Constructing a interfacial electric field for efficient reduction of nitrogen to ammonia

Abstract

Electrochemical nitrogen reduction (eNRR) is a cost-effective and environmentally sustainable approach for ammonia production. MoS₂, as a typical layered transition metal compound, holds significant potential as an electrocatalyst for the eNRR. Nevertheless, it suffers from a limited number of active sites and low electron transfer efficiency. In this study, we constructed a heterostructure by depositing SnO₂ (an n-type semiconductor) nanoparticles on MoS₂ (a p-type semiconductor). This unique interfacial structure not only generates abundant interfacial contacts but also facilitates the transfer of electrons from SnO₂ to MoS₂, leading to the formation of an interfacial electric field. Theoretical calculations demonstrate that this electric field increases the number of active electrons, facilitating N₂ adsorption and NN bond activation. Moreover, it increases the degree of orbital overlap between N₂ and SnO₂/MoS₂, effectively reducing the energy barrier of the rate-determining step. Benefiting from the interfacial electric field effect, the SnO₂/MoS₂ catalyst exhibits significant catalytic activity and selectivity towards eNRR, with an ammonia yield of 47.1 µg h^-1 mg^-1 and a Faraday efficiency of 19.3 %, surpassing those reported for the majority of MoS₂- and SnO₂-based catalysts.