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

The bigger pictureAn electrochemical N2 reduction reaction (NRR) that can be powered by electricity generated from renewable sources has recently gained heightened research interest, providing a promising alternative to the conventional Haber-Bosch process. Current major research efforts are being devoted to the design and development of advanced electrocatalysts to enhance the efficiency of NRR. Herein, guided by density functional theory calculations that predict the cooperative effect of Nb and anatase TiO2(110) in promoting electrocatalytic NRR performance, we successfully synthesize TiO2 single crystals with selectively exposed (110) facets, supplemented with Nb atomic loading, which exhibited remarkable performance for NRR, achieving an NH3 production rate of ∼21.3 μg h−1 mgcat−1 at −0.5 V (versus reversible hydrogen electrode).Highlights•Nb single-atom-decorated TiO2(110) facilitates nitrogen reduction reaction (NRR)•TiO2(110) is more active than TiO2(101) for NRR•Nb-TiO2(110) delivers an NH3 production rate of ∼21.3 μg h−1 mgcat−1•Single Nb atom modified anatase TiO2(110) for efficient electrocatalytic nitrogen reduction reactionSummaryWe report the theory-guided design of anatase-supported Nb catalysts for electrochemical N2 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 N2 adsorption; (4) enabling fast charge transfer between ∗NNH and the TiO2(110) surface; and (5) reducing the energy barrier of the potential-determining ∗N2 → ∗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 μg h−1 mgcat−1 and NH3 faradaic efficiency of ∼9.2% at −0.5 V (versus reversible hydrogen electrode). This study provides insights for the rational design of efficient electrocatalysts for the NRR.Graphical abstract