Optimizing Intermediate Adsorption via Heteroatom Ensemble Effect over RuFe Bimetallic Alloy for Enhanced Nitrate Electroreduction to Ammonia

摘要

The electrochemical nitrate reduction reaction (NO_3RR) is a promisingapproach for nitrate removal and NH_3 synthesis at ambient conditions. As acomplex eight-electron/nine-proton transfer process, its performance reliesheavily on the adsorption ability of reaction intermediates on the catalystsurface, which is determined by the geometric and electronic configurationsof active sites. In this work, a heteroatom ensemble effect is deliberatelytriggered over RuFe bimetallic alloy to optimize intermediate adsorption forNO_3RR. A record-high NH_3 yield rate of 118.8 mg h~(?1) mg~(?1) and a highFaradaic efficiency of 92.2% are achieved at ?1.4 V vs reversible hydrogenelectrode, ranking at the top of the state-of-the-art. Experimental andcomputational results reveal that the geometric and electronic characteristicsof the induced heteroatom ensemble effect play crucial roles. Both Ru and Fedisplay a continuous state throughout the Fermi level, suggesting highelectron density benefits the whole NO_3RR. As a result, facilitated adsorptionof NO_3~?, efficient stabilization of key intermediates, as well as the timelydesorption of NH_3 are simultaneously achieved, thus significantly promotingthe direct reduction of NO_3~? to NH_3.