Cu@ni se X Quantum dot electrocatalyst and its application in biomass conversion

Abstract

The application discloses a Cu@NiSe X The application discloses a quantum dot electrocatalyst and application thereof in biomass conversion, and belongs to the technical field of electrochemical synthesis and catalysis. X The quantum dot catalyst is used for regulating and controlling electro-oxidation performance. Cu as a substitutional acceptor doping ion makes charge in the catalyst redistribute, regulates and controls charge transfer capacity and electronic structure of the catalyst, so that more Ni 3+ active sites with low electron cloud density are generated. 3+ The Ni 3+ active sites have more excellent substrate adsorption capacity and oxidation capacity, so that reaction overpotential is effectively reduced and FDCA yield is improved, and the target product acid compound has higher selectivity and yield, and the catalyst has higher stability and can be repeatedly used.

Description

Technical Field

[0001] This invention relates to the field of electrochemical synthesis and catalysis technology, specifically to a Cu@NiSe... X Quantum dot electrocatalysts and their applications in biomass conversion. Background Technology

[0002] Biomass is a novel renewable non-fossil energy source. Its abundant reserves and convenient storage and transportation offer a potential alternative energy source for alleviating the energy crisis. It also possesses great potential as a platform molecule for producing high-value-added raw materials. For example, 5-hydroxymethylfurfural (HMF) and furfuryl alcohol (FA) are isomerization dehydration products extracted from cellulosic biomass, and their oxidation products can replace terephthalic acid in the synthesis of biodegradable polymers. However, traditional methods require precious metal catalysts under high pressure, high reaction temperature, and toxic oxidants, causing severe environmental pollution and resulting in high costs and energy consumption. Electrochemical catalytic oxidation of biomass conversion meets the requirements of green chemistry; however, it currently faces challenges such as product diversity, low conversion rate, high reaction potential, complex catalyst preparation, and lack of reusability. Therefore, finding a suitable catalyst to improve the selectivity of reaction products and the conversion rate of reactants, while simultaneously reducing the reaction potential and enabling reusability, is essential and crucial.

[0003] Therefore, developing low-cost non-precious metal electrocatalysts is of great significance for promoting the practical application of electrocatalytic biomass oxidation systems. However, the high reaction overpotential applied by non-precious metal electrocatalysts during the catalytic biomass electrooxidation reaction leads to high energy consumption, which seriously hinders the practical large-scale application of electrocatalytic biomass oxidation. Therefore, further reducing the reaction overpotential while achieving high levels of target product yield and selectivity is a challenging research topic. Electronic structure engineering is considered an effective method for designing highly efficient electrocatalysts. Research results in electronic structure engineering show that changes in the electronic structure of active materials can affect the adsorption / desorption capacity of reactants and products in electrocatalytic reactions, thereby regulating their electrocatalytic ability (e.g., reaction overpotential, target product yield, etc.). By doping with heteroatoms, the electronic structure of active materials can be altered, thereby changing the intrinsic properties of the material to prepare highly active electrocatalysts for biomass conversion. Summary of the Invention

[0004] The purpose of this invention is to provide a Cu@NiSe X Quantum dot electrocatalysts and their applications in biomass conversion, specifically the Cu@NiSe X Quantum dot electrocatalysts modulate the charge transfer capability and electronic structure of catalysts, thereby generating more Ni with low electron cloud density. 3+ Active sites, enabling Ni 3+The active sites exhibit superior substrate adsorption and oxidation capabilities. When applied to the electrochemical catalytic oxidation of 5-hydroxymethylfurfural and furfuryl alcohol, the catalyst demonstrates low reaction potential, high activity, high selectivity, and high stability.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A Cu@NiSeX quantum dot catalyst is characterized by having a hexagonal nickel selenide mineral phase structure and nanoparticles with a particle size of 3~4 nm.

[0006] According to claim 1, the Cu@NiSeX quantum dot catalyst is characterized in that: the doping of Cu heteroatoms into the NiSex lattice causes a positive shift of the Ni2p binding energy by 0.1~0.5 eV, and a positive shift of the Se3d binding energy by 0.3~0.5 eV.

[0007] A Cu@NiSeX quantum dot electrocatalyst and its application in biomass conversion, characterized in that: the biomass electro-oxidation conversion reaction uses 5-hydroxymethylfurfural or furfuryl alcohol as reactants, and is carried out in a two-chamber electrolytic cell separated by a proton exchange membrane using a three-electrode system, wherein the working electrode in the three-electrode system is the Cu@NiSeX quantum dot catalyst of claim 1.

[0008] The biomass electro-oxidation conversion reaction according to claim 3 is characterized in that: the concentration of reactants is 1~2 mol / L, and the reaction voltage is 0.8~1.35V vs. RHE.

[0009] The biomass electro-oxidation conversion reaction according to claim 3 is characterized in that the yield and selectivity of the target products 2,5-furan carboxylic acid and furfural are 95-99%.

