesize C3N4. The light yellow sample was collected and ground into powder.

[0029] Preparation of MoS2: First, 0.48 g NaMoO4·2H2O and 0.76 g thiourea were dissolved in 40 mL of deionized water. The mixture was effectively dispersed by magnetic stirring for 30 minutes. The uniform and transparent solution was loaded into a high-pressure autoclave with a 50 mL polytetrafluoroethylene liner and treated at 240 °C for 22 hours. The black precipitate was collected by centrifugation and washed with deionized water and ethanol. Then, it was dried in an oven at 85 °C for 24 hours to obtain a black MoS2 sample.

[0030] Preparation of MoS2 / C3N4: 0.495 g C3N4 and 0.055 g MoS2 (10 wt%) were dispersed in deionized water to form a mixture. The resulting solution was then vigorously stirred for 1 hour, followed by ultrasonic dispersion for 2 hours to obtain a homogeneous mixture. This mixture was dried at 80 °C for 12 hours to remove the solvent. The resulting product was then processed in 15 mL / min... −1 The heterojunction was calcined at 300 °C for 2 hours under a nitrogen flow to further consolidate the heterojunction interface, and finally a MoS2 / C3N4 heterojunction composite material with a MoS2 mass ratio of 10 wt% was obtained.

[0031] Preparation of MoO3 / C3N4: 1.98 g of C3N4 and 0.22 g of MoO3 (purchased directly) at a mass ratio of 10 wt% were uniformly dispersed in 50 mL of ethanol by ultrasonication for 2 hours. The mixture was then evaporated at 75 °C to remove the ethanol, followed by drying at 100 °C for 12 hours. The resulting powder was ground and then calcined in a muffle furnace at 300 °C for 4 hours. After cooling to room temperature, the target product was obtained.

[0032] Preparation of 10% Co@C3N4: 18.0 mg C3N4 and 1.0 mL of an aqueous solution of 0.034 mmol CoCl2•6H2O were stirred in a double-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was added to the mixture, and the mixture was stirred for reduction for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and dried overnight in a vacuum oven at 60 °C.

[0033] Preparation of 10% Co@MoS2+C3N4: 1.0 mL of an aqueous solution of 1.8 mg MoS2, 16.2 mg C3N4, and 0.034 mmol CoCl2•6H2O was stirred in a double-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was then added to the mixture, and the mixture was stirred for reduction for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and then dried overnight in a vacuum oven at 60 °C.

[0034] Preparation of 10% Co@MoO3+C3N4: 1.0 mL of an aqueous solution of 1.8 mg MoO3, 16.2 mg C3N4, and 0.034 mmol CoCl2•6H2O was stirred in a double-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was then added to the mixture, and the mixture was stirred for reduction for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and then dried overnight in a vacuum oven at 60 °C.

[0035] MoS2 / MoO 3-x Preparation of / C3N4: 1.0 mL of an aqueous solution of 18.0 mg MoS2 / C3N4 was stirred in a double-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was added to the mixture, and the mixture was reduced at 60°C for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and then dried overnight in a vacuum oven at 60°C.

[0036] 10%Co@MoS2 / MoO 3-x Preparation of / C3N4: 18.0 mg MoS2 / C3N4 and 1.0 mL of an aqueous solution of 0.034 mmol CoCl2•6H2O were stirred in a two-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was added to the mixture, and the mixture was reduced at 60°C for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and dried overnight in a vacuum oven at 60°C. The reaction was then carried out with 10% Co@MoS2 / MoO2. 3-x A similar process to that used for C3N4 synthesized 5% Co@MoS2 / MoO. 3-x / C3N4 and 15% Co@MoS2 / MoO 3-x / C3N4.

[0037] Preparation of 10% Co@MoO3 / C3N4: 18.0 mg MoO3 / C3N4 and 1.0 mL of an aqueous solution of 0.034 mmol CoCl2•6H2O were stirred in a double-necked flask for 5 h. 1.0 mL of an aqueous solution of 0.068 mmol NaBH4 was added to the mixture, and the mixture was stirred for reduction for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and then dried overnight in a vacuum oven at 60 °C.

