Bimetal monatomic CeFe-N-C electrocatalyst and application thereof
By controlling the morphology of the CeFe-ZIF precursor and forming a CeFe-NC electrocatalyst at high temperature, the problems of harsh reaction conditions, dependence on precious metals, and insufficient activity in existing glycerol oxidation technologies have been solved, realizing the efficient electrocatalytic preparation of formic acid from glycerol, which has good prospects for industrial application.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ORDOS INST OF APPLIED TECH
- Filing Date
- 2026-01-15
- Publication Date
- 2026-04-14
AI Technical Summary
Existing glycerol oxidation technologies suffer from problems such as harsh reaction conditions, dependence on precious metals, insufficient activity, low selectivity, and uncontrollable structure. In particular, non-precious metal electrocatalysts perform poorly in the electrocatalytic oxidation of glycerol, making it difficult to achieve efficient preparation of formic acid.
By adjusting the content of surfactant PVP and the concentration of 2-methylimidazole, a CeFe-ZIF precursor was constructed and calcined at high temperature to form a regular dodecahedral CeFe-NC electrocatalyst. The synergistic effect of Ce and Fe single atoms on N-doped carbon support was utilized to achieve efficient electrocatalytic oxidation of glycerol.
High conversion of glycerol and selectivity of formic acid were achieved under mild conditions. The catalyst has a stable structure, low cost, is suitable for industrial application, and has the potential to be coupled with renewable energy.
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Figure CN121853019A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of new energy electrocatalysis and high-value utilization of biomass, and more specifically, to a bimetallic single-atom CeFe-NC electrocatalyst and its application. Background Technology
[0002] Glycerol is a highly enriched byproduct in biodiesel production. With the expansion of production scale, the inexpensive and surplus glycerol resources are difficult to utilize effectively. Selective oxidation of glycerol to formic acid is an important pathway for the high-value utilization of biomass. Formic acid is not only an important basic chemical raw material but is also considered a potential renewable liquid hydrogen storage carrier, possessing broad prospects for energy and chemical applications. Existing glycerol oxidation technologies include thermocatalytic oxidation, homogeneous oxidation, and biocatalysis, but the following problems still exist:
[0003] 1. The reaction conditions are harsh, often requiring high temperature, high pressure or strong oxidants, resulting in high energy consumption;
[0004] 2. Catalysts often rely on precious metals such as Pt and Pd, which are costly and prone to poisoning and deactivation;
[0005] 3. The glycerol oxidation pathway is complex, making it difficult to achieve high selectivity for formic acid;
[0006] 4. The activity and selectivity of non-precious metal catalysts are still insufficient.
[0007] 5. Electrocatalytic glycerol oxidation has attracted much attention due to its ability to proceed under mild conditions and its potential to be coupled with renewable energy sources. However, existing non-precious metal electrocatalysts still suffer from problems such as insufficient activity, limited selectivity, uncontrollable structure, and low exposure of active sites.
[0008] 6. Single-atom catalysts (SACs) have significant potential in the field of electrocatalysis due to their high metal utilization and tunable coordination environment. However, there are few reports on the synergistic construction of bimetallic single-atom structures using rare earth metals (such as Ce) and transition metals (such as Fe) for the electrocatalytic oxidation of glycerol, especially the construction of CeFe single-atom N-doped carbon catalysts with highly controllable morphology, which has been extensively studied in existing technologies.
[0009] Therefore, there is an urgent need to develop a single-atom electrocatalyst system with controllable structure, superior activity, high formic acid selectivity, good stability, and based on non-precious metals for the high-value electrocatalytic conversion of glycerol. Summary of the Invention
[0010] The purpose of this invention is to provide a bimetallic single-atom CeFe-NC electrocatalyst and its application. By adjusting the content of surfactant PVP and the concentration of 2-methylimidazole, the morphology of the ZIF precursor can be precisely controlled, and highly dispersed Ce and Fe single-atom sites are obtained during calcination. This catalyst exhibits high glycerol oxidation activity and formic acid selectivity under alkaline conditions.
[0011] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a bimetallic single-atom CeFe-NC electrocatalyst, wherein the electrocatalyst uses Ce and Fe single atoms supported on an N-doped carbon support as active centers to form a Ce–NC and Fe–NC coordination structure; the CeFe-NC electrocatalyst has a regular dodecahedral structure with a size of 30-50 nm.
