A Ni-doped lignin-based mesoporous carbon material and its application in fuel cells
By using solvent evaporation-induced self-assembly and in-situ nickel doping, Ni-doped lignin-based mesoporous carbon materials with highly dispersed Ni active sites were prepared. This solved the problem of insufficient activity and stability of existing lignin-based carbon materials in the oxygen reduction reaction of fuel cells, and enabled a high-efficiency, low-cost fuel cell catalyst to replace commercial platinum-based catalysts.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- LIAONING UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2026-03-09
- Publication Date
- 2026-06-02
Smart Images
Figure CN122136379A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of carbon-based electrocatalytic materials technology, specifically relating to a Ni-doped lignin-based mesoporous carbon material and its application in fuel cells, particularly suitable as a non-precious metal electrocatalytic material for the oxygen reduction reaction in fuel cells. Background Technology
[0002] Fuel cells, as efficient and clean electrochemical energy conversion devices, have broad application prospects in new energy vehicles, distributed power generation, and portable power supplies. The oxygen reduction reaction (ORR) is the core reaction at the cathode of a fuel cell, characterized by slow reaction kinetics, high overpotential, and high catalyst dependence. Currently, commercially available catalysts are mainly platinum-based precious metals, but their scarcity, high cost, poor stability, and poor methanol resistance severely restrict the large-scale industrial application of fuel cells. Therefore, developing low-cost, highly active, and highly stable non-precious metal oxygen reduction catalysts has become a key research focus in the field of energy materials.
[0003] Lignin is the most abundant natural aromatic polymer compound found in agricultural and forestry biomass waste. It boasts advantages such as high carbon content, wide availability, renewability, and low cost, making it an ideal green carbon source for preparing carbon-based catalytic materials. Mesoporous carbon materials possess characteristics such as large specific surface area, regular pore structure, good electrical conductivity, and tunable structure, effectively enhancing the exposure of active sites and accelerating mass transport and electron transfer rates, demonstrating great potential in the field of electrocatalysis. However, existing lignin-based carbon materials generally suffer from problems such as disordered pore structure, poor dispersion of active sites, easy aggregation of doped metals, and insufficient oxygen reduction catalytic activity and stability. Furthermore, most are only applied to traditional fields such as adsorption and organic catalysis. Technologies for the in-situ doping of lignin-based mesoporous carbon with metals for the targeted application of oxygen reduction electrocatalysis in fuel cells remain relatively scarce.
[0004] To address the aforementioned issues, this invention employs a solvent evaporation-induced self-assembly combined with an in-situ nickel doping strategy to prepare lignin-based carbon materials with highly dispersed Ni active sites and a highly mesoporous structure. This significantly enhances their oxygen reduction electrocatalytic performance, providing a novel technical solution for developing high-performance, low-cost non-precious metal catalysts for fuel cells. Summary of the Invention
[0005] To overcome the shortcomings of existing technologies, this invention aims to provide a Ni-doped lignin-based mesoporous carbon material. This material uses renewable lignin as a carbon source, has regular pores and uniformly dispersed metal sites, and exhibits excellent oxygen reduction electrocatalytic performance and stability. It can be used as a highly efficient non-precious metal catalyst in fuel cells.
[0006] Another objective of this invention is to provide a method for preparing the above-mentioned Ni-doped lignin-based mesoporous carbon material, which combines solvent evaporation-induced self-assembly with in-situ metal doping to achieve precise control of material structure and active sites. The process is simple, the conditions are mild, and it is easy to scale up.
[0007] Another object of the present invention is to provide the application of the above-mentioned Ni-doped lignin-based mesoporous carbon material in fuel cells, especially exhibiting high catalytic activity, high selectivity and excellent cycle stability in the oxygen reduction reaction, which can replace commercial platinum-based catalysts.
[0008] To achieve the above objectives, the present invention adopts the following technical solution: A Ni-doped lignin-based mesoporous carbon material is prepared by in-situ doping of Ni ions, followed by solvent evaporation self-assembly, cross-linking curing, and high-temperature calcination, using lignin as the carbon source, aromatic phenols as modifiers, and a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer as a soft template. The material has a mesoporous structure and highly dispersed Ni active sites, with a Ni loading of 1 wt% to 10 wt% and a pore size distribution of 2 nm to 5 nm, and can be used for oxygen reduction electrocatalysis in fuel cells.
