Bottom-up evolution of perovskite clusters into high-activity rhodium nanoparticles toward alkaline hydrogen evolution

Self-reconstruction has been considered an efficient means to prepare efficient electrocatalysts in various energy transformation process for bond activation and breaking. However, developing nano-sized electrocatalysts through complete in-situ reconstruction with improved activity remains challenging. Herein, we report a bottom-up evolution route of electrochemically reducing Cs3Rh2I9 halide-perovskite clusters on N-doped carbon to prepare ultrafine Rh nanoparticles (similar to 2.2nm) with large lattice spacings and grain boundaries. Various in-situ and ex-situ characterizations including electrochemical quartz crystal microbalance experiments elucidate the Cs and I extraction and Rh reduction during the electrochemical reduction. These Rh nanoparticles from Cs3Rh2I9 clusters show significantly enhanced mass and area activity toward hydrogen evolution reaction in both alkaline and chloralkali electrolyte, superior to liquid-reduced Rh nanoparticles as well as bulk Cs3Rh2I9-derived Rh via top-down electro-reduction transformation. Theoretical calculations demonstrate water activation could be boosted on Cs3Rh2I9 clusters-derived Rh nanoparticles enriched with multiply sites, thus smoothing alkaline hydrogen evolution.

Automated summary

In this study, we demonstrate a bottom-up evolution route to prepare ultrafine Rh nanoparticles with large lattice spacings and grain boundaries by electrochemically reducing Cs3Rh2I9 halide-perovskite clusters on N-doped carbon. These Rh nanoparticles derived from Cs3Rh2I9 clusters exhibit significantly enhanced mass and area activity toward hydrogen evolution reaction in both alkaline and chloralkali electrolyte, surpassing liquid-reduced Rh nanoparticles and bulk Cs3Rh2I9-derived Rh via top-down electro-reduction transformation. Theoretical calculations reveal that water activation could be promoted on Cs3Rh2I9 clusters-derived Rh nanoparticles enriched with multiply sites, thereby facilitating alkaline hydrogen evolution.