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

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