Research progress and prospects of hydrogen fuel cell anode catalysts resistant to carbon monoxide poisoning

Hydrogen fuel cells are an efficient and clean energy technology that can directly convert the chemical energy of hydrogen into electrical energy. However, in practical applications, the anode catalysts of hydrogen fuel cells are easily poisoned by carbon monoxide (CO), resulting in performance degradation. CO usually comes from impurities in hydrogen or the fuel reforming process. Even trace amounts of CO can seriously reduce the activity of the catalyst. Therefore, the development of anode catalysts that are resistant to CO poisoning has become an important direction for hydrogen fuel cell research. This article will start from typical CO-resistant catalysts in acidic and alkaline electrolyte systems to explore the research progress of transition metal and oxide doping, catalyst surface structure regulation, and carrier regulation and selection.
1. Transition metal and oxide doping
Transition metal and oxide doping is a common method to improve the ability of catalysts to resist CO poisoning. By introducing other metals or oxides into the catalyst, the electronic structure of the catalyst can be changed, thereby weakening the binding force between CO and the catalyst surface.
Improvement of platinum-based catalysts: Platinum (Pt) is the most commonly used anode catalyst in hydrogen fuel cells, but it is very sensitive to CO. Researchers doped transition metals (such as ruthenium Ru, tin Sn, cobalt Co, etc.) into Pt to form alloy catalysts. These doped metals can change the electronic state of Pt and reduce the adsorption strength of CO, thereby improving the ability to resist CO poisoning.
Oxide doping: Introducing metal oxides (such as titanium dioxide TiO₂, tungsten oxide WO₃, etc.) into the catalyst is also an effective strategy. These oxides can promote the oxidation of CO through the "overflow effect" and convert it into non-toxic carbon dioxide (CO₂), thereby reducing the poisoning of CO to the catalyst.
2. Catalyst surface structure regulation
The surface structure of the catalyst has an important influence on its anti-CO poisoning performance. By regulating the surface morphology and crystal surface structure of the catalyst, its catalytic activity can be optimized.
Nanostructure design: Designing the catalyst into structures such as nanoparticles, nanowires or nanosheets can increase the number of active sites and improve the catalytic efficiency. For example, nanoporous structures can provide more reaction channels and promote the rapid oxidation of CO.
Crystal surface regulation: Different crystal surfaces have different adsorption capacities for CO. By regulating the exposed crystal surface of the catalyst, the adsorption strength of CO can be reduced. For example, the Pt(100) crystal surface has a stronger adsorption capacity for CO, while the Pt(111) crystal surface has a weaker adsorption capacity for CO. Therefore, optimizing the crystal surface exposure ratio is an effective way to improve the anti-CO poisoning performance.
3. Carrier Regulation and Selection
The carrier is not only the supporting material of the catalyst, but also can affect the performance of the catalyst through interaction. Selecting a suitable carrier and regulating it can significantly improve the catalyst's ability to resist CO poisoning.
Carbon-based carriers: Carbon materials (such as carbon black, carbon nanotubes, graphene, etc.) are commonly used catalyst carriers. They have high specific surface area and good conductivity, but their effect on resisting CO poisoning is limited. By introducing functional groups or doping heteroatoms (such as nitrogen N, boron B, etc.) on the carbon carrier, the interaction between the carrier and the catalyst can be enhanced and the stability of the catalyst can be improved.
Metal oxide carriers: Metal oxides (such as titanium dioxide TiO₂, cerium oxide CeO₂, etc.) can not only stabilize catalyst particles, but also promote the oxidation of CO through their own redox properties. For example, CeO₂ has excellent oxygen storage capacity and can oxidize CO to CO₂ at low potential.
Composite carriers: Composite different materials as carriers can combine their respective advantages. For example, a composite carrier of carbon materials and metal oxides can provide high conductivity and enhance the catalyst's ability to resist CO poisoning.
Research Prospects
In the future, the research on anti-CO poisoning catalysts will focus on the following aspects:
New catalyst design: Develop low-cost, high-efficiency non-precious metal catalysts (such as iron, cobalt, and nickel-based catalysts) to replace expensive platinum-based catalysts.
Multi-scale regulation: From atomic scale to nanoscale, comprehensively regulate the composition, structure, and surface properties of the catalyst to achieve higher anti-CO poisoning performance.
Smart carrier development: Design a carrier with responsive functions that can dynamically adjust the performance of the catalyst under different working conditions.
Practical application verification: Strengthen the combination of laboratory research and practical application to promote the commercialization of anti-CO poisoning catalysts.