[0038] Figure 1 The following were shown: C3N4, MoS2, MoS2 / C3N4, and 10% Co@MoS2 / MoO. 3-x X-ray diffraction (XRD) patterns of / C3N4 were obtained to study its crystal structure. The 13.0° and 27.4° crystal planes in C3N4 are (001) and (002) crystal planes, respectively. The peaks of MoS2 at 33° and 58° are (100) and (110) hexagonal phase crystal planes. In MoS2 / C3N4, although the diffraction peaks are weakened, the crystal planes of MoS2 and CN are also observed. With the formation of Z-type heterojunction MoS2 / C3N4, the (002) crystal plane of C3N4 shifts to 28.0°. Compared with the original MoS2 / C3N4, 10% Co@MoS2 / MoO 3-x / C3N4 in MoS2 / MoO 3-x No new peaks appeared after the formation of the interface heterostructure and the loading of Co NPs, indicating that the Co NPs were well dispersed.

[0039] Figure 2 The study utilizes transmission electron microscopy (TEM), EDS spectroscopy, and high-resolution TEM (HRTEM) to investigate Z-type heterojunctions MoS2 / C3N4 and 10% Co@MoS2 / MoO. 3-x The characteristics of / C3N4. From the TEM, EDS, and HRTEM images of MoS2 / C3N4, it is clear that MoS2 / C3N4 inherits the plate-like structure of C3N4 (…). Figure 2 a) In HRTEM, hexagonal MoS2 (002) and (102) lattice fringes can be found. Figure 2 b) and the surface of C3N4 is well covered by MoS2. Figure 2 c). In 10% Co@MoS2 / MoO 3-x In the TEM of / C3N4, Co NPs are well dispersed ( Figure 2 d), and typical (111) lattice fringes of Co NPs were also observed in the HRTEM images. Furthermore, (002) and (103) lattice fringes of MoS2 and (041), (101), and (131) lattice fringes of MoO3 were also found in the magnified HRTEM images. Figure 2 e), which verifies MoS2 and MoO 3-x The formation of heterogeneous interfacial structures.

[0040] Figure 3 10% Co@MoS2 / MoO was measured using X-ray photoelectron spectroscopy (XPS). 3-x The elemental binding energies and chemical states in / C3N4. Figure 3a shows the binding energies and chemical states of 10% Co@MoS2 / MoO. 3-x XPS spectra of / C3N4 indicate the presence of C, N, Mo, S, O, and Co elements. Figure 3 The bg values ​​show C 1s, N 1s, Mo 3d, S 2p, O 1s, and Co 2p. Figure 3 The C 1s in b has two peaks at 284.8 and 288.1 eV, corresponding to the C-C bond and NC=N, respectively. Figure 3 The N 1s in c has four peaks at 398.5, 399.5, 400.9, and 404.5 eV, which should correspond to the sp in the triazine ring. 2 Hybridized CN=C, N–(C)3, amino group C–NHx, and graphitized N species. For Figure 3 In the Mo 3d group, two pairs of Mo 3d peaks were clearly detected. 235.1 and 231.9 eV represent Mo 3d. 6+ The values ​​of Mo 3d 3 / 2 and Mo 3d 5 / 2, and 231.4 eV and 228.1 eV, should be attributed to Mo. 4+ Mo 3d 3 / 2 and Mo3d 5 / 2. MoS2 / MoO 3-x / C3N4 Medium Mo 6+ and Mo 4+ The existence of this is attributed to partial lattice rearrangement during the high-temperature reduction process. Figure 3 The 225.2 eV in d represents S 2s. S 2p shows two strong peaks at 161.6 and 162.8 eV (Figure 3e), corresponding to 10% Co@MoS2 / MoO2. 3-x S 2p 3 / 2 and S 2p 1 / 2 in / C3N4. 10% Co@MoS2 / MoO 3-x The S 2p 3 / 2 and S 2p 1 / 2 ions in / C3N4 shift to lower binding energies, indicating that with the change in MoS2 / MoO 3-x Hybrids are formed, and the chemical microenvironment of the S atom changes. Simultaneously, Figure 3 The 168.3 eV in e indicates the presence of S. 6+ This should be attributed to the conversion of MoS2 to MoS2 / MoO.3-x S during the process 2- Oxidation. O 1s exhibits three peaks near 530.7, 531.1, and 532.1 eV. Figure 3 f), this should correspond to O. 2- Co 2p ( , C=O and H2O adsorbed on the surface. Figure 3 g) Peaks are observed near 781.7 and 797.3 eV, which is Co 2+ The Co 2p 3 / 2 and Co 2p 1 / 2, and 778.8 and 794.4 eV are the Co 2p 3 / 2 and Co 2p 1 / 2 of the cobalt nanoparticles.

