Custom-Made Functions of Active Sites Enabled by High-Entropy Effects toward Efficient Nitrogen Reduction to Ammonia.

Electrocatalytic nitrogen reduction reaction (NRR) enables a sustainable and carbon-free alternative to energy-intensive ammonia synthesis, but unfortunately, undergoes a large bottleneck with its poor activity and selectivity given by the inert N≡N bond and competition from hydrogen evolution reaction (HER), respectively. High-entropy sulfides (HESs) with diversiform compositions provide abundant opportunities for targeted modulations to boost NRR, the development of which is still at the initial stage. Herein, the study pioneers the integration of natural nitrogenase-mimetic components (Fe/Mo/S) with entropy-stabilized Co/Ni/Cr to create a multi-functional active interface toward NRR. The high-entropy effect can induce lattice distortion and electron redistribution to induce the targeted function allocation of active sites, synergistically optimizing N2 adsorption while forming a relatively proton-repelling microenvironment. The (FeCoNiMoCr)9S8 achieves a superior NH3 yield rate of 57.23 µg h-1 mg-1 cat and Faradaic efficiency of 26.42%, surpassing its counterpart of Co9S8 (4.7- and 2.4-fold enhancement) and most reported transition metal sulfides. This work establishes a new entropy-driven interface engineering for catalyst design by combining bio-inspired and entropy-stabilized components to synchronously enhance activity and selectivity, laying the cornerstone of HESs for sustainable ammonia synthesis.