Distorting Square-Planar Cu Using Adjacent La Atom Optimizes Electrocatalytic Nitrate Reduction.

Electrocatalytic conversion of nitrate to ammonia is a rapidly evolving field due to its potential applications toward nitrate pollution remediation and sustainable ammonia synthesis. As a group of well-established electrocatalysts, the activity of Cu-based materials is highly related to the coordination environment. Herein, a novel Cu-La-based dual-atom catalyst (Cu-La/DAC) was prepared using a Robson-type bimetallic Cu-La complex as precursor, where the square-planar Cu center of Cu-La/DAC effectively deviates due to the presence of adjacent La atom. As a result, the HOMO (dxy) energy of Cu is effectively reduced, which facilitates the formation of low-valent Cu and subsequent electrocatalysis. Compared to Cu2/DAC analogue containing square-planar Cu, Cu-La/DAC exhibits significantly enhanced activity toward electrocatalytic nitrate (NO3-) reduction to ammonia (NH3) (yield: 14.02 mg h-1 cm-2; Faraday efficiency: 88.42%), which is theoretically attributed to the reduced energy barrier of NO3- adsorption and *NO3 deoxygenation induced upon the coordination environment modulation of Cu.