Preparation and Application of RuCoMoOx Catalyst with Controlled Crystal / Amorphous Component Ratio by Microwave Method

Abstract

The present invention is applied to the field of new energy materials and electrocatalytic water splitting technology. A Ru-doped crystalline / amorphous CoMoOx nanosheet catalyst grown on nickel foam (NF) by a coprecipitation-microwave method is adopted, denoted as a / c-RuCoMoOx / NF. And by adjusting the microwave time, the ratio of the crystalline / amorphous components is controlled, and thus a / c-RuCoMoOx / NF with the best crystalline / amorphous component ratio and rich crystalline / amorphous heterointerfaces is obtained. When this catalyst is used as the working electrode, it exhibits excellent HER and OER activities and stabilities in an electrolyte of 1.0 M KOH. In addition, it also has excellent overall water splitting activity and stability in an electrolytic cell with an electrolyte of 1.0 M KOH. According to the Faraday test, the Faraday efficiency is close to 100%.

Description

Technical Field:

[0001] The present invention belongs to the technical field of new energy materials and electrocatalytic water splitting, and specifically relates to an a / c-RuCoMoOx / NF catalyst; it also relates to a preparation method of the catalyst and its electrocatalytic performances for HER, OER and overall water splitting in 1.0 M KOH electrolyte. Background Art:

[0002] The development and utilization of clean energy have become the main theme of this era. As a new type of clean energy, hydrogen has the characteristics of zero carbon emission and high energy storage, and can replace fossil fuels in industrial production. Among all hydrogen production technologies, water electrolysis technology stands out due to its zero carbon emission and mature development. Electrocatalysts are an important factor affecting the efficiency of water electrolysis reactions. Currently, most electrocatalysts used in industry are noble metal-based electrocatalysts. In particular, Pt / C and RuO2 (or IrO2) have become important indicators for evaluating the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) respectively due to their excellent performances. However, their high costs and limited crustal storage have restricted their widespread applications. Based on this, non-noble metal-based catalysts are considered good substitutes for noble metal-based catalysts. Among them, sulfides, phosphides and oxides are considered promising bifunctional catalysts for overall water splitting. Although non-noble metal-based composites can also provide accelerated kinetics, there are still obvious gaps between them. Therefore, doping trace amounts of noble metals into non-noble metal-based catalysts is a clever method to reduce costs and improve intrinsic activity. Qu and his colleagues demonstrated that the doping of Ru in NiFe-P catalysts effectively enriched the active sites, resulting in the optimal Gibbs free energy (Appl. Catal., B, 2020, 263, 118324). Liang et al. found that the doping of Ir increased the electron density around the Ti4 sites, thus promoting oxygen adsorption and improving the OER activity (Angew. Chem., Int. Ed., 2019, 58, 7631-7635). Yang and his colleagues found that the introduction of Ru atoms into Cu nanocrystals adjusted the electronic structure, making the hydrogen adsorption energy close to zero (Sci. Bull., 2021, 66, 257-264).

[0003] Heterointerface engineering strategies with unique electronic and synergistic effects have considerable application potential in enriching catalytic functions and improving intrinsic activity. In particular, electrocatalysts with amorphous / crystalline (a / c) heterostructures often exhibit remarkable activity due to the large structural differences. Specifically, the amorphous phase in the a / c heterostructure has good structural flexibility due to the disordered arrangement of internal atoms, which is conducive to the reconstruction of the electrocatalyst surface and the improvement of corrosion resistance during the catalytic process. At the same time, a large number of unsaturated coordination bonds stimulate active sites, improving the electrocatalytic activity. Hu et al. prepared ruthenium atom-loaded FeCoNi LDH materials by a self-template cation exchange method, which have abundant amorphous / crystalline interfaces (Adv. Energy Mater., 2021, 11, 2002816). Zhang et al. found that the heterointerface between x x and amorphous Ru / Rh-FeOOH accelerates the charge transfer of FeOOH and improves the conductivity of FeOOH, thus endowing the catalyst with good catalytic activity (Small, 2022, 18, 2200173). At the same time, Quan et al. used PH3 generated during the controllable phosphidation process to force some lattice O to be replaced by P atoms, thereby synthesizing ruthenium-doped CoMoP (Ru-CMP) nanoparticles on the surface of ruthenium-doped CoMoO4 (Ru-CMO) domains, forming a catalyst (Ru-CMOP) with abundant phase interfaces and multiphase interfaces. The synergistic effect of the two enables the catalyst to exhibit excellent water splitting performance, with a current density reaching 100 mA cm at a low voltage of 1.697 V. -2 (Nano Energy, 2022, 101, 107566). Generally speaking, the construction of the a / c heterostructure optimizes the intrinsic activity of electrocatalysts. However, the controllable regulation of the a / c heterointerface region and its internal relationship with electrocatalytic performance lack systematic research. In addition, considering the cost, economic benefits, and utilization efficiency of noble metals, it is necessary to develop a rapid and simple method to obtain highly active electrocatalysts with various crystalline / amorphous heterointerfaces.

