Bias-Free, High-Rate Solar Hydrogen Production in Alkaline Media with a NiCo-Coupled Perovskite Photocathode

Abstract

Photoelectrochemical (PEC) water splitting provides a sustainable route for hydrogen production from solar energy. In this work, we demonstrate a bias-free PEC cell integrating a perovskite photocathode with a bifunctional NiCo electrocatalyst and pairing it with a NiCo-coated Ni foam anode. To minimize anodic overpotential, the oxygen evolution reaction (OER) is replaced with the hydrazine oxidation reaction (HzOR, E⁰ = −0.33 VRHE), enabling efficient operation under alkaline conditions. This architecture achieves a photocurrent density of –24 mA cm–2 with a photovoltage of 0.99 V under AM 1.5G illumination, among the highest reported for bias-free PEC cell. Beyond solar-to-hydrogen conversion, this system simultaneously detoxifies hydrazine, establishing a dual-functional platform for sustainable fuel production and environmental remediation. These findings highlight the practical potential of integrating high-performance perovskite photoelectrodes with alternative anodic reactions to overcome efficiency and stability barriers in solar-to-hydrogen conversion.