Surface Composition Impacts Selectivity of ZnTe Photocathodes in Photoelectrochemical CO<sub>2</sub> Reduction Reaction
Guosong Zeng, Guiji Liu, Gabriele Panzeri, Chanyeon Kim, Chengyu Song, Olivia Alley, Alexis T. Bell, Adam Z. Weber, Francesca M. Toma
Abstract
High Resolution Image Download MS PowerPoint Slide Light-driven reduction of CO 2 into chemicals using a photoelectrochemical (PEC) approach is considered as a promising way to meet the carbon neutral target. The very top surface of the photoelectrode and semiconductor/electrolyte interface plays a pivotal role in defining the performance for PEC CO 2 reduction. However, such impact remains poorly understood. Here, we report an electrodeposition-annealing route for tailoring surface composition of ZnTe photocathodes. Our work demonstrates that a Zn-rich surface on the ZnTe photocathode is essential to impact the CO 2 reduction activity and selectivity. In particular, the Zn-rich surface not only facilitated the interfacial charge carrier transfer, but also acted as electrocatalyst for boosting carbon product selectivity and suppressing the hydrogen evolution reaction. This work provides a new avenue to optimize the photocathode, as well as improvement of the CO 2 RR performance.