[0004] Considering these, we prepared an a / c-RuCoMoOx / NF electrocatalyst with a controllable amorphous / crystalline heterointerface by a simple co-precipitation-microwave treatment method. Surprisingly, the microwave time directly affects the proportion of the amorphous / crystalline region under the action of a high-frequency magnetic field, thus affecting the electron transport ability and the background electrocatalytic activity. As expected, the a / c-RuCoMoOx / NF electrocatalyst has excellent OER and OER performance. In addition, the electrolytic cell assembled with the a / c-RuCoMoOx / NF material can drive 100 mA cm with only 1.54 V. -2Current density. This study provides a new idea for optimizing the electrocatalytic performance by controlling the microwave time to regulate the crystalline / amorphous heterointerfaces. SUMMARY OF THE INVENTION:

[0005] Aiming at the deficiencies of the prior art and the needs of research and application in this field, one of the purposes of the present invention is to provide an a / c-RuCoMoOx / NF electrocatalyst, and an a / c-RuCoMoOx / NF catalyst with rich crystalline / amorphous heterointerfaces is prepared by a co-precipitation - microwave method.

[0006] Another purpose of the present invention is to provide an electrocatalytic water splitting catalyst with high activity and stability. The specific steps are as follows:

[0007] (a) Preparation of a / c-RuCoMoOx / NF

[0008] First, nickel foam (2 cm * 3 cm) is ultrasonically treated in acetone, 1 M HCl, ethanol and other solutions for 10 min each, and then the nickel foam is dried for later use; 0.821 g of 2-methylimidazole (2-MIM) is dissolved in 20 mL of ultrapure water, and then quickly injected into 20 mL of cobalt nitrate solution (0.125 mol / L), and ultrasonically treated for 5 min to make the solution mix evenly. The pre-treated NF is immersed in the mixed solution for 4 h. Finally, the Co-ZIF-L nanosheet array (Co-ZIF-L / NF) grown on NF is rinsed with ultrapure water and ethanol, and dried overnight in an electric blast drying oven at 60 °C for later use; 10 mg of RuCl3 and 10 mg of H 12 Mo 12 N3O 40 P·xH2O is dissolved in 5 mL of ultrapure water and mixed evenly. Then, the pre-prepared Co-ZIF-L / NF (2 cm * 3 cm) is immersed in the solution. Finally, the quartz bottle containing the sample is placed in a microwave oven and reacted for 60 - 180 s. The specific steps of the optimal experimental scheme are as follows: First, nickel foam (2 cm * 3 cm) is ultrasonically treated in acetone, 1 M HCl, ethanol and other solutions for 10 min each, and then the nickel foam is dried for later use; 0.821 g of 2-methylimidazole (2-MIM) is dissolved in 20 mL of ultrapure water, and then quickly injected into 20 mL of cobalt nitrate solution (0.125 mol / L), and ultrasonically treated for 5 min to make the solution mix evenly. The pre-treated NF is immersed in the mixed solution for 4 h. Finally, the Co-ZIF-L nanosheet array (Co-ZIF-L / NF) grown on NF is rinsed with ultrapure water and ethanol, and dried overnight in an electric blast drying oven at 60 °C for later use; 10 mg of RuCl3 and 10 mg of H 12 Mo 12 N3O 40P·xH2O was dissolved in 5 mL of ultrapure water and mixed evenly. Then, the pre-prepared Co-ZIF-L / NF (2 cm * 3 cm) was immersed in the solution. Finally, the quartz bottle containing the sample was placed in a microwave oven and reacted for 140 s. The reaction product was denoted as a / c-RuCoMoOx / NF, and this catalyst had a nanosheet structure with an average thickness of 100 nm.

