Bifunctional Perovskite‐BiVO4 Tandem Devices for Uninterrupted Solar and Electrocatalytic Water Splitting Cycles

• Published in: Advanced functional materials Vol. 31; no. 15
• Main Authors: Pornrungroj, Chanon, Andrei, Virgil, Rahaman, Motiar, Uswachoke, Chawit, Joyce, Hannah J., Wright, Dominic S., Reisner, Erwin
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01-04-2021
• Subjects: Bismuth oxides; Capacity factor; Catalysts; Diurnal variations; Electricity; electrocatalysis; Electrolysis; Fuel production; Fuels; Graphite fiber reinforced plastics; Graphite-epoxy composites; hydrogen; Hydrogen evolution; Irradiation; Lead compounds; Materials science; Metal halides; Oxidation; Perovskites; photoelectrochemistry; solar fuels; Vanadates; Water splitting
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202008182

Photoelectrochemical (PEC) fuel synthesis depends on the intermittent solar intensity of the diurnal cycle and ceases at night. Here, an integrated device that does not only possess PEC water splitting functionality, but also operates as an electrolyzer in the nocturnal period to improve the overall capacity factor is described. The bifunctional system is based on an “artificial leaf” tandem PEC architecture that contains an inverse‐structure lead halide perovskite protected by a graphite epoxy/parylene‐C coating (conferring 96 h stability of operation in water), and a porous BiVO4 semiconductor. The light‐absorbers are interfaced with a H2 evolution catalyst (Pt) and a Co‐based water oxidation catalyst, respectively, which can also be directly driven by electricity. Thus, the device can operate in PEC mode during irradiation and switch to an electricity‐powered mode in the dark through bypassing of the semiconductor configuration. The bifunctional perovskite‐BiVO4 tandem provides a solar‐to‐hydrogen efficiency of 1.3% under simulated solar irradiation and an onset for water electrolysis at 1.8 V. The compact design and low cost of the proposed device may provide an advantage over other technologies for round‐the‐clock fuel production.
The mismatch in demand and supply of sustainable energy sources poses challenges for renewable energy production. Photoelectrocatalysis can directly convert solar energy into storable chemical fuels like hydrogen, but its performance is dependent on external factors (light intensity, weather). Here, hybrid devices that can perform sunlight‐powered water splitting during daytime and switch to water electrolysis at night are proposed.