Deciphering the dynamic behavior of geminal-Cu sites for high-efficiency reduction of nitrate to ammonia

Abstract

The nitrate reduction reaction (NO₃RR), an innovative dual technology for water pollution remediation and ammonia (NH₃) production, has emerged as an effective strategy to address the imbalances in the global nitrogen cycle. In this work, the catalytic behavior of a novel 2D material featuring geminal-Cu (Cu_g) atoms anchored on polymeric carbon nitride (Cu_g/PCN) for the NO₃RR was analyzed via density functional theory calculations. The results reveal that the electronic delocalization of the Cu_g/PCN catalytic material and the d–p orbital coupling between Cu_g atoms and nearby N atoms can modify the electronic structure of the active site, boosting the activation of nitrate. The dynamic change of the Cu–Cu distance facilitates to the formation of the *NHO intermediate rather than *NOH through a bridging mechanism, which results in a remarkably low potential-determining step of 0.02 eV and superior NO₃RR performance. This work identifies a structure–activity relationship of Cu_g/PCN for the NO₃RR, which offers feasible theoretical and experimental guidance for designing materials based on geminal-metal atoms.