[0009] (b) Test results

[0010] The test was carried out in the voltage range of 0.07 V vs. RHE to 0.53 V vs. RHE. The data showed that in 1.0 M KOH electrolyte, a current density of 100 mA cm -2 could be obtained at low overpotentials of 0.128 V vs. RHE (HER) and 0.337 V vs. RHE (OER). At the same time, it had good stability. After 30 hours of stability test, the HER and OER activities did not decrease significantly. The experiment also proved that in a 1.0 M KOH alkaline electrolytic cell, a current density of 100 mA cm -2 could be obtained at a voltage of 1.54 V. After 4000 cycles of cv test and 30 hours of stability test, the activity did not decrease significantly, and the Faraday efficiency was close to 100%.

[0011] Among them, in step (a), this catalyst had a nanosheet structure with an average thickness of 100 nm. The treatment time of nickel foam in solutions such as acetone, 1 M HCl, and ethanol was 10 min each. A solution of 0.821 g of 2-methylimidazole (2-MIM) dissolved in 20 mL of ultrapure water was quickly injected into 20 mL of cobalt nitrate solution (0.125 mol / L). The ultrasonic mixing time was 5 min. The room temperature soaking time was 4 h. The microwave reaction time range was 60 - 180 s. In step (b), the test voltage range of this material was 0.07 V vs. RHE to 0.53 V vs. RHE. In 1.0 M KOH electrolyte, a current density of 100 mA cm -2 could be obtained at low overpotentials of 0.128 V vs. RHE (HER) and 0.337 V vs. RHE (OER). After 30 hours of stability test, the HER and OER activities did not decrease significantly, showing excellent stability. In a 1.0 M KOH alkaline electrolytic cell, a current density of 100 mA cm -2 could be obtained at a voltage of 1.54 V. After 4000 cycles of cv test and 32 hours of stability test, the activity did not decrease significantly, and the Faraday efficiency was close to 100%.

[0012] The co-precipitation - microwave method adopted by the present invention successfully prepares a / c-RuCoMoOx / NF. The a / c-RuCoMoOx / NF catalyst with rich amorphous / crystalline heterointerfaces has excellent electrocatalytic water splitting activity and stability in 1.0 M KOH.

[0013] Compared with the reported technologies, the present invention has the following advantages:

[0014] 1) The a / c-RuCoMoOx / NF material described in the present invention has a simple and rapid preparation process and can be prepared in large quantities;

[0015] 2) The electrocatalyst material described in the present invention has a rich amorphous / crystalline heterostructure. The strong electronic interaction it possesses promotes charge transfer and enhances electrocatalytic activity;

[0016] 3) The catalytic material described in the present invention has excellent HER and OER activities and stabilities. In 1.0 M KOH electrolyte, the catalytic material can obtain a current density of 100 mA cm -2 at a low overpotential of 0.128 V vs. RHE (HER) and 0.337 V vs. RHE (OER). After 30 hours of stability testing, the HER and OER activities do not decrease significantly, showing good HER and OER stabilities. Moreover, the morphology after the reaction remains good, indicating excellent structural stability;

[0017] 4) The catalyst described in the present invention can obtain a current density of 100 mA cm -2 at a voltage of 1.54 V in a 1.0 M KOH alkaline electrolytic cell. After 4000 cycles of CV testing and 32 hours of stability testing, the activity does not decrease significantly, and the Faraday efficiency is close to 100%. Description of the drawings:

[0018] Figure 1 Scanning electron microscopy image (a), transmission electron microscopy image (b), X-ray diffraction pattern (c) and high-resolution transmission image (d) of a / c-RuCoMoOx / NF obtained in Example 3.

[0019] Figure 2 Scanning electron microscopy images of the catalyst materials prepared in Examples 1, 2, and 4.

