A preparation method of nitrogen and phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material for water treatment

Abstract

The application relates to a preparation method of nitrogen-phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material for water treatment, in particular to the following steps: mixing alpha-MoO3 powder and H2O2, hydrothermally synthesizing alpha-MoO3 nanosheets; dispersing the alpha-MoO3 nanosheets in water, mixing and dispersing glucose and melamine phosphate in water, mixing the two aqueous solutions, putting foamed NiFe into the mixed solution, heating and evaporating water under oil bath conditions to form a slurry material, then putting the slurry material into a tube furnace, and roasting under Ar atmosphere to obtain nitrogen-phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material; and the application of the prepared nitrogen-phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material in a water treatment reaction.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a nitrogen-phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material for water treatment, and belongs to the fields of material preparation and application. BACKGROUND

[0002] A large number of studies have shown that finding and developing green energy can effectively alleviate environmental pollution caused by overuse of fossil fuels. Hydrogen energy is considered an important energy carrier. Electrocatalytic decomposition of water is an effective path to produce hydrogen and oxygen, but slow kinetics reduces the efficiency of water electrolysis. So far, Pt-based materials and RuO2-based materials are important water decomposition catalysts. For example, Gao's team used Ni(NO3)2·6H2O, (NH4)6Mo7O 24 ·4H2O, H2PtCl6, NaBH4, etc. to construct Pt / MoO2 / Ni(OH)2 / Ni, which catalyzes water reduction to produce hydrogen under KOH electrolyte, with a voltage of 18 mV at 10 mA / cm 2 Kundu's group used Co(OAc)2·4H2O, RuCl3·xH2O, PVP, BTC, methanol, ethanol, etc. to synthesize Co-doped RuO2 nanorods, which catalyze water oxidation to produce oxygen under KOH electrolyte, with a voltage of 238 mV at 10 mA / cm 2 Low reserves limit its wide application, so finding non-noble metal bifunctional catalysts has become a research focus.

[0003] Transition metal oxides are considered a class of efficient electrocatalysts due to their high content and high catalytic efficiency. Jiang's group used C6H5Na3O7·2H2O, (NH4)2Fe(SO4)2·6H2O, Na2WO4·2H2O, NiSO4·6H2O, NH4F·H2O, NaH2PO2·H2O, etc. to construct a Ni-Fe-P-WO3 / NF composite, which catalyzes water oxidation to produce oxygen under KOH electrolyte, with a voltage of 218 mV at 10 mA / cm 2 Kurungot's group used (NH4)6Mo7O 24·4H2O, CH4N2S, N2H4·H2O, KOH, H2O2, NiCl2·6H2O, C, etc. to synthesize carbon-supported NiO-MoO3 composite, NiO@MoO3 / VC catalyzes water oxidation to release oxygen under KOH electrolyte, and the voltage is 280mV (ACS Appl. Energy Mater. 2019, 2, 4987-4998). Chong team uses Mo powder, Co(NO3)2·6H2O, DMF, H2O2, KOH, HCl, etc. to synthesize ZIF67@MoO3@NF, which catalyzes water decomposition to release oxygen and hydrogen under KOH electrolyte, and the voltage is 1.58V (Int. J. Hydrogen Energy, 2022, 47, 9606-9615). Based on the above research results, the controllable modulation of MoO3-based materials forms a nitrogen and phosphorus co-doped carbon-encapsulated MoO3-Mo2C heterostructure material, which effectively breaks the H-OH bond, and has important research value. 2 2 SUMMARY

[0004] The present application aims to provide a preparation method of a nitrogen and phosphorus co-doped carbon-encapsulated MoO3-Mo2C heterostructure material for water treatment.

[0005] Based on the above purpose, the technical scheme of the present application is as follows:

[0006] (1) Preparation of nitrogen and phosphorus co-doped carbon-encapsulated MoO3-Mo2C heterostructure material: mix 1-2g of α-MoO3 powder with 10-20mL of H2O2, and hydrothermally synthesize α-MoO3 nanosheets at 150-200℃; disperse 1-2g of α-MoO3 nanosheets in 10-20mL of water, mix and disperse 0.5-1.2g of glucose and 0.4-0.6g of phosphonium cyanamide in 10-20mL of water, mix the two aqueous solutions, put the foamed NiFe into the mixed solution, and evaporate water to form a slurry under oil bath heating at 90-120℃, then put the slurry into a tube furnace, and calcine at 600-800℃ for 1-3h under Ar atmosphere, to obtain a nitrogen and phosphorus co-doped carbon-encapsulated MoO3-Mo2C heterostructure material. The above preparation method, the α-MoO3 belongs to standard card JCPDS # 35-0609; the Mo2C belongs to standard card JCPDS # 45-1013.

[0007] (2) Application of the nitrogen and phosphorus co-doped carbon-encapsulated MoO3-Mo2C heterostructure material prepared by the above preparation method in water treatment reaction; in the electrocatalytic decomposition of water, the reaction current density is 10mA / cm 2 ​​, voltage is 1.55-1.64V; in photocatalytic dye wastewater, methylene blue concentration is 0.1-1ppm, reaction time is 6-10h, removal rate is 100%.

[0008] The present application has the following advantages:

[0009] (1) A new synthesis path of nitrogen and phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material is provided.

[0010] (2) The nitrogen and phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material exhibits high catalytic ability in water treatment reaction. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is the characterization result of α-MoO3nanosheet.

