Construction of dual sites on FeS 2 surface for enhanced electrocatalytic reduction of nitrite to ammonia.

Cost-effective iron sulfides (FeS 2 ) hold great potential as high-performance catalysts for NO 2 - electroreduction to NH 3 (NO 2 ER), which is hindered by the weak NO 2 activation. Herein, the design of nonmetal-doped FeS 2 electrocatalysts was initially conducted by density functional theory (DFT) computations. We found that doping with different nonmetal atoms effectively not only regulates the electronic structures of the d-electrons of Fe atoms but also creates the unique p-d hybridized dual active sites, thereby boosting the efficient NO 2 activation. Owing to the optimal NO 2 adsorption strength, N-doped FeS 2 demonstrates a low limiting potential for the NO 2 - -to-NH 3 conversion, thus significantly improving NO 2 ER activity. Direct experimental evidence was provided afterward: an NH 3 yield rate of 424.5 μmol/hcm -2 with a 92.4 % Faradaic efficiency was achieved. Our findings not only suggest a promising NO 2 ER catalyst through theoretical computations to guide experiments but also provide a comprehensive understanding of the structure-properties relationship.