[0020] Figure 3 High-resolution transmission electron microscopy images of the catalyst materials prepared in Examples 1, 2, and 4.

[0021] Figure 4HER linear sweep voltammetry curves (a), Tafel slopes (b), and impedance plots (c) of the catalyst materials prepared in Examples 1, 2, 3, and 4 in 1.0 M KOH electrolyte.

[0022] Figure 5 OER linear sweep voltammetry curves (a), Tafel slopes (b), and impedance plots (c) of the catalyst materials prepared in Examples 1, 2, 3, and 4 in 1.0 M KOH electrolyte.

[0023] Figure 6 Chronoamperometry tests of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 for HER and OER in 1.0 M KOH electrolyte.

[0024] Figure 7 Overall water splitting tests of the catalyst materials prepared in Examples 1, 2, 3, and 4 in 1.0 M KOH electrolyte.

[0025] Figure 8 4000-cycle cyclic voltammetry tests (a) and chronoamperometry tests (b) of overall water splitting of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 in 1.0 M KOH electrolyte. [[ID=I7]]

[0026] Figure 9 Faraday tests process (a) and Faraday test results (b) of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3.

[0027] Figure 10 Scanning electron microscopy images of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 after HER test.

[0028] Figure 11 Scanning electron microscopy images of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 after OER test. Detailed implementation method:

[0029] To make the objectives, technical methods, and highlights of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be clear that the specific examples described are only used to explain the present invention, but not to limit the present invention.

[0030] Example 1:

[0031] First step, first, ultrasonically clean the nickel foam (2 cm * 3 cm) in acetone, 1 M HCl, ethanol and other solutions for 10 min each, and then dry the nickel foam for later use;

[0032] Step 2: Dissolve 0.821 g of 2-methylimidazole (2-MIM) in 20 mL of ultrapure water, and then quickly inject it into 20 mL of cobalt nitrate solution (0.125 mol / L). Ultrasonicate for 5 min to mix the solution evenly. Immerse the pre-treated NF in the mixed solution for 4 h. Finally, rinse the Co-ZIF-L nanosheet array (Co-ZIF-L / NF) grown on the NF with ultrapure water and ethanol, and dry it overnight in an electric blast oven at 60 °C for standby;

[0033] Step 3: Preparation of the a / c-RuCoMoOx / NF-60s material. Dissolve 10 mg of RuCl3 and 10 mg of H 12 Mo 12 N3O 40 P·xH2O in 5 mL of ultrapure water and mix evenly. Then, immerse the pre-prepared Co-ZIF-L / NF (2 cm * 3 cm) into the solution. Finally, place the quartz bottle containing the sample in a microwave oven and react for 60 s.

[0034] Example 2:

[0035] Step 1: First, ultrasonicate the nickel foam (2 cm * 3 cm) in acetone, 1 M HCl, ethanol and other solutions for 10 min each, and dry the nickel foam for standby;

[0036] Step 2: Dissolve 0.821 g of 2-methylimidazole (2-MIM) in 20 mL of ultrapure water, and then quickly inject it into 20 mL of cobalt nitrate solution (0.125 mol / L). Ultrasonicate for 5 min to mix the solution evenly. Immerse the pre-treated NF in the mixed solution for 4 h. Finally, rinse the Co-ZIF-L nanosheet array (Co-ZIF-L / NF) grown on the NF with ultrapure water and ethanol, and dry it overnight in an electric blast oven at 60 °C for standby;

[0037] Step 3: Preparation of the a / c-RuCoMoOx / NF-1ns material. Dissolve 10 mg of RuCl3 and 10 mg of H 12 Mo 12 N3O 40 P·xH2O in 5 mL of ultrapure water and mix evenly. Then, immerse the pre-prepared Co-ZIF-L / NF (2 cm * 3 cm) into the solution. Finally, place the quartz bottle containing the sample in a microwave oven and react for 100 s.