[0041] Figure 4 In the study, all samples exhibited photoresponse characteristics, with a photocurrent response of C3N4 < MoS2 / C3N4 < 10% Co@MoS2 / MoO. 3-x / C3N4. MoS2 / C3N4 and 10% Co@MoS2 / MoO 3-x The increased photocurrent density of / C3N4 indicates the formation of a Z-type heterojunction MoS2 / C3N4 and the enrichment of S-vacancy MoS2 / MoO. 3-x The formation of hybrids and the loading of Co NPs accelerate charge separation and transfer. For Figure 4 EIS in b, 10% Co@MoS2 / MoO 3-x The semicircular arc diameter of / C3N4 is smaller than that of MoS2 / C3N4 and C3N4, indicating that 10% Co@MoS2 / MoO 3-x Photogenerated electrons in the C3N4 heterojunction encounter lower resistance. Photoluminescence (PL) spectroscopy was used to evaluate the separation and recombination of photogenerated electron-hole pairs. Due to photoinduced carrier recombination, the PL spectrum of C3N4 exhibits a plateau emission peak near 460 nm (Fig. 4c). The decrease in PL intensity in the heterojunction MoS2 / C3N4 indicates that charge recombination is suppressed, which will favor redox processes due to more efficient interfacial charge transfer. 10% Co@MoS2 / MoO 3-x The spectrum of / C3N4 shows a further decrease in PL intensity, which can be explained by the 10% Co@MoS2 / MoO 3-x The Z-shaped heterostructure and Co NPs present in the / C3N4 composite material inhibit carrier recombination.

[0042]

[0043] Implementation Plan 2: (Table 1, Item 1)

[0044] A 10% Co@C3N4 catalyst (10.0 mg) was added to a two-necked flask. An aqueous solution of NH3BH3 (AB, 1.0 mmol) (1.0 mL) was added to the flask, and the catalytic reaction was immediately initiated at 298 K. The amount of gas generated during the catalytic reaction was monitored by water displacement. Hydrogen production was measured by recording the amount of water discharged. A 75-minute timeframe was obtained for the AB hydrolysis catalyzed by 10% Co@C3N4 under light conditions. -1 TOF.

[0045] Implementation Plan 3: (Table 1, Item 2)

[0046] A 10% Co@C3N4 catalyst (10.0 mg) was added to a two-necked flask. An aqueous solution of NH3BH3 (1.0 mmol) (1.0 mL) was then added to the flask, and the catalytic reaction was initiated under light-free conditions. The amount of gas generated was monitored using the water displacement method during the catalytic reaction. Hydrogen production was measured by recording the amount of water discharged. A 40-minute timeframe was obtained for the AB hydrolysis catalyzed by 10% Co@C3N4 under light-free conditions. -1 TOF.

[0047] Implementation Plan 4: (Table 1, Item 3)

[0048] Put 10% Co@MoS2 / MoO 3-x A catalyst of 10.0 mg C3N4 was added to a two-necked flask. An aqueous solution of 1.0 mL of 1.0 mmol NH3BH3 was added to the flask, and the catalytic reaction was immediately initiated at 298 K. During the catalytic reaction, the amount of gas produced was monitored by water displacement. Hydrogen production was measured by recording the amount of water discharged. Under light conditions, the TOF was 130 min. -1 After the previous hydrogen evolution cycle, the cyclic experiment was conducted by continuously injecting 1.0 mmol of an aqueous solution of NH3BH3 (1.0 mL) into the reaction. Under visible light irradiation, the total number of catalytic cycles was 5, with a 5-minute interval between two adjacent cycles. After 5 cycles, the photocatalytic hydrogen evolution activity of ammonia borane remained highly efficient, with TOF values ​​of 130, 130, 128, 128, and 127 after 5 cycles, respectively.

