Sacrificial Leaching Enables Fe-Rich Oxyhydroxide Reconstruction on In₂S₃ Photoanode

Abstract

Photoelectrochemical (PEC) water splitting is often constrained by interfacial recombination and sluggish oxygen evolution, highlighting the importance of constructing efficient catalytic junctions on photoanodes. Here, we report that a brief PEC activation restructures a photodeposited NiFe oxyhydroxide layer on In₂S₃ into a self-optimized catalytic interface through sacrificial Ni leaching-induced interfacial reconstruction. Activation triggers selective Ni leaching and simultaneous surface porosification, generating an amorphous FeOOH-like overlayer that is intimately coupled to the sulfide surface. Spectroscopic, kinetic, and theoretical analyses indicate that reconstruction strengthens electronic coupling, suppresses carrier recombination, and lowers charge-transfer resistance at both the semiconductor/cocatalyst and cocatalyst/electrolyte interfaces. Consequently, the activated photoanode delivers 9.58 mA cm⁻² at 1.23 V versus reversible hydrogen electrode, placing its performance among the best reported for oxide and sulfide photoanodes under comparable conditions. Beyond performance enhancement, this work highlights operando interface reconstruction as a powerful route for transforming static cocatalyst contacts into dynamically optimized catalytic junctions, providing new insights for the design of high-efficiency solar water oxidation systems.

Keywords

NiFeOOH / photoelectrochemical / reconstruction / water splitting

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