Identifying Reactive Sites & Surface Traps in Solar Fuel production
![© 2021 / N. Guijarro EPFL © 2021 / N. Guijarro EPFL](/image/110123/1108x622.jpg)
© 2021 / N. Guijarro EPFL
The LIMNO and LPI laboratories in ISIC team up with UniBe to gain new insights into the operation of CuIn0.3Ga0.7S2 photocathodes for photoelectrochemical hydrogen production
Gathering information on the atomic nature of reactive sites and trap states is key to fine tuning catalysis and suppressing deleterious surface voltage losses in photoelectrochemical technologies for direct solar-to-fuel production. In a new “hot paper” published in Angewandte Chemie, Liu et al. combine spectroelectrochemical and computational methods to investigate a model photocathode from the promising chalcopyrite family: CuIn0.3Ga0.7S2 (CIGS). Interestingly, it was found that voltage losses are linked to traps induced by surface Ga and In vacancies, whereas operando Raman spectroscopy revealed that catalysis occurred at Ga, In, and S sites (not Cu). This result establishes an important bridge between chalcopyrite's performance and its surface's chemistry, where avoiding formation of Ga and In vacancies is crucial for achieving high activity, and is a step towards inexpensive solar-driven H2 production.
This work was supported by the Swiss National Science Foundation (SNSF) under the Ambizione Energy grant (PZENP2_166871) and by the Gaznat-EPFL Research Program. The Swiss National Science Foundation Professorship Grants PP00P2_157615, PP00P2_187185, the China Scholarship Council (No. CSC201806160172) and the Strategic Japanese–Swiss Science and Technology program (514259) are also acknowledged.
Liu, Y., Bouri, M., Yao, L., Xia, M., Mensi, M., Grätzel, M., Sivula, K., Aschauer, U. and Guijarro, N. (2021), Identifying Reactive Sites and Surface Traps in Chalcopyrite Photocathodes. Angew. Chem. Int. Ed.. https://doi.org/10.1002/anie.202108994