[0038] Example 3:

[0039] Step 1: First, ultrasonicate the nickel foam (2 cm * 3 cm) in acetone, 1 M HCl, ethanol and other solutions for 10 min each, and dry the nickel foam for standby;

[0040] In the second step, 0.821 g of 2-methylimidazole (2-MIM) was dissolved in 20 mL of ultrapure water, and then quickly injected into 20 mL of cobalt nitrate solution (0.125 mol / L). The solution was sonicated for 5 min to mix evenly. The pre-treated NF was immersed in the mixed solution for 4 h. Finally, the Co-ZIF-L nanosheet array (Co-ZIF-L / NF) grown on NF was rinsed with ultrapure water and ethanol, and dried overnight in an electric blast drying oven at 60 °C for standby;

[0041] In the third step, for the preparation of the a / c-RuCoMoOx / NF material, 10 mg of RuCl3 and 10 mg of H 12 Mo 12 N3O 40 P·xH2O were dissolved in 5 mL of ultrapure water and mixed evenly. Then, the pre-prepared Co-ZIF-L / NF (2 cm * 3 cm) was immersed in the solution. Finally, the quartz bottle containing the sample was placed in a microwave oven and reacted for 140 s.

[0042] Example 4:

[0043] In the first step, first, the nickel foam (2 cm * 3 cm) was sonicated in acetone, 1 M HCl, ethanol and other solutions for 10 min each, and the nickel foam was dried for standby;

[0044] In the second step, 0.821 g of 2-methylimidazole (2-MIM) was dissolved in 20 mL of ultrapure water, and then quickly injected into 20 mL of cobalt nitrate solution (0.125 mol / L). The solution was sonicated for 5 min to mix evenly. The pre-treated NF was immersed in the mixed solution for 4 h. Finally, the Co-ZIF-L nanosheet array (Co-ZIF-L / NF) grown on NF was rinsed with ultrapure water and ethanol, and dried overnight in an electric blast drying oven at 60 °C for standby;

[0045] In the third step, for the preparation of the a / c-RuCoMoOx / NF-180s material, 10 mg of RuCl3 and 10 mg of H 12 Mo 12 N3O 40 P·xH2O were dissolved in 5 mL of ultrapure water and mixed evenly. Then, the pre-prepared Co-ZIF-L / NF (2 cm * 3 cm) was immersed in the solution. Finally, the quartz bottle containing the sample was placed in a microwave oven and reacted for 180 s.

[0046] The catalysts prepared in Examples 1-4 were tested in the voltage range of 0.07 V vs. RHE to 0.53 V vs. RHE. As Figure 4 and Figure 5The results show that the electrocatalyst prepared in Example 3 exhibits excellent HER and OER electrocatalytic performance. In 1.0 M KOH electrolyte, a current density of 100 mA cm -2 can be obtained at low overpotentials of 0.128 V vs. RHE (HER) and 0.337 V vs. RHE (OER). Meanwhile, it has good stability. After 30 hours of stability testing, the HER and OER activities do not decrease significantly ( Figure 6 ). The experiment also proves that in a 1.0 M KOH alkaline electrolyzer, a current density of 100 mA cm -2 can be obtained at a voltage of 1.54 V ( Figure 7 ). Meanwhile, after 32 hours of stable 4000-cycle CV testing and 30 hours of stability testing, the activity does not decrease significantly ( Figure 8 ), and the Faraday efficiency is close to 100% ( Figure 9 ).

[0047] Figure 1 Figures (a), (b), (c) and (d) are the scanning electron microscopy image, transmission electron microscopy image, X-ray diffraction pattern and high-resolution transmission image of a / c-RuCoMoOx / NF obtained in Example 3. As can be seen from Figure (a), the catalyst material prepared in Example 3 has a nanosheet structure with an average thickness of 100 nm. Further from Figure (b), it can be known that the prepared catalyst presents a nanosheet morphology. From Figure (c), it can be seen that the synthesized catalyst material has two phases of CoMoO4 and CoO. From Figure (d), it can be known that the catalyst has a rich amorphous / crystalline heterointerface.

[0048] Figure 2 Figures are the scanning electron microscopy images of the catalyst materials prepared in Examples 1, 2 and 4.

[0049] Figure 3 Figures are the high-resolution transmission electron microscopy images of the catalyst materials prepared in Examples 1, 2 and 4. The catalyst materials prepared in Examples 1, 2 and 4 all have amorphous / crystalline heterointerfaces. However, the area ratio of amorphous / crystalline of the catalyst materials with different microwave times is different. As the microwave time increases, the amorphous RuCoMoOx region increases.

