In situ oxidative etching-enabled synthesis of hollow Cu2O nanocrystals for efficient CO2RR into C2+ products

Multicarbon (C2+) products are one of the most attractive carbon-based chemicals that can be manufactured through the CO2 electroreduction reaction (CO2RR), but they face challenges of low current density and poor selectivity due to unsatisfactory catalysts. Herein, we report the fabrication of hollow Cu2O nanocrystals with defect-rich sites and abundant stepped facets and the investigation of their applications as electrocatalysts in the CO2RR. In particular, the reduction of self-made Cu precursor, Cu-2(OAc)(4)(py)(2), at an elevated temperature, leads to the formation of polyhedral Cu nanoparticles in advance, followed by bubbling gaseous oxygen to proceed with in situ oxidative etching. Ascribed to structural advantages, a remarkable faradaic efficiency of 75.9% and partial current density of 0.54 A cm(-2) are actualized for C2+ products. Impressively, hollow Cu2O catalysts can generate n-propanol with faradaic efficiencies of up to 8.21% due to the boosted C-C coupling step for C3+ production. Density functional theory (DFT) calculations reveal that the high CO coverage and the high index planes of Cu2O can enhance the C-C coupling reaction. The current work offers an effective crystal engineering route to the rational design of CO2RR electrocatalysts with boosted electrochemical activity and selectivity of C2+ products.

Automated summary

The study presents the fabrication of hollow Cu2O nanocrystals with defect-rich sites and abundant stepped facets for use as electrocatalysts in CO2RR, achieving remarkable faradaic efficiency and partial current density for C2+ products. Furthermore, the hollow Cu2O catalysts demonstrate the ability to generate n-propanol with high faradaic efficiency due to enhanced C-C coupling step for C3+ production.