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

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Photoelectrocatalytic (PEC) CO2 reduction is a promising sustainable technology for energy and environmental challenges.
• Developing efficient photoanode-cathode systems is crucial for improving PEC CO2 reduction performance and selectivity.

Purpose of the Study:

• To design a cooperative photoanode-cathode strategy for enhanced PEC CO2 reduction.
• To investigate the effect of d-band center-regulated BiVO4 photoanodes coupled with a BiCu cathode on PEC performance and product selectivity.
• To elucidate the bilateral synergy between photoanode and cathode in the PEC CO2 reduction process.

Main Methods:

• Fabrication of d-band center-regulated BiVO4 photoanodes (t/m-BiVO4, m-BiVO4, and m-BiVO4/Bi).
• Coupling of BiVO4 photoanodes with a BiCu cathode for PEC CO2 reduction experiments.
• Characterization of photoelectrochemical performance, including Faradaic efficiency, applied-bias photon-to-current efficiency (APIBE), and photocurrent density.
• Analysis of CO2 reduction pathways and product selectivity.

Main Results:

• The m-BiVO4/Bi photoanode coupled with the BiCu cathode exhibited superior photoelectrochemical performance.
• Achieved 98.84% Faradaic efficiency for liquid products, 1.67% APIBE at 0.6 V vs RHE, and 5.59 mA·cm-2 photocurrent density at 1.23 V vs RHE.
• Demonstrated tunable CO2 reduction pathways, favoring the C2 pathway (e.g., ethanol production) at specific potentials (-0.7 to -1.1 V vs RHE).

Conclusions:

• Optimized photoanode electronic structure facilitates hole injection and water oxidation, boosting overall PEC activity.
• The cooperative strategy enhances proton-electron flux to the cathode, promoting C-C coupling for C2 product formation.
• Photoanode electronic structure engineering is an effective approach to modulate product selectivity and interfacial dynamics in PEC CO2 reduction.