[0049] Implementation Plan 5: (Table 1, Item 4)

[0050] Put 10% Co@MoS2 / MoO 3-xA catalyst of 10.0 mg C3N4 was added to a two-necked flask. An aqueous solution of 1.0 mL of 1.0 mmol NH3BH3 was added to the flask, and the catalytic reaction was initiated under light-free conditions. The amount of gas produced was monitored by water displacement during the reaction. Hydrogen production was measured by recording the amount of water discharged. Under light-free conditions, the time to fire (T0F) was 66 min. -1 .

[0051] Implementation Plan 6: (Table 1, Item 5)

[0052] A 10% Co@MoS2+C3N4 catalyst (10.0 mg) was added to a two-necked flask. An aqueous solution of NH3BH3 (1.0 mmol) (1.0 mL) was added to the flask, and the catalytic reaction was immediately initiated at 298 K. The amount of gas generated during the catalytic reaction was monitored using the water displacement method. Hydrogen production was measured by recording the amount of water discharged. The 42 min time under light conditions during the 10% Co@C3N4 catalytic AB hydrolysis process was obtained. -1 TOF.

[0053] Implementation Plan 7: (Table 1, Item 6)

[0054] Will MoS2 / MoO 3-x A catalyst of 10.0 mg / C3N4 was added to a two-necked flask. An aqueous solution of 1.0 mL of NH3BH3 (1.0 mmol) was added to the flask, and the catalytic reaction was immediately initiated at 298 K. During the catalytic reaction, the amount of gas generated was monitored by water displacement. Hydrogen production was measured by recording the amount of water discharged. In the MoS2 / MoO2 mixture... 3-x The C3N4 catalyst is relatively stable during the hydrolysis of AB, achieving a 0 min result under light conditions. -1 TOF.

[0055] Implementation Plan 8: (Table 1, Item 7)

[0056] A 10% Co@MoO3 / C3N4 catalyst (10.0 mg) was added to a two-necked flask. An aqueous solution of NH3BH3 (1.0 mmol) (1.0 mL) was added to the flask, and the catalytic reaction was immediately initiated at 298 K. The amount of gas generated during the catalytic reaction was monitored using the water displacement method. Hydrogen production was measured by recording the amount of water discharged. A 100-minute timeframe was obtained for the AB hydrolysis catalyzed by 10% Co@C3N4 under light conditions. -1 TOF.

[0057] Implementation Plan 9: (Table 1, Item 8)

[0058] A 10% Co@MoO3 / C3N4 catalyst (10.0 mg) was added to a two-necked flask. An aqueous solution of NH3BH3 (1.0 mmol) (1.0 mL) was then added to the flask, and the catalytic reaction was initiated under light-free conditions. The amount of gas generated was monitored using the water displacement method during the catalytic reaction. Hydrogen production was measured by recording the amount of water discharged. A 27-minute timeframe was achieved for the AB hydrolysis catalyzed by 10% Co@C3N4 under light-free conditions. -1 TOF.

[0059] Implementation Plan 10: (Table 1, Item 9)

[0060] A catalyst of 10.0 mg MoO3 / C3N4 was added to a two-necked flask. An aqueous solution of 1.0 mL of 1.0 mmol NH3BH3 was added to the flask, and the catalytic reaction was immediately initiated at 298 K. The amount of gas produced was monitored by water displacement during the catalytic reaction. Hydrogen production was measured by recording the amount of water discharged. The reaction time was 0 min under light conditions with MoO3 / C3N4. -1 TOF.

[0061] Implementation Plan 11: (Table 1, Item 10)

[0062] A 10% Co@MoO3+C3N4 catalyst (10.0 mg) was added to a two-necked flask. An aqueous solution of NH3BH3 (1.0 mmol) (1.0 mL) was added to the flask, and the catalytic reaction was immediately initiated at 298 K. During the catalytic reaction, the amount of gas generated was monitored using the water displacement method. Hydrogen production was measured by recording the amount of water discharged. A 25-minute timeframe was obtained for the AB hydrolysis catalyzed by 10% Co@MoO3+C3N4 under light conditions. -1 TOF.

