Cost-Efficient Photovoltaic-Water Electrolysis over Ultrathin Nanosheets of Cobalt/Iron-Molybdenum Oxides for Potential Large-Scale Hydrogen Production.

Unassisted photovoltaic (PV) water splitting to hydrogen system is of great potential for future environmental-friendly fuel production from renewable solar energy. However, industrialization simultaneously requires higher efficiency, sustained stability and a lower cost for the system. In this work, the ultrathin cobalt/iron-molybdenum oxides nanosheet on nickel foam (NF) is prepared for efficient HER and OER, respectively, delivering a relatively low voltage of 1.45 V at 10 mA cm-2 in two-electrodes configuration. Water electrolysis at low voltage driven by electrocatalysts is critical for realizing energy conversion. Integrated with a commercial monocrystalline silicon cell, the H2 area specific activity of 0.47 L m-2 h-1 is achieved with a solar-to-hydrogen efficiency of 15.1% under solar simulator illumination (100 mW cm-2 ) and no performance degradation appeares over 160 h. Such a solar conversion technology demonstrates the potential for long-term and cost-efficient H2 production in large-scale industrialization and provides an exploration for new-type of energy-conversion system.