Single-Atom Metal Anchored Zr₆-Cluster-Porphyrin Framework Hollow Nanocapsules with Ultrahigh Active-Center Density for Electrocatalytic CO₂ Reduction.

Abstract

Designing earth-abundant electrocatalysts toward highly efficient CO₂ reduction has significant importance to decrease the global emission of greenhouse gas. Herein, we propose an efficient strategy to anchor non-noble metal single atoms on Zr₆-cluster-porphyrin framework hollow nanocapsules with well-defined and abundant metal-N₄ porphyrin sites for efficient electrochemical CO₂ reduction. Among different transition metal single atoms (Mn, Fe, Co, Ni, and Cu), Co single-atom anchored Zr₆-cluster-porphyrin framework hollow nanocapsules demonstrated the highest activity and selectivity for CO production. The rich Co-N₄ active centers and hierarchical porous structure contribute to enhanced CO₂ adsorption capability and moderate binding strength of reaction intermediates, thus facilitating *CO desorption and CO₂-to-CO conversion. The Co-anchored nanocapsules maintain high efficiency and well-preserved stability during long-term electrocatalysis tests. Moreover, the Co-anchored nanocapsules exhibit a remarkable solar-to-CO energy conversion efficiency of 12.5% in an integrated solar-driven CO₂ reduction/O₂ evolution electrolysis system when powered by a custom large-area [Cs_0.05(FA_0.85MA_0.15)_0.95]Pb_0.9(I_0.85Br_0.15)₃-based perovskite solar cell.