Enhancing photoelectrochemical water splitting by combining work function tuning and heterojunction engineering

Area of Science:

• Materials Science
• Renewable Energy
• Photocatalysis

Background:

• Photoelectrochemical (PEC) water splitting is crucial for sustainable hydrogen production.
• Bismuth vanadate (BiVO4) is a promising photoanode material, but suffers from limitations like interfacial energy loss and poor charge separation.
• Optimizing semiconductor interfaces is key to improving PEC performance.

Purpose of the Study:

• To enhance the efficiency of PEC water splitting using novel doping and heterojunction strategies.
• To investigate the synergistic effects of molybdenum (Mo) doping in BiVO4 and boron (B) doping in carbon nitride (C3N4).
• To reduce interfacial energy loss and improve charge carrier dynamics in BiVO4-based photoanodes.

Main Methods:

• Work function adjustment of BiVO4 via Mo doping to minimize interfacial energy loss.
• Formation of a B-C3N4/Mo-BiVO4 heterojunction to facilitate directional charge transfer.
• Optimization of doping concentrations and heterojunction interfaces for enhanced performance.

Main Results:

• Mo doping in BiVO4 significantly reduced open-circuit potential losses.
• The B-C3N4/Mo-BiVO4 heterojunction promoted efficient charge separation at the interface.
• A record applied bias photon-to-current efficiency of 2.67% at 0.54 V vs. RHE was achieved.
• Reduced onset potential and improved optical properties of the photoanode were observed.

Conclusions:

• The combined strategies of Mo doping and B-C3N4/Mo-BiVO4 heterojunction formation offer a powerful approach to enhance PEC water splitting.
• This work provides insights into designing advanced semiconductor materials for efficient solar fuel generation.
• The developed photoanode demonstrates significant potential for practical applications in renewable energy conversion.