In Situ Hydrothermal Growth of TiO₂ Nanoparticles on a Conductive Ti₃C₂T_<i>x</i> MXene Nanosheet: A Synergistically Active Ti-Based Nanohybrid Electrocatalyst for Enhanced N₂ Reduction to NH₃ at Ambient Conditions

Abstract

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^-1_cat. 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.