Single Nb atom modified anatase TiO₂(110) for efficient electrocatalytic nitrogen reduction reaction

We report the theory-guided design of anatase-supported Nb catalysts for electrochemical N-2 reduction reaction (NRR). Theoretical calculations predict that Nb atoms deliver multi-functional enhancement toward the NRR when incorporated in an anatase TiO2(110) catalyst: (1) decreasing the band gap and inducing electrons to promote the conductivity of TiO2( 110); (2) suppressing the undesired competitive hydrogen evolution reaction; (3) activating the inert Ti sites for N-2 adsorption; ( 4) enabling fast charge transfer between *NNH and the TiO2(110) surface; and (5) reducing the energy barrier of the potential-determining * N-2 -> * NNH step, further facilitating NH3 formation. As a result, our Nb-TiO2(110) catalyst exhibits superior activity and selectivity for the NRR, which affords an NH3 production rate of about 21.3 mu g h(-1) mg(cat)(-1) and NH3 faradaic efficiency of similar to 9.2% at -0.5 V (versus reversible hydrogen electrode). This study provides insights for the rational design of efficient electrocatalysts for the NRR.