[0009] The above-mentioned method for preparing Ni-doped lignin-based mesoporous carbon materials includes the following steps: (1) dissolving lignin and aromatic phenolic compounds in an organic solvent at a mass ratio of 1:0.2 to 1:2 and stirring until uniform to obtain an organic precursor solution; (2) adding a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer solution to the precursor solution and stirring to form micelles; (3) adding a soluble nickel salt to the micelle system to obtain a metal-organic composite system with uniformly dispersed Ni ions; (4) adding an aldehyde crosslinking agent and mixing until uniform, and then performing solvent evaporation and thermal crosslinking curing in sequence; (5) calcining at a high temperature of 600℃ to 900℃ for 2 h to 4 h under an inert atmosphere to obtain Ni-doped lignin-based mesoporous carbon materials.
[0010] The soluble nickel salt is at least one of nickel nitrate, nickel acetate, and nickel chloride, and the mass ratio of nickel salt to lignin is 0.01 to 0.1:1; the thermal crosslinking curing temperature is 100℃ to 180℃, and the curing time is 2 h to 6 h.
[0011] The Ni-doped lignin-based mesoporous carbon material prepared by this invention can be used as a non-precious metal oxygen reduction catalyst for proton exchange membrane fuel cells or alkaline fuel cells. Under alkaline conditions of 0.1 M KOH, its oxygen reduction onset potential is 0.82 V to 0.95 V (vs. RHE), its half-wave potential is 0.75 V to 0.88 V (vs. RHE), and its limiting diffusion current density is 4.5 mA·cm⁻² to 6.0 mA·cm⁻², showing good prospects for industrial application.
[0012] This invention focuses on solvent evaporation-induced self-assembly and in-situ nickel coordination. Lignin, aromatic phenols, and triblock copolymers self-assemble into micelles through hydrogen bonding and hydrophobic interactions. Nickel ions coordinate with and are highly dispersed in the organic precursor. After cross-linking, curing, and high-temperature calcination, the template is removed, forming a 2–5 nm mesoporous structure. Nickel is transformed in situ into highly dispersed active sites, while the carbon framework is simultaneously carbonized and its conductivity is improved. During catalysis, the mesopores accelerate mass transfer, the highly dispersed Ni sites provide efficient oxygen reduction active centers, and the conductive carbon matrix ensures rapid electron transport. These three factors synergistically achieve excellent oxygen reduction electrocatalytic performance in fuel cells.
[0013] 1. Using renewable lignin as a carbon source, it is widely available, environmentally friendly, and inexpensive, effectively realizing the high-value utilization of agricultural and forestry waste.
[0014] 2. Mesoporous structures are prepared by solvent evaporation-induced self-assembly, resulting in uniform pore size and large specific surface area, which significantly improves the mass transfer efficiency of electrolyte and oxygen and exposes more active sites.
[0015] 3. In-situ Ni doping is adopted, which results in high metal dispersion and strong bonding, avoids metal agglomeration, and greatly improves oxygen reduction catalytic activity and stability.
[0016] 4. The preparation process is simple and controllable, the conditions are mild, no complex equipment is required, and it is suitable for large-scale production.
[0017] 5. As a non-precious metal catalyst, it exhibits excellent oxygen reduction performance under alkaline conditions, and can replace commercial platinum-based catalysts, significantly reducing the cost of fuel cells. Attached Figure Description
[0018] Figure 1 This is a transmission electron microscope (TEM) image of the Ni-doped lignin-based mesoporous carbon material prepared according to the present invention.
[0019] Figure 2 This is a comparison chart of the onset potential test results for different Ni loadings.
[0020] Figure 3 A comparison chart of half-wave potential test results for different Ni loadings.
[0021] Figure 4 A comparison of the test results of the limiting diffusion current density for different Ni loadings. Detailed Implementation
[0022] The present invention will be described in detail below with reference to the embodiments.
[0023] Example 1
[0024] Lignin and phenol were dissolved in ethanol at a mass ratio of 1:0.5 and stirred until homogeneous to obtain an organic precursor solution. A polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer was added, and stirring continued to form micelles. Nickel nitrate was added at a nickel salt to lignin mass ratio of 0.03:1, and stirred until uniformly dispersed. Formaldehyde was added as a crosslinking agent, and after thorough mixing, solvent evaporation self-assembly was performed, followed by thermal crosslinking at 120 °C for 4 h. The mixture was then calcined at 750 °C for 3 h under a nitrogen atmosphere to obtain Ni-doped lignin-based mesoporous carbon material.
[0025] The resulting material has a Ni loading of 3 wt% and a pore size of approximately 3.2 nm. In 0.1 M KOH, the oxygen reduction initiation potential is 0.86 V (vs. RHE), the half-wave potential is 0.79 V (vs. RHE), and the limiting diffusion current density is 4.8 mA・cm⁻².
