Cation-Site Disordered Cu₃PdN 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 Cu₃PdN 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 Cu₃PdN 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 η₁₀ = 212 ± 11 mV measured at 10 mA cm^-2.