Research Progress and Perspectives on Anti-Poisoning Hydrogen Oxidation Reaction Electrocatalysts for Hydrogen Fuel Cells

As global demand for clean and sustainable energy continues to rise, fuel cell technology has seen rapid advancement. However, the presence of trace impurities like carbon monoxide (CO) and hydrogen sulfide (H₂S) in hydrogen fuel can significantly deactivate the anode by blocking its active sites, leading to reduced performance. Developing electrocatalysts that are resistant to CO and H₂S poisoning has therefore become a critical priority. This paper provides a comprehensive analysis of the poisoning mechanisms of CO and H₂S and reviews the key strategies developed over the past few decades to enhance the impurity tolerance of anode electrocatalysts. It begins by examining the differences in hydrogen oxidation reaction (HOR) mechanisms in acidic and alkaline environments, focusing on the roles of hydrogen binding energy (HBE) and hydroxide binding energy (OHBE). Next, it outlines three main approaches to mitigate CO poisoning: (I) bifunctional mechanisms, (II) direct mechanisms, and (III) constructing protective blocking layers. The review then shifts to strategies for countering H₂S poisoning, emphasizing both electrocatalyst design and structural improvements in fuel cells. Finally, the paper highlights recent advances in anti-poisoning electrocatalysts, discusses their applications and limitations, and identifies the key challenges and future opportunities for further research in this field.