[0026] Example 2
[0027] Lignin and resorcinol were dissolved in ethanol at a mass ratio of 1:1. After stirring and dissolving, a triblock copolymer was added to form micelles. Nickel acetate was added at a nickel salt to lignin mass ratio of 0.05:1, followed by crosslinking with glutaraldehyde. After solvent evaporation, crosslinking was performed at 150 °C for 3 h, followed by calcination at 800 °C for 2 h under nitrogen atmosphere.
[0028] The resulting material has a Ni loading of 5 wt% and a pore size of approximately 3.8 nm. In 0.1 M KOH, the oxygen reduction initiation potential is 0.91 V (vs. RHE), the half-wave potential is 0.84 V (vs. RHE), and the limiting diffusion current density is 5.6 mA・cm⁻².
[0029] Example 3
[0030] Lignin and cresol were dissolved in ethanol at a mass ratio of 1:0.8, and a triblock copolymer was added for self-assembly. Nickel chloride was added at a nickel salt to lignin mass ratio of 0.08:1, and formaldehyde was used for crosslinking. The mixture was cured at 160 °C for 5 h and calcined at 850 °C for 2.5 h under a nitrogen atmosphere.
[0031] The resulting material has an 8 wt% Ni loading and a pore size of approximately 4.0 nm. In 0.1 M KOH, the oxygen reduction initiation potential is 0.95 V (vs. RHE), the half-wave potential is 0.88 V (vs. RHE), and the limiting diffusion current density is 6.2 mA・cm⁻².
[0032] Comparative Example 1
[0033] Lignin and phenol were dissolved in ethanol at a mass ratio of 1:0.5 and stirred until homogeneous to obtain an organic precursor solution. A polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer was added, and stirring continued to form micelles. Formaldehyde was added directly as a crosslinking agent without adding any nickel salt, and after homogeneous mixing, solvent evaporation self-assembly was performed, followed by thermal crosslinking at 120 °C for 4 h. The mixture was then calcined at 750 °C for 3 h under a nitrogen atmosphere to obtain an undoped Ni-based mesoporous carbon material. Performance tests showed that under alkaline conditions of 0.1 M KOH, the oxygen reduction onset potential of this comparative material was only 0.72 V (vs. RHE), the half-wave potential was 0.65 V (vs. RHE), and the limiting diffusion current density was only 2.8 mA・cm⁻², indicating catalytic performance far lower than that of the embodiments of this invention.
Claims
1. A Ni-doped lignin-based mesoporous carbon material, characterized in that, Using lignin as a carbon source, aromatic phenols as modifiers, and a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer as a soft template, the material was prepared by in-situ doping with Ni ions followed by solvent evaporation self-assembly, cross-linking curing, and high-temperature calcination. The material has a mesoporous structure and highly dispersed Ni active sites, with a Ni loading of 1 wt% to 10 wt% and a pore size distribution of 2 nm to 5 nm. It is applied to oxygen reduction electrocatalysis in fuel cells.
2. A method for preparing Ni-doped lignin mesoporous carbon material, characterized in that, The process includes the following steps: (1) dissolving lignin and aromatic phenolic compounds in an organic solvent at a mass ratio of 1:0.2 to 1:2 and stirring until homogeneous to obtain an organic precursor solution; (2) adding a polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer solution to the precursor solution and stirring to form micelles; (3) adding a soluble nickel salt to the micelle system to obtain a metal-organic composite system with uniformly dispersed Ni ions; (4) adding an aldehyde crosslinking agent and mixing until homogeneous, followed by solvent evaporation and thermal crosslinking curing; (5) calcining at a high temperature of 600℃ to 900℃ for 2 h to 4 h under an inert atmosphere to obtain Ni-doped lignin mesoporous carbon material.
3. The preparation method according to claim 2, characterized in that, The soluble nickel salt is at least one of nickel nitrate, nickel acetate, and nickel chloride, and the mass ratio of the nickel salt to lignin is 0.01 to 0.1:
1.
4. The preparation method according to claim 2, characterized in that, The thermal crosslinking curing temperature is 100℃~180℃, and the curing time is 2 h~6 h.
5. The application of the Ni-doped lignin-based mesoporous carbon material according to claim 1, characterized in that, It is a non-precious metal oxygen reduction catalyst used in proton exchange membrane fuel cells or alkaline fuel cells; under 0.1 M KOH alkaline conditions, its oxygen reduction onset potential is 0.82 V to 0.95 V (vs. RHE), its half-wave potential is 0.75 V to 0.88 V (vs. RHE), and its limiting diffusion current density is 4.5 mA・cm⁻² to 6.0 mA・cm⁻².