Efficient CO(2) Reduction to Formate on CsPbI(3) Nanocrystals Wrapped with Reduced Graphene Oxide

HIGHLIGHTS: A rational design of metal halide perovskites for achieving efficient CO(2) reduction reaction was demonstrated. The stability of CsPbI(3) perovskite nanocrystal (NCs) in aqueous electrolyte was improved by compositing with reduced graphene oxide (rGO). The CsPbI(3)/rGO catalyst exhibited > 92% Faradaic efficiency toward formate production with high current density which was associated with the synergistic effects between the CsPbI(3) NCs and rGO. ABSTRACT: Transformation of greenhouse gas (CO(2)) into valuable chemicals and fuels is a promising route to address the global issues of climate change and the energy crisis. Metal halide perovskite catalysts have shown their potential in promoting CO(2) reduction reaction (CO(2)RR), however, their low phase stability has limited their application perspective. Herein, we present a reduced graphene oxide (rGO) wrapped CsPbI(3) perovskite nanocrystal (NC) CO(2)RR catalyst (CsPbI(3)/rGO), demonstrating enhanced stability in the aqueous electrolyte. The CsPbI(3)/rGO catalyst exhibited > 92% Faradaic efficiency toward formate production at a CO(2)RR current density of ~ 12.7 mA cm(−2). Comprehensive characterizations revealed the superior performance of the CsPbI(3)/rGO catalyst originated from the synergistic effects between the CsPbI(3) NCs and rGO, i.e., rGO stabilized the α-CsPbI(3) phase and tuned the charge distribution, thus lowered the energy barrier for the protonation process and the formation of *HCOO intermediate, which resulted in high CO(2)RR selectivity toward formate. This work shows a promising strategy to rationally design robust metal halide perovskites for achieving efficient CO(2)RR toward valuable fuels. [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40820-023-01132-3.