Cooperation between single atom catalyst and support to promote nitrogen electroreduction to ammonia: A theoretical insight

Abstract

The co-catalysis between single atom catalyst (SAC) and its support has recently emerged as a promising strategy to synergistically boost the catalytic activity of some complex electrochemical reactions, encompassing multiple intermediates and pathways. Herein, we utilized defective BC3 monolayer-supported SACs as a prototype to investigate the cooperative effects of SACs and their support on the catalytic performance of the nitrogen reduction reaction (NRR) for ammonia (NH3) production. The results showed that these SACs can be firmly stabilized on these defective BC3 supports with high stability against aggregation. Furthermore, co-activation of the inert N2 reactant was observed in certain embedded SACs and their neighboring B atoms on the certain BC3 sheets due to the noticeable charge transfer and significant N–N bond elongation. Our high-throughput screening revealed that the Mo/DVCC and W/DVCC exhibit superior NRR catalytic performance, characterized by a low limiting potential of −0.33 and −0.43V, respectively, which can be further increased under acid conditions based on the constant potential method. Moreover, varying NRR catalytic activities can be attributed to the differences in the valence state of active sites. Remarkably, further microkinetic modeling analysis displayed that the turnover frequency of N2–to–NH3 conversion on Mo/DVCC is as large as 1.20 × 10−3 s−1 site−1 at 700 K and 100 bar, thus guaranteeing its ultra-fast reaction rate. Our results not only suggest promising advanced electrocatalysts for NRR, but also offered an effective avenue to regulate the electrocatalytic performance via the co-catalytic metal–support interactions.