Disordered Au Nanoclusters for Efficient Ammonia Electrosynthesis.

The electrochemical nitrogen (N 2 ) reduction reaction (N 2 RR) under mild conditions is a promising and environmentally friendly alternative to the traditional Haber-Bosch process with high energy consumption and greenhouse emission for the synthesis of ammonia (NH 3 ), but high-yielding production is rendered challenging by the strong nonpolar N≡N bond in N 2 molecules, which hinders their dissociation or activation. In this study, disordered Au nanoclusters anchored on two-dimensional ultrathin Ti 3 C 2 T x MXene nanosheets are explored as highly active and selective electrocatalysts for efficient N 2 -to-NH 3 conversion, exhibiting exceptional activity with an NH 3 yield rate of 88.3±1.7 μg h -1  mg cat. -1 and a faradaic efficiency of 9.3±0.4 %. A combination of in situ near-ambient pressure X-ray photoelectron spectroscopy and operando X-ray absorption fine structure spectroscopy is employed to unveil the uniqueness of this catalyst for N 2 RR. The disordered structure is found to serve as the active site for N 2 chemisorption and activation during the N 2 RR process.