A P-MoO 2 / P-Fe 3 O 4 Preparation method of heterostructured nanoribbons and their electrocatalytic application

Abstract

The invention relates to a preparation method of a P-MoO2 / P-Fe3O4 heterogeneous structure nanobelt and its electrocatalytic application. Specifically, α-MoO3 powder is dissolved in H2O2 solution, and the α-MoO3 nanobelt is obtained by a hydrothermal synthesis method; then the mixture of the α-MoO3 nanobelt and Fe(NO3)3·9H2O is evenly ground and then put into a porcelain boat; NaH2PO2·H2O is put into another porcelain boat, and the two porcelain boats are put into a tubular furnace, wherein the porcelain boat filled with NaH2PO2·H2O is placed upstream, and heated in an Ar atmosphere to obtain the P-MoO2 / P-Fe3O4 heterogeneous structure nanobelt; and the P-MoO2 / P-Fe3O4 heterogeneous structure nanobelt is used in electrocatalytic water oxidation reaction and electrocatalytic water decomposition reaction.

Description

Technical Field

[0001] The invention relates to a preparation method of a P-MoO2 / P-Fe3O4 heterostructure nanobelt and its electrocatalytic application, belonging to the field of material preparation and application. Background Art

[0002] Mo-based oxides include MoO3, MoO2, etc., which are inexpensive and easy to prepare, and have aroused great research interest. 2 , with a certain conductivity. Electrocatalytic water decomposition is an important way to prepare hydrogen in a green way. MoO2 has a weak ability to electrocatalyze water decomposition, so regulating the surface structure of MoO2 to achieve efficient catalytic water decomposition has important theoretical and practical significance.

[0003] Methods such as heteroatom doping, building heterostructures, and forming defect sites can effectively regulate the electronic structure of materials and expose more active sites. For example, Lyu et al. synthesized CoO-MoO2 nanocages using ZIF-67 and Na2MoO4, and achieved the catalytic decomposition of oxygen from water at low voltage. When the voltage was 312mV, the electrocatalytic water oxidation was 10mA / cm 2 (Advanced Functional Materials, 2017; 27(34): 1702324). Wang et al. synthesized (P,W)-MoO2 / NF using (NH4)6Mo7O2·4H2O, Na2WO4·2H2O and NaH2PO2, and achieved good water electrolysis activity at low voltage. When the voltage was 308mV, the electrocatalytic water oxidation was 40mA / cm 2 (Applied Surface Science, 2020; 529: 146987). Zhou et al. constructed a Ni-MoO2@SCG composite material, which has high activity in catalyzing water reactions at room temperature. When the voltage is 278mV, the electrocatalytic water oxidation is 10mA / cm 2 (Journal of Electroanalytical Chemistry, 2021; 897:115555). In summary, there are few studies on the morphology-controlled modulation of MoO2 to achieve efficient electrocatalytic water oxidation and electrocatalytic water decomposition.

[0004] Studies have shown that electrolysis of water can efficiently produce hydrogen, which is a challenge to achieve green energy and solve environmental problems. Therefore, P doping, increasing vacancies, and constructing P-MoO2 / P-Fe3O4 heterogeneous interface structures are of great practical significance for regulating MoO2 to prepare highly active and stable electrolytic water decomposition catalysts. Summary of the invention

[0005] The present invention aims to provide a preparation method of a P-MoO2 / P-Fe3O4 heterostructure nanobelt and its electrocatalytic application.

[0006] Based on the above purpose, the technical solutions involved in the present invention are as follows:

[0007] (1) A method for preparing P-MoO2 / P-Fe3O4 heterostructure nanobelts: α-MoO3 powder is dissolved in H2O2 solution, reacted at 140-200°C for 2-24 hours by a hydrothermal synthesis method, the reaction product is centrifuged and dried to obtain α-MoO3 nanobelts; then a mixture of α-MoO3 nanobelts and Fe(NO3)3·9H2O is ground evenly and then placed in a porcelain boat; NaH2PO2·H2O is placed in another porcelain boat, the two porcelain boats are placed in a tubular furnace, the porcelain boat containing NaH2PO2·H2O is placed upstream, and heated in an Ar atmosphere to obtain P-MoO2 / P-Fe3O4 heterostructure nanobelts.

[0008] In the above preparation method, the mass of the α-MoO3 powder is 0.5-2g, and the volume of the H2O2 solution is 5-20mL.

[0009] In the above preparation method, the width of the α-MoO3 nanobelt is 90-300nm and the length is 400-6000nm.

