Cation‐Site Disordered Cu$_3$PdN Nanoparticles for Hydrogen Evolution Electrocatalysis

Transition metal nitrides (TMNs) are emerging as a promising class of materials for application in optoelectronics as well as energy conversion and storage, but they remain rather unexplored, mainly due to a lack of mechanistic understanding of their synthetic pathways. Here, a one-pot synthesis is demonstrated, which yields 3 nm phase-pure Cu$_3$PdN nanoparticles after the reaction of Cu methoxide and Pd acetylacetonate in benzylamine for 5 min at 140 °C. The structure of the initial complexes and their conversion to Cu$_3$PdN are revealed by in situ X-ray absorption spectroscopy measurements and elucidate nucleation and growth of the nitride nanocrystals by in situ total X-ray scattering measurements. Interestingly, extended X-ray absorption fine structure double-edge refinement reveals the presence of short-range cation-site disorder in the anti-perovskite structure of Cu3PdN, which has not been observed before in the Cu3PdN system. Additionally, the synthesized Cu3PdN nanoparticles are tested for the electrocatalytic hydrogen evolution reaction, revealing an overpotential as low as $η_{10}$ = 212 ± 11 mV measured at 10 mA cm$^{−2}$.