[0010] The principle of this invention is as follows: The Cu@NiSex nanoparticle catalyst of this invention can have its catalytic performance controlled by changing the doping amount of Cu heteroatoms. Cu, as a substitutional acceptor dopant ion, not only participates in the composition of the material's electronic structure but also redistributes the charge within the catalyst, resulting in the presence of more Ni atoms with low electron cloud density in the catalyst. 3+ Active sites. Furthermore, the introduction of Cu heteroatoms further enhances the catalyst's charge transfer capability, resulting in improved oxidation performance and higher activity.

[0011] The advantages of this invention are as follows: 1. This invention uses Cu@NiSex nanoparticle catalysts as catalysts for the electrochemical catalytic oxidation of biomass to prepare high-value-added chemicals, exhibiting excellent activity and high selectivity. The yields and selectivity of the target products 2,5-furan carboxylic acid and furfural are as high as 95-99%. 2. The reaction is carried out at room temperature, without the need for any organic solvents, and is non-toxic and pollution-free, meeting green chemistry standards. 3. The Cu@NiSex nanoparticle catalyst is synthesized using a hydrothermal method. This preparation method is simple and easy to operate, requires short time, is low in cost, and has good catalyst reusability. Attached Figure Description

[0012] Figure 1 This is a transmission electron microscope image of the Cu@NiSex nanoparticles prepared in this invention.

[0013] Figure 2 The conversion of 5-hydroxymethylfurfural (HMF) and the yield of 2,5-furan carboxylic acid (FDCA) are given by Cu@NiSex, NiSex and CuSex catalysts.

[0014] Figure 3 The conversion rates of furfuryl alcohol and the yield of furfural are given by Cu@NiSex, NiSex and CuSex catalysts. Detailed Implementation

[0015] The present invention will be described in detail below with reference to the embodiments.

[0016] Example 1 (1) Preparation of Se precursor solution: Add a certain amount of deionized water (about 30 mL) to an Erlenmeyer flask and purge it with N2 for 30 min to remove O2 from the system. Then add 0.57 g NaBH4 to the Erlenmeyer flask and wait for it to completely dissolve before adding 0.396 g Se powder. Stir continuously with a magnetic force under nitrogen atmosphere until the black Se powder completely disappears and no more bubbles are generated. At this point, a colorless and transparent NaHSe solution is obtained. Seal the solution for later use.

[0017] (2) Preparation of Ni precursor solution: Take a certain amount of deionized water (about 120 mL) and add it to a beaker. Under magnetic stirring, add 1.09 g Ni(NO3)2·6H2O, a certain amount of Cu(NO3)2·3H2O and 1040 µL of mercaptoacetic acid ligand in sequence, and use 2 mol L -1 The pH of the solution was adjusted to 11 with NaOH solution, and the total volume of the solution was adjusted to 170 mL to obtain the Ni precursor solution. This solution was then transferred to a three-necked flask and N2 was bubbled through it for approximately 60 min to remove O2 from the system.

[0018] (3) Pour the Se precursor solution into a three-necked flask containing the Ni precursor solution, heat in a water bath at 90 °C for 3 h, then pour the reacted liquid into a beaker, add an appropriate amount of acetone, let stand for 4 h, wash the precipitate, centrifuge, and dry to obtain Cu@NiSe. x Powder sample ( Figure 1 ).

[0019] (4) Electrochemical performance test: The obtained Cu@NiSe x The catalyst was used in the electro-oxidation of 5-hydroxymethylfurfural and the oxidation of furfural, employing a three-electrode system, Cu@NiSe. x The catalyst was used as the working electrode, a platinum sheet as the counter electrode, and a mercury / mercury oxide electrode as the reference electrode. In the two-chamber electrolytic cell, a 0.1 mol / L potassium hydroxide solution was used as the electrolyte, the reactant was 5-hydroxymethylfurfural or furfural, and the reaction voltage was 1.36 V. RHE The reaction time was 1 hour. After the reaction, the conversion rate of 5-hydroxymethylfurfural was 99%, and the yield of 2,5-furan carboxylic acid was 98%. Figure 2 The conversion rate of furfuryl alcohol was 98%, and the yield of furfural was 97.5%. Figure 3 ).

[0020] Comparative Example 1 (1) Preparation of Se precursor solution: Add a certain amount of deionized water (about 30 mL) to an Erlenmeyer flask and purge it with N2 for 30 min to remove O2 from the system. Then add 0.57 g NaBH4 to the Erlenmeyer flask and wait for it to completely dissolve before adding 0.396 g Se powder. Stir continuously with a magnetic force under nitrogen atmosphere until the black Se powder completely disappears and no more bubbles are generated. At this point, a colorless and transparent NaHSe solution is obtained. Seal the solution for later use.

[0021] (2) Preparation of Ni precursor solution: Add a certain amount of deionized water (about 120 mL) to a beaker, and under magnetic stirring, add 1.09 g Ni(NO3)2·6H2O and 1040 µL of mercaptoacetic acid ligand in sequence, and use 2 mol L -1 The pH of the solution was adjusted to 11 with NaOH solution, and the total volume of the solution was adjusted to 170 mL to obtain the Ni precursor solution. This solution was then transferred to a three-necked flask and N2 was bubbled through it for approximately 60 min to remove O2 from the system.

