Highly Efficient Hydrogen Production Using a Reformed Electrolysis System Driven by a Single Perovskite Solar Cell

Abstract Efficient hydrogen production by a photovoltaic‐electrolysis cell (PV–EC) system requires a low electrolyzer overpotential and a high coupling efficiency between both the components. Herein, Ni 5 P 4 is proposed as a cost‐effective bifunctional electrocatalyst for hydrogen evolution and hydrazine oxidation in a reformed electrolyzer. Experiments indicate that the electrolytic overpotential could be significantly reduced by replacing the oxygen evolution reaction with the hydrazine oxidation reaction at the anode. Furthermore, a scenario for hydrogen production is demonstrated by utilizing a stable and low‐cost perovskite solar cell (PSC) with a carbon back electrode to drive a reformed electrolyzer. Importantly, a single PSC can drive three reformed electrolyzers in series for hydrogen production by carefully matching the operating point of the electrolyzer with the maximum power point of the photovoltaic device, thereby, yielding a H 2 evolution rate of 1.77 mg h −1 for the whole PV–EC system. This can be a potential starting point for hydrogen production using a single PSC‐driven electrolysis system.