Sunlight-driven valorization of CO2 into fuels is a promising solution to renewable energy storage, but the design of an integrated and efficient solar-to-chemical conversion system remains challenging. Herein, an all-solar-driven artificial photosynthetic system (APS) by tailoring photovoltaic-photoelectrochemical cell which can efficiently produce formic acid fuel from CO2 and H2O with bias-free illumination is demonstrated. Guided by density functional theory (DFT) calculations, a BiOI–Bi (BOI–Bi) cathode catalyst is synthesized, which is highly selective for CO2 to HCOOH conversion, and coupled with a single crystalline argon-treated TiO2 (TiO2-Ar) photoanode, whose valence band edge is beneficial for the oxidation of H2O to O2. The APS exhibits high product selectivity, robust activity and good durability. A solar-to-HCOOH selectivity of 96.5% is obtained with a HCOOH yield of 108.2 mmol g−1 h−1 under bias-free illumination of AM1.5G. The device can operate stably for at least 12 h. In particular, an apparent photon quantum efficiency of 7.5% and a solar-to-chemical conversion efficiency (ηSCC) of 8.3% are recorded, rivaling all the incumbent precious-metal-free all-solar-driven components for CO2-to-HCOOH conversion. This study highlights the potential of BOI-Bi for CO2 to HCOOH conversion with high selectivity and its integration into APS system to realize carbon-negative solar-to-chemical conversion with industrial relevance.
|Original language||English (US)|
|Journal||Journal of Power Sources|
|State||Published - Sep 20 2021|
Bibliographical noteKAUST Repository Item: Exported on 2021-11-20
Acknowledged KAUST grant number(s): BAS/1/1413-01-01
Acknowledgements: This work was financially supported by National Key R&D Program of China (2018YFE0208500) and the National Natural Science Foundation of China (Grants No. 22072022, 21773031, 22011530144). X. L. was funded by King Abdullah University of Science and Technology (KAUST) through the baseline funding (BAS/1/1413-01-01).
ASJC Scopus subject areas
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering
- Renewable Energy, Sustainability and the Environment