[0012] The present invention is further configured such that the catalytic performance is optimal when the molar ratio of Ce to Fe in the CeFe-NC electrocatalyst is 1:1.
[0013] This invention further provides a method for preparing a bimetallic single-atom CeFe-NC electrocatalyst, comprising the following steps:
[0014] (1) Preparation of precursor solution: Cerium nitrate and ferric nitrate were dissolved in methanol solvent to obtain metal salt solution; surfactant PVP was added at a concentration of 0.3-1.5 g to regulate morphology and promote stable dispersion of metal atoms; 2-methylimidazole solution with a concentration of 0.01-0.09 M was prepared as organic ligand and N source;
[0015] (2) Construction of CeFe-ZIF precursor: 2-methylimidazole solution was added to a solution containing metal salt and PVP, and the reaction was carried out at room temperature with stirring to form a ZIF-like framework containing Ce and Fe; CeFe-ZIF precursor with dodecahedral morphology was obtained by centrifugation, washing and drying.
[0016] (3) High-temperature calcination to form single-atom sites: Under the protection of inert nitrogen gas, the precursor is heated to 900 °C and calcined; during the calcination process, the organic ligands are carbonized to form N-doped carbon structure, and Ce and Fe single atoms are stably anchored; CeFe-NC electrocatalyst with dodecahedral morphology and highly dispersed metal sites is obtained.
[0017] The present invention further provides an application of a bimetallic single-atom CeFe-NC electrocatalyst in the electrocatalytic oxidation of glycerol to formic acid.
[0018] The present invention is further configured as follows:
[0019] The procedure for electrocatalytic oxidation of glycerol using the CeFe-NC electrocatalyst is as follows:
[0020] The working electrode was prepared on carbon paper; 0.1 M glycerol + 1.0 M KOH solution was used as the electrolyte; glycerol electrocatalytic oxidation was carried out under the conditions of 1.62 V, 60 °C and 4 h.
[0021] In summary, the present invention has the following beneficial effects:
[0022] 1. Significantly enhanced activity
[0023] CeNC-based catalysts showed near-zero glycerol conversion, while CeFe-NC catalysts achieved approximately 67% glycerol conversion under the same conditions, indicating that the introduction of Fe significantly improved the electronic structure and promoted the glycerol oxidation pathway.
[0024] 2. Formic acid has high selectivity.
[0025] Under optimized conditions, high formic acid yields can be obtained with a significant reduction in byproduct formation, demonstrating excellent directional C / C bond breaking ability.
[0026] 3. PVP / 2-methylimidazole enables precise structural regulation.
[0027] The dodecahedral structure is regular and the size is uniform; it remains structurally stable after calcination and has a high exposure of active sites; thus achieving a high structure-performance correlation.
[0028] 4. Significant synergistic effect of single-atom active sites
[0029] The synergistic effect of Ce-Nx and Fe-Nx enhances glycerol adsorption and intermediate conversion; the high dispersion of metal atoms results in high utilization rate and catalytic efficiency superior to that of nanoparticle structures.
[0030] 5. Good catalytic stability
[0031] The catalyst exhibits high performance retention and no significant structural collapse during cyclic testing, demonstrating its excellent durability.
[0032] 6. Non-precious metal system, low cost, and scalable preparation.
[0033] Replacing Pt / Pd with Ce and Fe reduces material costs and makes industrial applications possible.
[0034] 7. The process is green and mild, and can be coupled with other electrochemical processes.
[0035] The reaction is carried out at medium and low temperatures (about 60 °C) and normal pressure, without the need for highly toxic or corrosive oxidants, making the process green and environmentally friendly. It can be coupled with reactions such as hydrogen evolution at the cathode to achieve simultaneous hydrogen production and formic acid preparation, and has the potential advantage of synergistic production of energy and chemicals.