[0010] In the above preparation method, the mass of the α-MoO3 nanobelt is 20-40 mg, the mass of Fe(NO3)3·9H2O is 20-40 g, and the mass of NaH2PO2·H2O is 0.5-2 g.

[0011] The above-mentioned preparation method comprises the following steps: grinding the mixture of α-MoO3 nanobelts and Fe(NO3)3·9H2O evenly and then putting it into a porcelain boat; taking NaH2PO2·H2O and putting it into another porcelain boat; putting the two porcelain boats into a tubular furnace, wherein the porcelain boat containing NaH2PO2·H2O is placed upstream, and heating in a 10-30mL / min Ar atmosphere at a heating temperature of 200-400°C for a heating time of 1-5 hours.

[0012] In the above-mentioned preparation method, the width of the P-MoO2 / P-Fe3O4 heterostructure nanobelt is 120-300nm, the length is 350-7000nm, and the molar ratio of P / Mo / Fe is (1-2):(10-13):(0.05-2).

[0013] In the above-mentioned preparation method, P-MoO2 / P-Fe3O4 heterostructure nanobelts are doped with P-MoO2 and P-doped with Fe3O4 to form a heterostructure, the MoO2 crystal phase belongs to the standard card JCPDS#32-0671, and the Fe3O4 crystal phase belongs to the standard card JCPDS#19-0629.

[0014] (2) Application of the P-MoO2 / P-Fe3O4 heterostructure nanobelts prepared by the above preparation method in electrocatalytic water oxidation reaction and electrocatalytic water decomposition reaction; electrocatalytic water oxidation reaction, the current density is 10mA / cm at a voltage of 1.48-1.5V 2 ; Electrocatalytic water splitting reaction, current density 10mA / cm at voltage 1.7-1.72V 2 .

[0015] The present invention has the following advantages:

[0016] 1) Using α-MoO3 and Fe(NO3)3·9H2O as precursors, P-MoO2 / P-Fe3O4 heterostructured nanobelts were prepared by phosphating process, and a new synthesis route for P-MoO2 / P-Fe3O4 heterostructured nanobelts was developed.

[0017] 2) P-MoO2 / P-Fe3O4 heterostructure nanobelts have good performance in electrocatalytic water oxidation and electrocatalytic water decomposition reactions.

[0018] 3) The present invention has the advantages of being simple and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 These are the characterization results of P-MoO2 / P-Fe3O4 heterostructure nanobelts; (a) XRD, (b, c) SEM, (df) TEM, (gj) Mapping of P, Mo, O, and Fe. DETAILED DESCRIPTION

[0020] The following examples are used to further illustrate the present invention, but are not intended to limit the present invention.

[0021] Example 1

[0022] A preparation method of a P-MoO2 / P-Fe3O4 heterostructure nanobelt comprises the following steps: dissolving 1.4 g of α-MoO3 powder in 11 mL of H2O2 solution, reacting the mixture at 170°C for 12 h by a hydrothermal synthesis method, centrifuging the reaction product, and drying the mixture to obtain an α-MoO3 nanobelt having a width of 90-260 nm and a length of 500-6000 nm; then grinding a mixture of 25 mg of α-MoO3 nanobelt and 25 mg of Fe(NO3)3·9H2O uniformly and then placing the mixture in a porcelain boat; taking 1 g of NaH2PO2·H2O was placed in another porcelain boat, and the two porcelain boats were placed in a tube furnace, with the porcelain boat containing NaH2PO2·H2O placed upstream, and heated at 350°C for 2h in an Ar atmosphere with a flow rate of 20mL / min to obtain P-MoO2 / P-Fe3O4 heterostructure nanobelts with a diameter of 140-240nm and a length of 400-6500nm, with a P / Mo / Fe molar ratio of 1:10:0.05. The P-MoO2 / P-Fe3O4 heterostructure nanobelts, Nafion, and ethanol were mixed in a ratio of 5mg, 25μL, and 500μL, and 0.6mg / cm 2 The mixed solution was applied to the Ni electrode and used in the electrocatalytic water oxidation reaction and the electrocatalytic water decomposition reaction; in the electrocatalytic water oxidation reaction, the current density was 10mA / cm at a voltage of 1.5V. 2 ; Electrocatalytic water splitting reaction, current density 10mA / cm at voltage 1.72V 2 .

