In Situ Hydrothermal Growth of TiO₂ Nanoparticles on a Conductive Ti₃C₂Tx MXene Nanosheet: A Synergistically Active Ti-Based Nanohybrid Electrocatalyst for Enhanced N₂ Reduction to NH₃ at Ambient Conditions

The traditional power-wasting Haber-Bosch process still dominates industrial NH3 production. Recent years witnessed the rapid development of an electrochemical N2 reduction reaction (NRR) because of its environmentally benign and sustainable feature. Here, we demonstrate the first utilization of a Ti3C2T x MXene nanosheet as both the precursor and conductive substrate toward the in situ hydrothermal growth of TiO2 nanoparticles. The marriage of TiO2 and Ti3C2T x leads to a synergistically active Ti-based nanohybrid catalyst that can strengthen N2 reduction electrocatalysis. When tested in 0.1 M HCl, such a TiO2/Ti3C2T x hybrid is superior in catalytic performance, capable of affording a NH3 yield of 26.32 μg h-1 mg-1cat. with a 8.42% Faradaic efficiency (FE) at -0.60 V versus reversible hydrogen electrode (RHE), larger than those for TiO2 and Ti3C2T x. Notably, this nanohybrid also shows good NH3 selectivity with high electrochemical durability.