[0036] In summary, this invention, through the rational design of CeFe bimetallic single-atom sites and their N-doped carbon support structure, combined with the synergistic regulation of PVP and 2-methylimidazole, has achieved a glycerol electrocatalytic oxidation formic acid production system with controllable structure, excellent performance, and moderate cost. It effectively overcomes the problems of insufficient catalytic activity, low formic acid selectivity, and dependence on precious metals in the prior art, and has good prospects for promotion and application. Attached Figure Description
[0037] Figure 1 This is a schematic diagram of the process flow for preparing the CeFe-NC catalyst of the present invention;
[0038] Figure 2 SEM images of CeFe-ZIF precursors under different PVP dosages and 2-methylimidazole concentrations show the dodecahedral morphology and size variations.
[0039] Figure 3 The image shows a TEM image of the calcined CeFe-NC catalyst, illustrating its dodecahedral morphology.
[0040] Figure 4 A comparison of the current density-time curves and bar charts of glycerol conversion and formic acid yield of CeNC and the CeFe-NC catalyst of this invention in the electrocatalytic oxidation of glycerol;
[0041] Figure 5 Comparative curves or bar charts showing the effects of different PVP dosages, different Ce:Fe ratios, and different electrolysis conditions (potential, temperature) on the electrocatalytic oxidation performance of glycerol;
[0042] Figure 6 The graph shows the cycle stability test results of the CeFe-NC catalyst of this invention.
[0043] Figure 7 A schematic diagram of a possible reaction mechanism for the electrocatalytic oxidation of glycerol to formic acid on the surface of a CeFe-NC catalyst. Detailed Implementation
[0044] The following is in conjunction with the appendix Figure 1-7 The present invention will be described in further detail below.
[0045] Example 1: A method for preparing a bimetallic single-atom CeFe-NC electrocatalyst
[0046] The preparation method of the bimetallic single-atom CeFe-NC electrocatalyst includes the following steps:
[0047] (1) Preparation of precursor solution: Cerium nitrate and ferric nitrate were dissolved in methanol solvent to obtain metal salt solution; surfactant PVP was added at a rate of 0.3 g to regulate morphology and promote stable dispersion of metal atoms; 2-methylimidazole solution with a concentration of 0.09 M was prepared as organic ligand and N source.
[0048] (2) Construction of CeFe-ZIF precursor: 2-methylimidazole solution was added to a solution containing metal salt and PVP, and the reaction was carried out at room temperature with stirring to form a ZIF-like framework containing Ce and Fe; CeFe-ZIF precursor with dodecahedral morphology was obtained by centrifugation, washing and drying.
[0049] (3) High-temperature calcination to form single-atom sites: Under the protection of inert nitrogen gas, the precursor is heated to 900 °C and calcined; during the calcination process, the organic ligands are carbonized to form N-doped carbon structure, and Ce and Fe single atoms are stably anchored; CeFe-NC electrocatalyst with dodecahedral morphology and highly dispersed metal sites is obtained.
[0050] Example 2: A method for preparing a bimetallic single-atom CeFe-NC electrocatalyst
[0051] The preparation method of the bimetallic single-atom CeFe-NC electrocatalyst includes the following steps:
[0052] (1) Preparation of precursor solution: Cerium nitrate and ferric nitrate were dissolved in methanol solvent to obtain metal salt solution; surfactant PVP was added at a rate of 0.6 g to regulate morphology and promote stable dispersion of metal atoms; 2-methylimidazole solution with a concentration of 0.09 M was prepared as organic ligand and N source.
[0053] (2) Construction of CeFe-ZIF precursor: 2-methylimidazole solution was added to a solution containing metal salt and PVP, and the reaction was carried out at room temperature with stirring to form a ZIF-like framework containing Ce and Fe; CeFe-ZIF precursor with dodecahedral morphology was obtained by centrifugation, washing and drying.
[0054] (3) High-temperature calcination to form single-atom sites: Under the protection of inert nitrogen gas, the precursor is heated to 900 °C and calcined; during the calcination process, the organic ligands are carbonized to form N-doped carbon structure, and Ce and Fe single atoms are stably anchored; CeFe-NC electrocatalyst with dodecahedral morphology and highly dispersed metal sites is obtained.
[0055] Example 3: A method for preparing a bimetallic single-atom CeFe-NC electrocatalyst
[0056] The preparation method of the bimetallic single-atom CeFe-NC electrocatalyst includes the following steps:
[0057] (1) Preparation of precursor solution: Cerium nitrate and ferric nitrate were dissolved in methanol solvent to obtain metal salt solution; surfactant PVP was added at a rate of 0.9 g to regulate morphology and promote stable dispersion of metal atoms; 2-methylimidazole solution with a concentration of 0.09 M was prepared as organic ligand and N source.
