Hetero-type dual photoanodes for unbiased solar water splitting with extended light harvesting.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27966548.
- Also identified by DOI 10.1038/ncomms13380 and PMC identifier 5477502.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Metal oxide semiconductors are promising photoelectrode materials for solar water splitting due to their robustness in aqueous solutions and low cost. Yet, their solar-to-hydrogen conversion efficiencies are still not high enough for practical applications. Here we present a strategy to enhance the efficiency of metal oxides, hetero-type dual photoelectrodes, in which two photoanodes of different bandgaps are connected in parallel for extended light harvesting. Thus, a photoelectrochemical device made of modified BiVO<sub>4</sub> and α-Fe<sub>2</sub>O<sub>3</sub> as dual photoanodes utilizes visible light up to 610 nm for water splitting, and shows stable photocurrents of 7.0±0.2 mA cm<sup>-2</sup> at 1.23 V<sub>RHE</sub> under 1 sun irradiation. A tandem cell composed with the dual photoanodes-silicon solar cell demonstrates unbiased water splitting efficiency of 7.7%. These results and concept represent a significant step forward en route to the goal of >10% efficiency required for practical solar hydrogen production.