d-Band Center Engineering of BiVO₄ Photoanode for Boosting Bilateral Synergistic Interface Toward Efficient...

Photoelectrocatalytic (PEC) CO₂ 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 BiVO₄ photoanodes (t/m-BiVO₄, m-BiVO_4, and m-BiVO₄/Bi) with a BiCu cathode to elucidate bilateral synergy in PEC CO₂ reduction. Among the evaluated photoanodes, the m-BiVO₄/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 CO₂ reduction pathways are tunable. In particular, the m-BiVO₄/Bi‖BiCu favors the C₂ pathway (HCOOH → C₂H₅OH) 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 CO₂ reduction.