[0058] (2) Construction of CeFe-ZIF precursor: 2-methylimidazole solution was added to a solution containing metal salt and PVP, and the reaction was carried out at room temperature with stirring to form a ZIF-like framework containing Ce and Fe; CeFe-ZIF precursor with dodecahedral morphology was obtained by centrifugation, washing and drying.
[0059] (3) High-temperature calcination to form single-atom sites: Under the protection of inert nitrogen gas, the precursor is heated to 900 °C and calcined; during the calcination process, the organic ligands are carbonized to form N-doped carbon structure, and Ce and Fe single atoms are stably anchored; CeFe-NC electrocatalyst with dodecahedral morphology and highly dispersed metal sites is obtained.
[0060] Example 4: A method for preparing a bimetallic single-atom CeFe-NC electrocatalyst
[0061] The preparation method of the bimetallic single-atom CeFe-NC electrocatalyst includes the following steps:
[0062] (1) Preparation of precursor solution: Cerium nitrate and ferric nitrate were dissolved in methanol solvent to obtain metal salt solution; surfactant PVP was added at a concentration of 1.2 g to regulate morphology and promote stable dispersion of metal atoms; 2-methylimidazole solution with a concentration of 0.09 M was prepared as organic ligand and N source.
[0063] (2) Construction of CeFe-ZIF precursor: 2-methylimidazole solution was added to a solution containing metal salt and PVP, and the reaction was carried out at room temperature with stirring to form a ZIF-like framework containing Ce and Fe; CeFe-ZIF precursor with dodecahedral morphology was obtained by centrifugation, washing and drying.
[0064] (3) High-temperature calcination to form single-atom sites: Under the protection of inert nitrogen gas, the precursor is heated to 900 °C and calcined; during the calcination process, the organic ligands are carbonized to form N-doped carbon structure, and Ce and Fe single atoms are stably anchored; CeFe-NC electrocatalyst with dodecahedral morphology and highly dispersed metal sites is obtained.
[0065] Example 5: A method for preparing a bimetallic single-atom CeFe-NC electrocatalyst
[0066] The preparation method of the bimetallic single-atom CeFe-NC electrocatalyst includes the following steps:
[0067] (1) Preparation of precursor solution: Cerium nitrate and ferric nitrate were dissolved in methanol solvent to obtain metal salt solution; surfactant PVP was added at a rate of 1.5 g to regulate morphology and promote stable dispersion of metal atoms; 2-methylimidazole solution with a concentration of 0.09 M was prepared as organic ligand and N source.
[0068] (2) Construction of CeFe-ZIF precursor: 2-methylimidazole solution was added to a solution containing metal salt and PVP, and the reaction was carried out at room temperature with stirring to form a ZIF-like framework containing Ce and Fe; CeFe-ZIF precursor with dodecahedral morphology was obtained by centrifugation, washing and drying.
[0069] (3) High-temperature calcination to form single-atom sites: Under the protection of inert nitrogen gas, the precursor is heated to 900 °C and calcined; during the calcination process, the organic ligands are carbonized to form N-doped carbon structure, and Ce and Fe single atoms are stably anchored; CeFe-NC electrocatalyst with dodecahedral morphology and highly dispersed metal sites is obtained.
[0070] Example 6: Structural characterization of the CeFe-NC electrocatalyst synthesized in Example 1
[0071] like Figure 2 As shown, the CeFe-NC electrocatalyst synthesized in Example 1 was characterized by scanning electron microscopy. The test results showed that the synthesized CeFe-NC catalyst had a typical dodecahedral structure and the prepared catalyst had a uniform morphology.
[0072] Application Example 1: Electrocatalytic oxidation of glycerol using the CeFe-NC electrocatalyst synthesized in Example 1.
[0073] Preparation of working electrode: Weigh 5 mg CeFe-NC electrocatalyst and add it to 1.0 ml Nafion + isopropanol solution. Sonicate for 30 min to obtain catalyst ink. Coat the ink onto 1.5*2.0 cm carbon paper and use it as the working electrode.
