阅读说明：本技术 一种MOF基MoP-Cu3P过渡金属磷化物异质结光催化剂 (MOF-based MoP-Cu3P transition metal phosphide heterojunction photocatalyst ) 是由 曹江行 于 2020-05-25 设计创作，主要内容包括：本发明涉及一种MOF基MoP-Cu<Sub>3</Sub>P过渡金属磷化物异质结光催化剂及制备方法,一步法制备MOF基MoP-Cu3P过渡金属磷化物异质结催化剂,MOF为金属有机框架材料,采用MOF的衍生物作为前驱体制备高度分散的MOF基MoP-Cu<Sub>3</Sub>P过渡金属磷化物纳米材料。MoP-Cu<Sub>3</Sub>P过渡金属磷化物复合材料由MOF的衍生物与磷酸二氢钠高温反应合成,利用MoP高的金属导电性、良好的H<Sup>+</Sup>传递能力、出色的活性作为助催化剂来增强和吸收并加速半导体载流子分离提高析氢效率,Cu<Sub>3</Sub>P良好光电性能与MoP金属磷化物复合,克服其载体重组导致严重析氢转化效率下降的问题；利用MoP和Cu<Sub>3</Sub>P之间的紧密接触将建立肖特基结,加速载流子的分离和转移。(The invention relates to a MOF-based MoP-Cu 3 A P transition metal phosphide heterojunction photocatalyst and a preparation method thereof are provided, the MOF-based MoP-Cu3P transition metal phosphide heterojunction catalyst is prepared by a one-step method, MOF is a metal organic framework material, and a derivative of MOF is adopted as a precursor to prepare highly dispersed MOF-based MoP-Cu 3 P transition metal phosphide nano-material. MoP-Cu 3 The P transition metal phosphide composite material is synthesized by reacting derivatives of MOF with sodium dihydrogen phosphate at high temperature, and utilizes the high metal conductivity and good H of the MoP + Transfer capability, excellent activity as a promoter to enhance and absorb and accelerate semiconductor carrier separation to improve hydrogen evolution efficiency, Cu 3 P has good photoelectric property and is compounded with MoP metal phosphide, so that the problem of serious reduction of hydrogen evolution conversion efficiency caused by carrier recombination is solved; using MoP and Cu 3 The close contact between P will establish Schottky junction to accelerate the carrierSeparation and transfer.)

1. MOF-based MoP-Cu₃P transition metal phosphide heterojunction photocatalyst, characterized in that the MOF group MoP-Cu₃P is a molecular cage structure, and the cage is Cu₃P composition, Cu₃P molecular cage wraps MOP, and the MOF group MoP-Cu₃The precursor of P is a derivative of a metal organic framework material, and the precursor organic framework derivative is subjected to pre-acidification treatment.

2. The MOF-based MoP-Cu of claim 1₃The P transition metal phosphide heterojunction photocatalyst is characterized in that the derivative of the MOF is as follows: NENU-5 (a MOF derivative containing Cu and Mo), HKUST-1 (a MOF derivative containing only Cu).

3. The MOF-based MoP-Cu of claim 1₃P transition metal phosphide heterojunction photocatalyst, characterized in that, the MoP-Cu₃P is a transition metal phosphide composite material, and the precursor is as follows: phosphomolybdic acid hydrate (PMo)₁₂) Copper acetate monohydrate (Cu)²⁺) L-glutamic acid, wherein phosphomolybdic acid hydrate (PMo)¹²) Copper acetate monohydrate (Cu)²⁺) The mass percentage of the L-glutamic acid is as follows: 10-20%, 20-35%, 45-70%. PMo phosphomolybdic acid₁₂Is a polyoxometallate, mainly provides a molybdenum source, and is packaged in Cu₃P octahedron inside the cavity.

4. The MOF-based MoP-Cu of claim 1₃A P-transition metal phosphide heterojunction photocatalyst characterized in that: preparation of the precursor of the MoP-Cu3P hybridThe stock solution had a pH of 3.

5. The MOF-based MoP-Cu of claim 1₃A preparation method of a P transition metal phosphide heterojunction photocatalyst,

the specific method comprises the following steps:

1) phosphomolybdic acid hydrate (PMo)₁₂) Copper acetate monohydrate (Cu)²⁺) Dissolving L-glutamic acid in 50mL of deionized water, and stirring at room temperature for 1-3h to obtain a clear solution;

2) dissolving 1,3, 5-benzene tricarboxylic acid (BTC) in ethanol, and stirring for 1-3h at room temperature to obtain a clear solution.

