Stabilized Cuδ+-OH species on in situ reconstructed Cu nanoparticles for CO2-to-C2H4 conversion in neutral media
Lei Wang, Zhiwen Chen, Yi Xiao, Linke Huang, Xiyang Wang, Holly M. Fruehwald, Dmitry Akhmetzyanov, Mathew Hanson, Zuolong Chen, Ning Chen, Brant Billinghurst, Rodney D. L. Smith, Chandra Veer Singh, Zhongchao Tan, Yimin A. Wu
Abstract
Achieving large-scale electrochemical CO2 reduction to multicarbon products with high selectivity using membrane electrode assembly (MEA) electrolyzers in neutral electrolyte is promising for carbon neutrality. However, the unsatisfactory multicarbon products selectivity and unclear reaction mechanisms in an MEA have hindered its further development. Here, we report a strategy that manipulates the interfacial microenvironment of Cu nanoparticles in an MEA to suppress hydrogen evolution reaction and enhance C2H4 conversion. In situ multimodal characterizations consistently reveal well-stabilized Cuδ+-OH species as active sites during MEA testing. The OH radicals generated in situ from water create a locally oxidative microenvironment on the copper surface, stabilizing the Cuδ+ species and leading to an irreversible and asynchronous change in morphology and valence, yielding high-curvature nanowhiskers. Consequently, we deliver a selective C2H4 production with a Faradaic efficiency of 55.6% ± 2.8 at 316 mA cm−2 in neutral media. The use of membrane electrode assembly electrolyzers in a neutral electrolyte offer potential for large-scale CO2 reduction to multicarbon products, but progress is hindered by low selectivity and unclear reaction mechanisms. Here, the authors regulate the interfacial microenvironment of Cu to stabilize Cuδ + -OH active species for selective C2H4 production.