[0074] The prepared CeFe-NC electrocatalyst was subjected to electrocatalytic oxidation of glycerol: 10 ml of 0.1 M glycerol + 1.0 M KOH solution was measured, and the carbon paper coated with the catalyst was used as the working electrode, mercury / mercuric oxide as the reference electrode, and platinum wire as the counter electrode. The reaction was carried out at 1.62 V (vs. RHE) and 60 °C for 4 h.
[0075] This application example corresponds to the appendix. Figure 4 As shown by the red line in Figure a, after 4 hours of reaction, the conversion rate of glycerol can reach 67.6%, and the formic acid yield can reach 55.2%, which is significantly higher than the electro-oxidation performance of glycerol by CeNC catalyst (both glycerol conversion rate and formic acid yield are 0%).
[0076] Comparative Example 1: Electrocatalytic oxidation of glycerol using CeNC
[0077] Preparation of working electrode: Weigh 5 mg of CeNC electrocatalyst and add it to 1.0 ml of Nafion + isopropanol solution. Sonicate for 30 min to obtain catalyst ink. Coat the ink onto 1.5*2.0 cm carbon paper and use it as the working electrode.
[0078] The prepared CeNC electrocatalyst was subjected to electrocatalytic oxidation of glycerol: 10 ml of 0.1 M glycerol + 1.0 M KOH solution was measured, and the carbon paper coated with the catalyst was used as the working electrode, mercury / mercuric oxide as the reference electrode, and platinum wire as the counter electrode. The reaction was carried out at 1.62 V (vs. RHE) and 60 °C for 4 h.
[0079] This application example corresponds to the appendix. Figure 4 The black line in graph a indicates that after 4 hours of reaction, the conversion rate of glycerol was 0% and the formic acid yield was 0%, significantly lower than the glycerol electrooxidation performance of the CeFe-NC electrocatalyst (glycerol conversion rate 67.6%, formic acid yield 55.2%). This demonstrates that the introduction of Fe can significantly improve the catalytic performance of glycerol electrooxidation.
[0080] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.
Claims
1. A bimetallic single-atom CeFe-NC electrocatalyst, characterized in that: The electrocatalyst uses Ce and Fe single atoms supported on an N-doped carbon support as active centers to form a Ce–NC and Fe–NC coordination structure; the CeFe-NC electrocatalyst has a regular dodecahedral structure with a size of 30-50 nm.
2. The bimetallic single-atom CeFe-NC electrocatalyst according to claim 1, characterized in that: The CeFe-NC electrocatalyst exhibits optimal catalytic performance when the molar ratio of Ce to Fe is 1:
1.
3. The method for preparing a bimetallic single-atom CeFe-NC electrocatalyst according to claim 1, characterized in that: Includes the following steps: (1) Preparation of precursor solution: Cerium nitrate and ferric nitrate are dissolved in methanol solvent to obtain metal salt solution; The surfactant PVP was added at a concentration of 0.3-1.5 g to regulate morphology and promote stable dispersion of metal atoms; a 0.01-0.09 M 2-methylimidazole solution was prepared as an organic ligand and nitrogen source. (2) Construction of CeFe-ZIF precursor: 2-methylimidazole solution was added to a solution containing metal salt and PVP, and the reaction was carried out at room temperature with stirring to form a ZIF-like framework containing Ce and Fe; CeFe-ZIF precursor with dodecahedral morphology was obtained by centrifugation, washing and drying. (3) High-temperature calcination to form single-atom sites: Under the protection of inert nitrogen gas, the precursor is heated to 900 °C and calcined; during the calcination process, the organic ligands are carbonized to form N-doped carbon structure, and Ce and Fe single atoms are stably anchored; CeFe-NC electrocatalyst with dodecahedral morphology and highly dispersed metal sites is obtained.
4. The application of the bimetallic single-atom CeFe-NC electrocatalyst according to claim 1 in the electrocatalytic oxidation of glycerol to formic acid.
5. The application according to claim 4, characterized in that: The procedure for electrocatalytic oxidation of glycerol using the CeFe-NC electrocatalyst is as follows: The working electrode was prepared on carbon paper; 0.1 M glycerol + 1.0 M KOH solution was used as the electrolyte; glycerol electrocatalytic oxidation was carried out at 1.62 V, 60 °C and 4 h.