[0022] (3) Pour the Se precursor solution into a three-necked flask containing the Ni precursor solution, heat in a water bath at 90 °C for 3 h, then pour the reacted liquid into a beaker, add an appropriate amount of acetone, let stand for 4 h, wash the precipitate, centrifuge, and dry to obtain NiSe. x Powder sample.

[0023] (4) Electrochemical performance test: The obtained NiSe x The catalyst was used in the electro-oxidation of 5-hydroxymethylfurfural and the oxidation of furfural, employing a three-electrode system, NiSe. x The catalyst was used as the working electrode, a platinum sheet as the counter electrode, and a mercury / mercury oxide electrode as the reference electrode. In the two-chamber electrolytic cell, a 0.1 mol / L potassium hydroxide solution was used as the electrolyte, the reactant was 5-hydroxymethylfurfural or furfural, and the reaction voltage was 1.36 V. RHE The reaction time was 1 hour. After the reaction, the conversion rate of 5-hydroxymethylfurfural was 54%, and the yield of 2,5-furan carboxylic acid was 52%. Figure 2 The conversion rate of furfuryl alcohol was 48%, and the yield of furfural was 45%. Figure 3 ).

[0024] Comparative Example 2 (1) Preparation of Se precursor solution: Add a certain amount of deionized water (about 30 mL) to an Erlenmeyer flask and purge it with N2 for 30 min to remove O2 from the system. Then add 0.57 g NaBH4 to the Erlenmeyer flask and wait for it to completely dissolve before adding 0.396 g Se powder. Stir continuously with a magnetic force under nitrogen atmosphere until the black Se powder completely disappears and no more bubbles are generated. At this point, a colorless and transparent NaHSe solution is obtained. Seal the solution for later use.

[0025] (2) Preparation of Cu precursor solution: A certain amount of deionized water (about 120 mL) was added to a beaker. Under magnetic stirring, 0.906 g Cu(NO3)2·3H2O and 1040 µL of mercaptoacetic acid ligand were added sequentially, and 2 mol L⁻¹ was used to prepare the solution. -1 The pH of the solution was adjusted to 11 with NaOH solution, and the total volume of the solution was adjusted to 170 mL to obtain the Ni precursor solution. This solution was then transferred to a three-necked flask and N2 was bubbled through it for approximately 60 min to remove O2 from the system.

[0026] (3) Pour the Se precursor solution into a three-necked flask containing the Cu precursor solution, heat in a water bath at 90 °C for 3 h, then pour the reacted liquid into a beaker, add an appropriate amount of acetone, let stand for 4 h, wash the precipitate, centrifuge, and dry to obtain CuSe. x Powder sample.

[0027] (4) Electrochemical performance test: The obtained CuSe x The catalyst was used in the electro-oxidation of 5-hydroxymethylfurfural and the oxidation of furfural, employing a three-electrode system, CuSe xThe catalyst was used as the working electrode, a platinum sheet as the counter electrode, and a mercury / mercury oxide electrode as the reference electrode. In the two-chamber electrolytic cell, a 0.1 mol / L potassium hydroxide solution was used as the electrolyte, the reactant was 5-hydroxymethylfurfural or furfural, and the reaction voltage was 1.36 V. RHE The reaction time was 1 hour. After the reaction, the conversion rate of 5-hydroxymethylfurfural was 50%, and the yield of 2,5-furan carboxylic acid was 45%. Figure 2 The conversion rate of furfuryl alcohol was 42%, and the yield of furfural was 38%. Figure 3 ).

Claims

1. A Cu@NiSe X Quantum dot catalyst, characterized in that: It has a hexagonal nickel selenide mineral phase structure, and the nanoparticles have a particle size of 3~4nm.

2. The Cu@NiSe according to claim 1 X Quantum dot catalyst, characterized in that: The doping of Cu heteroatoms into the NiSex lattice causes a positive shift in the Ni2p binding energy of 0.1–0.5 eV, and a positive shift in the Se3d binding energy of 0.3–0.5 eV.

3. A Cu@NiSeX quantum dot electrocatalyst and its application in biomass conversion, characterized in that: The biomass electro-oxidation conversion reaction uses 5-hydroxymethylfurfural or furfuryl alcohol as reactants and is carried out in a two-chamber electrolytic cell separated by a proton exchange membrane using a three-electrode system. The working electrode in the three-electrode system is the Cu@NiSe of claim 1. X Quantum dot catalysts.

4. The biomass electro-oxidation conversion reaction according to claim 3, characterized in that: The concentration of reactants was 1-2 mol / L, and the reaction voltage was 0.8-1.35 V vs. RHE.

5. The biomass electro-oxidation conversion reaction according to claim 3, characterized in that: The yields and selectivity of the target products 2,5-furan carboxylic acid and furfural were 95-99%.

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