Structural Reconstruction of Cu 2 O Superparticles toward Electrocatalytic CO 2 Reduction with High C 2+ Products Selectivity.

Structural reconstruction is a process commonly observed for Cu-based catalysts in electrochemical CO 2 reduction. The Cu-based precatalysts with structural complexity often undergo sophisticated structural reconstruction processes, which may offer opportunities for enhancing the electrosynthesis of multicarbon products (C 2+ products) but remain largely uncertain due to various new structural features possibly arising during the processes. In this work, the Cu 2 O superparticles with an assembly structure are demonstrated to undergo complicated structure evolution under electrochemical reduction condition, enabling highly selective CO 2 -to-C 2+ products conversion in electrocatalysis. As revealed by electron microscopic characterization together with in situ X-ray absorption spectroscopy and Raman spectroscopy, the building blocks inside the superparticle fuse to generate numerous grain boundaries while those in the outer shell detach to form nanogap structures that can efficiently confine OH - to induce high local pH. Such a combination of unique structural features with local reaction environment offers two important factors for facilitating C-C coupling. Consequently, the Cu 2 O superparticle-derived catalyst achieves high faradaic efficiencies of 53.2% for C 2 H 4 and 74.2% for C 2+ products, surpassing the performance of geometrically simpler Cu 2 O cube-derived catalyst and most reported Cu electrocatalysts under comparable conditions. This work provides insights for rationally designing highly selective CO 2 reduction electrocatalysts by controlling structural reconstruction.