Electrothermal Water‐Gas Shift Reaction at Room Temperature with a Silicomolybdate‐Based Palladium Single‐Atom Catalyst

Abstract

AbstractThe water‐gas shift (WGS) reaction is often conducted at elevated temperature and requires energy‐intensive separation of hydrogen (H2) from methane (CH4), carbon dioxide (CO2), and residual carbon monoxide (CO). Designing processes to decouple CO oxidation and H2 production provides an alternative strategy to obtain high‐purity H2 streams. We report an electrothermal WGS process combining thermal oxidation of CO on a silicomolybdic acid (SMA)‐supported Pd single‐atom catalyst (Pd1/CsSMA) and electrocatalytic H2 evolution. The two half‐reactions are coupled through phosphomolybdic acid (PMA) as a redox mediator at a moderate anodic potential of 0.6 V (versus Ag/AgCl). Under optimized conditions, our catalyst exhibited a TOF of 1.2 s−1 with turnover numbers above 40 000 mol  molPd−1 achieving stable H2 production with a purity consistently exceeding 99.99 %.