Size-effect induced controllable Cu0-Cu+ sites for ampere-level nitrate electroreduction coupled with biomass upgrading

The synergistic Cu0-Cu+ sites is regarded as the active species towards NH3 synthesis from the nitrate electrochemical reduction reaction (NO3-RR) process. However, the mechanistic understanding and the roles of Cu0 and Cu+ remain exclusive. The big obstacle is that it is challenging to effectively regulate the interfacial motifs of Cu0-Cu+ sites. In this paper, we describe the tunable construction of Cu0-Cu+ interfacial structure by modulating the size-effect of Cu2O nanocube electrocatalysts to NO3-RR performance. We elucidate the formation mechanism of Cu0-Cu+ motifs by correlating the macroscopic particle size with the microscopic coordinated structure properties, and identify the synergistic effect of Cu0-Cu+ motifs on NO3-RR. Based on the rational design of Cu0-Cu+ interfacial electrocatalyst, we develop an efficient paired-electrolysis system to simultaneously achieve the efficient production of NH3 and 2,5-furandicarboxylic acid at an industrially relevant current densities (2 A cm−2), while maintaining high Faradaic efficiencies, high yield rates, and long-term operational stability in a 100 cm2 electrolyzers, indicating promising practical applications. It is challenging to regulate the interfacial motifs of Cu0-Cu+ sites to understand roles of Cu0 and Cu+ for nitrate electrochemical reduction reaction. Here, the authors report a tunable construction of Cu0-Cu+ interfacial structure by modulating the size-effect of Cu2O electrocatalysts.