Adding the solution of step 2) into the clear solution A of step 1) and stirring vigorously for 14-28 h;

3) centrifuging the product obtained in the step 3), washing with ethanol for 3 times, washing with deionized water for 1 time, and drying the precipitate to obtain MOF NENU-5 derivatives;

4) and 4) placing the product at the outlet end of the double-temperature-zone tubular furnace, placing sodium dihydrogen phosphate at the inlet end, pumping the pressure of the tubular furnace to 100Pa, introducing Ar gas, and carrying out high-temperature synthesis reaction.

6. The MOF-based MoP-Cu of claim 5₃The preparation method of the P transition metal phosphide heterojunction photocatalyst is characterized in that Ar gas is introduced into the double-temperature-zone tubular furnace 1h before the reaction, and the speed is 80 s.c.c.m.

7. The MOF-based MoP-Cu of claim 5₃The preparation method of the P transition metal phosphide heterojunction photocatalyst is characterized in that in the step 4), the temperature of the gas inlet end of the double-temperature-zone tubular furnace is increased to 80-100 ℃ within 20 minutes, the temperature is maintained for 30 minutes, the temperature is increased to 150-200 ℃ within 20 minutes, the temperature is maintained for 30 minutes, the temperature is decreased to 130-150 ℃ within 20 minutes, the temperature is maintained for 30 minutes, and then the temperature is cooled to room temperature.

Technical Field

The invention belongs to the field of environment-friendly photocatalytic hydrogen production, and particularly relates to MOF-based MoP-Cu₃A P transition metal phosphide heterojunction photocatalyst.

Background

Excessive consumption of fossil fuels poses a series of energy and environmental problems, and hydrogen, a clean renewable energy source with high calorific value, will likely replace fossil fuels. Photocatalytic water splitting is considered to be the most promising method for obtaining hydrogen, and to date, many effective photocatalysts have been developed with important roles. Wherein the transition metal phosphide has good electrical conductivity and excellent catalytic activity, has been proven to be an excellent catalyst for Hydrogen Evolution Reaction (HER), such as Ni₂P，CoP，Co₂P， FeP，Cu₃P, WP and MoP. Wherein, Cu₃P has good photoelectric property and abundant resources, and has great research and development value when being used as a catalyst material for photocatalytic water decomposition. However, it also has some limitations, e.g. pure Cu₃P usually exhibits severe carrier recombination, which has a severe effect on photocatalytic activity. Pure Cu₃The poor photocatalytic performance of P has prompted the development of appropriate strategies to improve its photocatalytic performance. Numerous studies have demonstrated that the construction of heterojunctions is a universally effective method for inducing carrier separation and migration.

Disclosure of Invention

Aiming at the problems of low hydrogen evolution efficiency and carrier recombination in the single catalyst catalysis process of the existing hydrogen evolution photocatalyst, the invention provides a MOF-based MoP-Cu with simple and convenient operation and high hydrogen evolution rate₃A P transition metal phosphide heterojunction photocatalyst.

The technical scheme adopted by the invention for realizing the purpose is as follows:

preparing MOF-based MoP-Cu3P transition metal phosphide heterojunction catalyst by one-step method, wherein MOF is metal organic framework material, and preparing highly dispersed MOF-based MoP-Cu by taking derivative of MOF as precursor₃P transition metal phosphide nano-material. MoP-Cu₃The P transition metal phosphide composite material is synthesized by reacting derivatives of MOF with sodium dihydrogen phosphate at high temperature, and utilizes the high metal conductivity and good H of the MoP⁺Transfer capability, excellent activity as a promoter to enhance and absorb and accelerate semiconductor carrier separation to improve hydrogen evolution efficiency, Cu₃P has good photoelectric property and is compounded with MoP metal phosphide, so that the problem of serious reduction of hydrogen evolution conversion efficiency caused by carrier recombination is solved; using MoP and Cu₃The close contact between P will create a schottky junction, accelerating the separation and transfer of carriers.

Preferably, the derivative of MOF is: NENU-5 (a MOF derivative containing Cu and Mo), HKUST-1 (a MOF derivative containing only Cu). Cu in NENU-5, HKUST-1²⁺Not only acts as a copper source, but also is combined with organic ligands of MOF derivatives to form octahedrons to strengthen MoP-Cu₃P binding ability, effective extension of MoP-Cu₃The service life of P.