[0050] Figure 4HER linear sweep voltammetry curves (a), Tafel slopes (b), and impedance plots (c) of the catalyst materials prepared in Examples 1, 2, 3, and 4 in 1.0 M KOH electrolyte. As can be seen from (a), the a / c-RuCoMoOx / NF catalyst material obtained in Example 3 has the most excellent HER activity. It can be known from (b) that the a / c-RuCoMoOx / NF catalyst material obtained in Example 3 has the fastest reaction kinetics. In (c), the a / c-RuCoMoOx / NF catalyst material obtained in Example 3 has the fastest charge transfer rate.

[0051] Figure 5 OER linear sweep voltammetry curves (a), Tafel slopes (b), and impedance plots (c) of the catalyst materials prepared in Examples 1, 2, 3, and 4 in 1.0 M KOH electrolyte. As can be seen from (a), the a / c-RuCoMoOx / NF catalyst material obtained in Example 3 has the most excellent OER activity. It can be known from (b) that the a / c-RuCoMoOx / NF catalyst material obtained in Example 3 has the fastest reaction kinetics. In (c), the a / c-RuCoMoOx / NF catalyst material obtained in Example 3 has the fastest charge transfer rate.

[0052] Figure 6 Chronocurrent tests of HER and OER of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 in 1.0 M KOH electrolyte. It is proved that the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 has excellent HER and OER electrocatalytic stability in 1.0 M KOH electrolyte.

[0053] Figure 7 Overall water splitting tests of the catalyst materials prepared in Examples 1, 2, 3, and 4 in 1.0 M KOH electrolyte.

[0054] Figure 8 4000-cycle cyclic voltammetry tests (a) and chronocurrent tests (b) of overall water splitting of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 in 1.0 M KOH electrolyte. It is proved that the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 has excellent overall water splitting electrocatalytic stability in 1.0 M KOH electrolyte.

[0055] Figure 9 Faraday tests process (a) and Faraday test results (b) of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3. It can be known from (a) and (b) that the Faraday efficiency of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 is close to 100%.

[0056] Figure 10 Scanning electron microscopy image of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 after HER testing. It can be seen that the a / c-RuCoMoOx / NF catalyst material does not have a nanosheet morphology after the HER reaction.

[0057] Figure 11 Scanning electron microscopy image of the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 after OER testing. It can be seen that the a / c-RuCoMoOx / NF catalyst material does not have a nanosheet morphology after the OER reaction.

[0058] From Figure 10 and Figure 11 it can be seen that the a / c-RuCoMoOx / NF catalyst material prepared in Example 3 has good structural stability.

Claims

1. A Ru-doped crystalline / amorphous CoMoOx nanosheet catalyst, denoted as a / c-RuCoMoOx / NF, was prepared on nickel foam by a coprecipitation-microwave method and applied to the electrocatalytic water splitting reaction, characterized in that, The microwave time can regulate the proportion of crystalline / amorphous components; The preparation method of the a / c-RuCoMoOx / NF is as follows: First, ultrasonically clean a 2 cm * 3 cm nickel foam in acetone, 1 M HCl, and ethanol solution for 10 min each, then dry the nickel foam for later use. Dissolve 0.821 g of 2-methylimidazole in 20 mL of ultrapure water, and then quickly inject it into 20 mL of a cobalt nitrate solution with a concentration of 0.125 mol / L. Ultrasonically mix the solution for 5 min, and soak the pre-treated NF in the mixed solution for 4 h. Finally, rinse the Co-ZIF-L nanosheet arrays grown on the NF with ultrapure water and ethanol, and dry them overnight in a 60 °C electric blast drying oven for later use. Dissolve 10 mg of RuCl3 and 10 mg of H 12 Mo 12 N3O 40 P·xH2O in 5 mL of ultrapure water and mix evenly. Then, immerse the pre-prepared 2 cm * 3 cm Co-ZIF-L nanosheet arrays into the solution. Finally, place the quartz bottle containing the sample into a microwave oven and react for 140 s. The reaction product is denoted as a / c-RuCoMoOx / NF, and this catalyst has a nanosheet structure with an average thickness of 100 nm.

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