What formate electro-oxidation can teach us about CO poisoning on Pt during biomass oxidation

Catalyst deactivation due to *CO poisoning is a persistent challenge in the electrochemical oxidation of biomass-derived molecules such as glycerol and glucose. On platinum catalysts, *CO forms readily as a reaction intermediate, blocking active sites and requiring high overpotentials for removal—often leading to undesired overoxidation of valuable products. Understanding the fundamental origins of *CO formation is thus critical for designing more selective and stable catalysts. Since biomass oxidation can be extremely complex and involve a multitude of adsorbates and products, here we use a simplified model system, formate oxidation, to investigate *CO formation on Pt in alkaline pH . Starting from operando surface-enhanced infrared spectroscopy, we show that the adsorption configuration of formate determines if the surface will be poisoned by *CO. Oxygen-bound formate (*OOCH) undergoes direct and stable oxidation to CO₂, while carbon-bound formate (*COOH) disproportionates to form *CO–*OH, initiating poisoning. These insights offer a mechanistic foundation for designing Pt-based catalysts that resist *CO formation by selectively stabilizing *OOCH over *COOH intermediates, with broader implications for improving biomass electrooxidation performance.