Accelerated N2 reduction kinetics in hybrid interfaces of NbTiO4 and nitrogen-doped carbon nanorod via synergistic electronic coupling effect

Electrochemical ammonia synthesis through the atmospheric nitrogen reduction reaction (NRR) is a promising method for sustainable fertilizer and carbon-free hydrogen energy carriers. The inevitable selectivity gap against hydrogen evolution reaction and inert nitrogen (N-2) hinders the device-level usage of nitrogen cathodes. In this work, we report engineered electrocatalyst/support interface of NbTiO4 nanoparticles supported on nitrogen doped carbon nanorods (NbTiO4@NCNR) to catalyze NRR. Insisted by the pitfalls to rationally design N-2 reduction catalysts, the strong catalyst-support interaction strategy is adapted to tune the selectivity towards NRR. Electrochemical tests reveal that NbTiO4@NCNR hybrid accelerates a 10-fold increase in N-2 selectivity compared to pure metal oxide. Using first-principles calculations, we identify the underlying mechanism of enhanced performance: bridging bonds in the interface as electron transport channels to promote the N-2 reduction kinetics. Essentially, this study provides an insight into how to overcome the immense kinetic barrier of NRR using smartly engineered interfaces of hybrid materials.

Automated summary

This study reports the engineering of an electrocatalyst/support interface to enhance the selectivity of nitrogen cathodes for the electrochemical synthesis of ammonia. By utilizing a strong catalyst-support interaction strategy, the NbTiO4@NCNR hybrid exhibits a 10-fold increase in selectivity compared to pure metal oxide. The enhanced performance is attributed to bridging bonds in the interface that facilitate electron transport and promote the kinetics of nitrogen reduction.