Preferably, the MoP-Cu3P is a transition metal phosphide composite material, and the precursor is as follows: phosphomolybdic acid hydrate (PMo)₁₂) Copper acetate monohydrate(Cu²⁺) L-glutamic acid, wherein phosphomolybdic acid hydrate (PMo)₁₂) Copper acetate monohydrate (Cu)²⁺) The mass percentage of the L-glutamic acid is as follows: 10-20%, 20-35%, 45-70%. PMo phosphomolybdic acid₁₂Is a polyoxometallate, mainly provides a molybdenum source, and is packaged in Cu₃P octahedron inside the cavity.

Preferably, the preparation solution of the precursor of the MoP-Cu3P hybrid has a pH of 3, is pre-acidified and is subjected to a pre-acidification treatment in H⁺At a higher concentration, Cu is promoted²⁺To MoP-Cu₃And (4) converting P.

The invention also provides MOF-based MoP-Cu₃The preparation method of the P transition metal phosphide heterojunction photocatalyst comprises the following steps:

1) phosphomolybdic acid hydrate (PMo)₁₂) Copper acetate monohydrate (Cu)²⁺) And L-glutamic acid is dissolved in 50mL of deionized water, and the mixture is stirred for 1 to 3 hours at room temperature to obtain a clear solution.

2) Dissolving 1,3, 5-benzene tricarboxylic acid (BTC) in ethanol, and stirring for 1-3h at room temperature to obtain a clear solution.

3) Adding the solution of step 2) into the clear solution A of step 1) and stirring vigorously for 14-28 h;

4) centrifuging the product obtained in the step 3), washing with ethanol for 3 times, washing with deionized water for 1 time, and drying the precipitate to obtain a MOFNENU-5 derivative;

5) placing the product of the step 4) at the outlet end of a double-temperature-zone tubular furnace, placing sodium dihydrogen phosphate at the inlet end, pumping the pressure of the tubular furnace to 100Pa, introducing Ar gas, and carrying out high-temperature synthesis reaction;

preferably, in the two-temperature zone tubular furnace, Ar gas is introduced at a rate of 80 s.c.c.m.1 h before the reaction.

Preferably, the temperature of the gas inlet end of the two-temperature zone tubular furnace is increased to 100 ℃ within 20 minutes, the temperature is maintained for 30 minutes, the temperature is increased to 200 ℃ within 20 minutes, the temperature is maintained for 30 minutes, the temperature is decreased to 150 ℃ within 20 minutes, the temperature is maintained for 30 minutes, and then the temperature is cooled to the room temperature.

Compared with the prior art, the invention has the following advantages:

1) the derivative of MOF is selected from NENU-5 (also a MOF derivative of Cu and Mo) and HKUST-1 (only a MOF derivative of Cu), and the prepared MoP-Cu3P has higher photocatalytic activity and outstanding structural stability compared with a single catalyst.

2) The close contact between the MoP and the Cu3P establishes a Schottky junction, accelerates the separation and transfer of carriers and improves the hydrogen evolution efficiency;

3) the dual-zone tube furnace is synchronously regulated and controlled in a non-isothermal way, and the prepared MOFs composite MoP-Cu3P transition metal phosphide heterojunction catalyst has a stable octahedral structure, so that the service life of the catalyst is prolonged;

4)Cu²⁺not only acts as a copper source, but also combines with organic ligands of MOF derivatives to form octahedrons, and constructs the stable MOF-based MoP-Cu3P transition metal phosphide heterojunction photocatalyst.

5) The MOF-based MoP-Cu3P transition metal phosphide heterojunction photocatalyst is prepared by a one-step method, and the method is simple and controllable and is easy to popularize.

Drawings

FIG. 1 is a scanning electron microscope image of a MOFs-based MoP-Cu3P composite material;

FIG. 2 is a hydrogen production diagram of MoP, CuP3, MoP/CuP3 and MOFs-based MoP-Cu3P catalysts;

FIG. 3 is a diagram of hydrogen production rates of MoP, CuP3, MoP/CuP3 and MOFs-based MoP-Cu3P catalysts;

FIG. 4 is a graph of photocurrent density versus time under visible light for MoP, CuP3, MOFs based MoP-Cu3P catalysts.

Detailed Description

For further understanding of the contents, features and effects of the present invention, the following examples are given, but the preparation scheme of the present invention is not limited to these examples, and the following detailed descriptions are given: