Photothermal CuS as a Hole Transfer Layer on BiVO₄ Photoanode for Efficient Solar Water Oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Photocatalysis

Background:

• Sluggish hole transport kinetics in bismuth vanadate (BiVO4) limit photoelectrochemical (PEC) water splitting efficiency.
• Efficient solar-to-hydrogen (STH) conversion requires overcoming charge recombination and transport limitations in photoanodes.

Purpose of the Study:

• To enhance the performance of BiVO4 photoanodes for PEC water splitting.
• To investigate the synergistic effects of a copper sulfide (CuS) hole transfer layer (HTL) and photothermal properties.

Main Methods:

• Fabrication of BiVO4/CuS/NiFeCoOx photoanodes.
• Characterization of photoelectrochemical performance.
• Utilizing localized surface plasmon resonance (LSPR) for photothermal enhancement.
• Density functional theory (DFT) calculations for mechanistic insights.

Main Results:

• The CuS HTL facilitated hole transport and suppressed charge recombination.
• Photothermal effects from CuS enhanced water oxidation and charge mobility.
• The optimized BiVO4/CuS/NiFeCoOx photoanode achieved a photocurrent density of 6.56 mA cm-2 at 1.23 VVRHE.
• A STH conversion efficiency of 7.17% was obtained when coupled with Si solar cells.

Conclusions:

• CuS acts as an effective HTL, improving carrier separation and transport in BiVO4 photoanodes.
• The synergistic photothermal effect of CuS significantly boosts PEC water splitting performance.
• Interfacial engineering with CuS offers a promising strategy for developing efficient photoanodes for water splitting.