[0012] Figure 2 is the XRD, TEM and N, P, C, Mo, O Mapping characterization result of nitrogen and phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material. DETAILED DESCRIPTION

[0013] The following examples are used to further illustrate the present application, but do not limit the present application.

[0014] Example 1

[0015] 1g of α-MoO3powder is mixed with 10mL of H2O2, and α-MoO3nanosheet is hydrothermally synthesized at 150℃; 1g of α-MoO3nanosheet is dispersed in 10mL of water, 0.5g of glucose and 0.4g of phosphonium cyanamide are mixed and dispersed in 10mL of water, the above two aqueous solutions are mixed, the foamed NiFe is put into the above mixed solution, and the slurry is formed by heating and evaporating water under oil bath at 90℃, then the slurry is put into a tube furnace, and the nitrogen and phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material is obtained by calcining at 600℃ for 1h under Ar atmosphere. The preparation method described above, the α-MoO3belongs to standard card JCPDS # 35-0609; the Mo2C belongs to standard card JCPDS # 45-1013. The nitrogen and phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material prepared is used for water treatment; in electrocatalytic decomposition of water, the reaction current density is 10mA / cm 2 , voltage is 1.55V; in photocatalytic dye wastewater, methylene blue concentration is 0.1ppm, reaction time is 6h, removal rate is 100%.

[0016] Example 2

[0017] 2 g of a-MoO3 powder was mixed with 20 mL of H2O2, and a-MoO3 nanosheets were hydrothermally synthesized at 200 °C; 2 g of a-MoO3 nanosheets was dispersed in 20 mL of water, 1.2 g of glucose and 0.6 g of phosphorus cyanamide were mixed and dispersed in 20 mL of water, the above two aqueous solutions were mixed, the foam NiFe was put into the above mixed solution, the water was evaporated to form a slurry under the condition of oil bath at 120 °C, and then the slurry was put into a tube furnace, and the slurry was calcined at 800 °C for 3 h under Ar atmosphere, to obtain a nitrogen and phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material. In the above preparation method, the a-MoO3 belongs to standard card JCPDS # 35-0609; the Mo2C belongs to standard card JCPDS # 45-1013. The nitrogen and phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material prepared was used for water treatment; in the electrocatalytic decomposition of water, the reaction current density was 10 mA / cm2, and the voltage was 1.64 V; in the photocatalytic methylene blue in dye wastewater, the methylene blue concentration was 1 ppm, the reaction time was 10 h, and the removal rate was 100%. 2

[0018] Example 3

[0019] 2 g of a-MoO3 powder was mixed with 20 mL of H2O2, and a-MoO3 nanosheets were hydrothermally synthesized at 200 °C; 2 g of a-MoO3 nanosheets was dispersed in 20 mL of water, 1.2 g of glucose and 0.6 g of phosphorus cyanamide were mixed and dispersed in 20 mL of water, the above two aqueous solutions were mixed, the foam NiFe was put into the above mixed solution, the water was evaporated to form a slurry under the condition of oil bath at 120 °C, and then the slurry was put into a tube furnace, and the slurry was calcined at 800 °C for 3 h under Ar atmosphere, to obtain a nitrogen and phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material. In the above preparation method, the a-MoO3 belongs to standard card JCPDS # 35-0609; the Mo2C belongs to standard card JCPDS # 45-1013. The nitrogen and phosphorus co-doped carbon encapsulated MoO3-Mo2C heterostructure material prepared was used for water treatment; in the electrocatalytic decomposition of water, the reaction current density was 10 mA / cm2, and the voltage was 1.64 V; in the photocatalytic methylene blue in dye wastewater, the methylene blue concentration was 1 ppm, the reaction time was 10 h, and the removal rate was 100%. 2 , the voltage was 1.6 V; in the photocatalytic methylene blue in dye wastewater, the methylene blue concentration was 1 ppm, the reaction time was 10 h, and the removal rate was 100%.​

Claims

1. A method for preparing a nitrogen-phosphorus co-doped carbon-encapsulated MoO3-Mo2C heterostructure material, characterized in that, Includes the following steps: 1-2 g of α-MoO3 powder was mixed with 10-20 mL of H2O2 and hydrothermally synthesized into α-MoO3 nanosheets at 150-200 °C. 1-2 g of α-MoO3 nanosheets were dispersed in 10-20 mL of water. 0.5-1.2 g of glucose and 0.4-0.6 g of melamine phosphate were mixed and dispersed in 10-20 mL of water. The two aqueous solutions were then mixed, and foamed NiFe was added to the mixture. The mixture was heated at 90-120 °C in an oil bath to evaporate the water and form a slurry. The slurry was then placed in a tube furnace and calcined at 600-800 °C for 1-3 h under an Ar atmosphere to obtain a nitrogen-phosphorus co-doped carbon-encapsulated MoO3-Mo2C heterostructure material. The α-MoO3 is classified under standard card JCPDS#35-0609; the Mo2C is classified under standard card JCPDS#45-1013.

2. The application of a nitrogen-phosphorus co-doped carbon-encapsulated MoO3-Mo2C heterostructure material prepared by the method described in claim 1 in water treatment reactions; in electrocatalytic water splitting, the reaction current density is 10 mA / cm². 2 The voltage was 1.55-1.64 V; the methylene blue concentration in the photocatalytic dye wastewater was 0.1-1 ppm, the reaction time was 6-10 h, and the removal rate was 100%.

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