Solar-powered overall water splitting system combing metal-organic frameworks derived bimetallic nanohybrids based electrocatalysts and one organic solar cell

Highlights: • Our electrocatalysts obtains high activity and favourable durability in HER and OER. • Our electrolyzer displays a low cell voltage for overall water splitting. • Driven by one novel organic solar cell, our solar-powered hydrogen production system reached a record high efficiency. -- Abstract: Solar-powered water splitting is expected to be a promising route for sustainable hydrogen production. However, its wide implementation is hampered by expensive electrocatalysts and photovoltaic apparatus. Herein, we designed a low-cost overall water splitting system combining flexible catalyst electrodes and one novel organic solar cell. The flexible electrodes contain carbon fabric functionalized with nitrogen-doped carbon encased iron-cobalt bimetallic phosphide and sulfide nanohybrids as electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. The electrolyzer for overall water splitting can realize a current density of 10 mA cm⁻² at a low cell voltage of 1.60 V and remain stable in long-time durability test in alkaline media. Moreover, when driven by one organic solar cell, our system yields a record high water-splitting current density of 7.5 mA cm⁻² with a solar-to-hydrogen efficiency of 9.2%. The above results demonstrate its potential as a real-life solar-powered hydrogen production system.