d‐Band Center Engineering of BiVO 4 Photoanode for Boosting Bilateral Synergistic Interface Toward Efficient Photoelectrocatalytic CO 2 Reduction With BiCu Cathode

Photoelectrocatalytic (PEC) CO 2 reduction offers a sustainable route to address energy and environmental challenges. Herein, we designed a photoanode–cathode cooperative strategy by coupling d‐band center‐regulated BiVO 4 photoanodes (t/m‐BiVO 4 , m‐BiVO 4, and m‐BiVO 4 /Bi) with a BiCu cathode to elucidate bilateral synergy in PEC CO 2 reduction. Among the evaluated photoanodes, the m‐BiVO 4 /Bi delivers superior photoelectrochemical performance, achieving 98.84% Faradaic efficiency toward quantified liquid products, an applied‐bias photon‐to‐current efficiency of 1.67% at 0.6 V versus reversible hydrogen electrode (RHE), and a photocurrent density of 5.59 mA·cm −2 at 1.23 V versus RHE. More importantly, the CO 2 reduction pathways are tunable. In particular, the m‐BiVO 4 /Bi‖BiCu favors the C 2 pathway (HCOOH → C 2 H 5 OH) over −0.7 to −1.1 V versus RHE. The improved performance is attributed to an optimized photoanode electronic structure that facilitates hole injection to accelerate water‐oxidation kinetics, thereby supplying an optimal proton–electron flux to the cathode, boosting overall PEC activity, and creating favorable conditions conducive to C─C coupling. This work highlights photoanode electronic‐structure engineering as an effective lever to modulate the product selectivity and interfacial reaction dynamics in PEC CO 2 reduction.