Bias‐Free Solar‐Driven Syngas Production: A Fe2O3Photoanode Featuring Single‐Atom Cobalt Integrated with a Silver‐Palladium Cathode

Photoelectrochemical syngas production from aqueous CO2is a promising technique for carbon capture and utilization. Herein, we demonstrate the efficient and tunable syngas production by integrating a single‐atom cobalt‐catalyst‐decorated α‐Fe2O3photoanode with a bimetallic Ag/Pd alloy cathode. A record syngas production activity of 81.9 μmol cm−2 h−1(CO/H2ratio: ≈1 : 1) was achieved under artificial sunlight (AM 1.5 G) with an excellent durability. Systematic studies reveal that the Co single atoms effectively extract the holes from Fe2O3photoanodes and serve as active sites for promoting oxygen evolution. Simultaneously, the Pd and Ag atoms in bimetallic cathodes selectively adsorb CO2and protons for facilitating CO production. Further incorporation with a photovoltaic, to allow solar light (>600 nm) to be utilized, yields a bias‐free CO2reduction device with solar‐to‐CO and solar‐to‐H2conversion efficiencies up to 1.33 and 1.36 %, respectively.