[0063] Implementation Plan 12: (Table 1, Item 11)

[0064] Put 5%Co@MoS2 / MoO 3-X A catalyst of 10.0 mg / C3N4 was added to a two-necked flask. An aqueous solution of 1.0 mL of 1.0 mmol NH3BH3 was added to the flask, and the catalytic reaction was immediately initiated at 298 K. The amount of gas produced was monitored by water displacement during the catalytic reaction. Hydrogen production was measured by recording the amount of water discharged. The reaction was carried out in a 5% Co@MoS2 / MoO2 mixture. 3-X During the C3N4-catalyzed AB hydrolysis process, a time of 110 min was obtained under light conditions. -1TOF.

[0065] Implementation Plan 13: (Table 1, Item 12)

[0066] Put 15%Co@MoS2 / MoO 3-X A catalyst of 10.0 mg / C3N4 was added to a two-necked flask. An aqueous solution of 1.0 mL of 1.0 mmol NH3BH3 was added to the flask, and the catalytic reaction was immediately initiated at 298 K. The amount of gas generated during the catalytic reaction was monitored by water displacement. Hydrogen production was measured by recording the amount of water discharged. The reaction was carried out in a 15% Co@MoS2 / MoO2 mixture. 3-X During the C3N4-catalyzed AB hydrolysis process, a time of 115 min was obtained under light conditions. -1 TOF.

Claims

1. A 10% Co@MoS2 / MoO 3-x The application of C3N4 photocatalyst in the photocatalytic hydrolysis of ammonia borane to produce hydrogen is characterized by: Photocatalytic hydrolysis of ammonia borane to produce hydrogen includes the following steps: adding 10% Co@MoS2 / MoO 3-x The C3N4 composite catalyst was added to a double-necked flask, and an aqueous solution of the substrate NH3BH3 was added to the mixture. The catalytic reaction was initiated immediately at 298 K. Different methods for preparing the composite catalysts include the following steps: Preparation of C3N4: 5.0 g of melamine was heated to 500 °C at a rate of 5 °C / min and held for 2 h to synthesize C3N4. The light yellow sample was collected and ground into powder. Preparation of MoS2: First, 0.48 g NaMoO4·2H2O and 0.76 g thiourea were dissolved in 40 mL of deionized water. The mixture was effectively dispersed by magnetic stirring for 30 minutes. The uniform and transparent solution was loaded into a high-pressure autoclave with a 50 mL polytetrafluoroethylene liner and treated at 240 °C for 22 hours. The black precipitate was collected by centrifugation and washed with deionized water and ethanol. Then, it was dried in an oven at 85 °C for 24 hours to obtain a black MoS2 sample. Preparation of MoS2 / C3N4: 0.495 g C3N4 and 0.055 g MoS2 (10 wt%) were dispersed in deionized water to form a mixture. The resulting solution was then vigorously stirred for 1 hour, followed by ultrasonic dispersion for 2 hours to obtain a homogeneous mixture. This mixture was dried at 80°C for 12 hours to remove the solvent. The resulting product was then subjected to 15 mL / min... -1 The heterojunction interface was further consolidated by calcination at 300°C for 2 hours under a nitrogen flow to finally obtain a MoS2 / C3N4 heterojunction composite material with a MoS2 mass ratio of 10wt%. 10% Co@MoS2 / MoO 3-x Preparation of / C3N4: 18.0 mg MoS2 / C3N4 and 1.0 mL of 0.034 mmol CoCl2·6H2O aqueous solution were stirred in a double-necked flask for 5 h. 1.0 mL of 0.068 mmol NaBH4 aqueous solution was added to the mixture. The mixture was reduced at 60 °C for 2 h. After the reaction was complete, the mixture was washed several times with deionized water and ethanol, and dried overnight in a vacuum oven at 60 °C.

2. The 10% Co@MoS2 / MoO as described in claim 1 3-x The application of C3N4 photocatalyst in the photocatalytic hydrolysis of ammonia borane to produce hydrogen is characterized by: The photocatalytic hydrolysis system for hydrogen production from ammonia borane is simple and easy to operate. It can be used for efficient hydrogen production from ammonia borane under mild reaction conditions, and the time-to-flight (TOF) can reach 130.0 min under optimized conditions. -1 .

3. A 10% Co@MoS2 / MoO2 mixture as described in claim 1 3-x The application of C3N4 photocatalyst in the photocatalytic hydrolysis of ammonia borane to produce hydrogen is characterized by: The catalyst exhibits good recyclability; after five cycles, the photocatalyst still maintains high photocatalytic hydrogen production activity.

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