[0023] Example 2

[0024] A preparation method of a P-MoO2 / P-Fe3O4 heterostructure nanobelt comprises the following steps: dissolving 0.5 g of α-MoO3 powder in 5 mL of H2O2 solution, reacting at 140°C for 2 h by a hydrothermal synthesis method, centrifuging the reaction product, and drying to obtain an α-MoO3 nanobelt with a width of 90-300 nm and a length of 400-6000 nm; then grinding a mixture of 20 mg of α-MoO3 nanobelt and 20 mg of Fe(NO3)3·9H2O uniformly, and then placing the mixture in a porcelain boat; taking 0.5 g of NaH2PO2·H2O was placed in another porcelain boat, and the two porcelain boats were placed in a tube furnace, with the porcelain boat containing NaH2PO2·H2O placed upstream, and heated at 200°C for 1 h in an Ar atmosphere with a flow rate of 10 mL / min to obtain P-MoO2 / P-Fe3O4 heterostructure nanobelts with a diameter of 120-300 nm and a length of 350-7000 nm, with a P / Mo / Fe molar ratio of 2:13:2. The P-MoO2 / P-Fe3O4 heterostructure nanobelts, Nafion, and ethanol were mixed in a ratio of 5 mg, 25 μL, and 500 μL, and 0.6 mg / cm 2The mixed solution was applied to the Ni electrode and used in the electrocatalytic water oxidation reaction and the electrocatalytic water decomposition reaction; in the electrocatalytic water oxidation reaction, the current density was 10mA / cm at a voltage of 1.48V. 2 ; Electrocatalytic water splitting reaction, current density 10mA / cm at voltage 1.71V 2 .

[0025] Example 3

[0026] A method for preparing a P-MoO2 / P-Fe3O4 heterostructure nanobelt comprises the following steps: dissolving 2g of α-MoO3 powder in 20mL of H2O2 solution, reacting at 200°C for 24h by a hydrothermal synthesis method, centrifuging the reaction product, and drying to obtain an α-MoO3 nanobelt with a width of 100-300nm and a length of 400-5000nm; then grinding a mixture of 40mg of α-MoO3 nanobelt and 40mg of Fe(NO3)3·9H2O uniformly, and then placing the mixture in a porcelain boat; taking 2g of NaH2PO2·H2O was placed in another porcelain boat, and the two porcelain boats were placed in a tube furnace, with the porcelain boat containing NaH2PO2·H2O placed upstream, and heated at 400°C for 5 h in an Ar atmosphere with a flow rate of 30 mL / min to obtain P-MoO2 / P-Fe3O4 heterostructure nanobelts with a diameter of 120-240 nm and a length of 350-6500 nm, with a P / Mo / Fe molar ratio of 1.5:11:1.5. The P-MoO2 / P-Fe3O4 heterostructure nanobelts, Nafion, and ethanol were mixed in a ratio of 5 mg, 25 μL, and 500 μL, and 0.6 mg / cm 2 The mixed solution was applied to the Ni electrode and used in the electrocatalytic water oxidation reaction and the electrocatalytic water decomposition reaction; in the electrocatalytic water oxidation reaction, the current density was 10mA / cm at a voltage of 1.49V. 2 ; Electrocatalytic water splitting reaction, current density 10mA / cm at voltage 1.7V 2 .

Claims

1. A method for preparing a P-MoO2 / P-Fe3O4 heterostructure nanobelt, characterized in that: The following steps are involved: Dissolve 0.5-2g α-MoO3 powder in 5-20mL H2O2 solution, react at 140-200℃ for 2-24h by hydrothermal synthesis method, centrifuge the reaction product, and dry to obtain α-MoO3 nanobelts with a width of 90-300nm and a length of 400-6000nm; then grind 20-40mg of the above α-MoO3 nanobelts and 20-40mg Fe(NO3)3·9H2O mixture evenly, and then put it into a porcelain boat; take 0.5-2g NaH2PO2·H2O and put it into another porcelain boat, put the two porcelain boats into a tubular furnace, and place the porcelain boat containing NaH2PO2·H2O in the upstream, and heat at 10-30mL / min. Heating at 200-400°C in an Ar atmosphere for 1-5 hours obtains P-MoO2 / P-Fe3O4 heterostructure nanobelts with a width of 120-300nm and a length of 350-7000nm, and a P / Mo / Fe molar ratio of (1-2):(10-13):(0.05-2). The MoO2 crystal phase in the P-MoO2 / P-Fe3O4 heterostructure nanobelts belongs to the standard card JCPDS#32-0671, and the Fe3O4 crystal phase belongs to the standard card JCPDS#19-0629.

2. An application of the P-MoO2 / P-Fe3O4 heterostructure nanobelt prepared by the preparation method of claim 1 in electrocatalysis; electrocatalytic water oxidation reaction, the current density is 10mA / cm when the voltage is 1.48-1.5V 2 ; Electrocatalytic water splitting reaction, current density 10mA / cm at voltage 1.7-1.72V 2 .

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