Direct Methanol Fuel Cell with Porous Carbon-Supported PtRu Single-Atom Catalysts for Coproduction of Electricity and Value-Added Formate

Bottlenecks in direct methanol fuel cells (DMFCs) with conventional noble metals as anode catalysts involve the formation of valueless byproducts and carbon dioxide (CO2) emissions. Carbon-supported Pt single atoms have demonstrated high performance in DMFCs. However, the adsorbed intermediates (COads) strongly bind to Pt single-atom sites, resulting in complete methanol oxidation to CO2 and low power densities. Herein, we have developed a DMFC for CO2-emission-free coproduction of electricity and valuable formate using metal organic framework (MOF)-derived N-doped porous carbon-supported PtRu single-atom (referred to as PtRuSA/NPC) catalysts. The DMFC produces current and power densities of 657 mA cm–2 and 97.4 mW cm–2, respectively, at a potential of 0.65 V with a 98.4% Faraday efficiency for formate at 80 °C. Density functional theory (DFT) calculations show that CH3OH molecules preferentially adsorb onto the PtRu single atoms, but their oxidation to CO2 molecules on PtRuSA/NPC is kinetically unfavorable due to the large energy barrier. This study offers a pathway to developing high-performance and CO2-emission-free electrocatalysts for DMFCs.