Ti─N Bonding‐Induced Bifunctional Electronic Structure Modulation Enhances NO ₂ Sensing Performance

ABSTRACT Developing gas‐sensing materials that simultaneously offer high electrical conductivity and rich surface reactivity remains a key challenge for next‐generation Nitrogen dioxide (NO 2 ) detectors. Here, we propose an ammonia‐assisted nitridation strategy to introduce Ti─N bonds into TiZrO 4 , thereby generating TiZrON‐10 h with facilitated charge transport and enhanced surface reactivity. The nitridation process narrows the bandgap, raises the Fermi level, and induces Ti─N‐related species together with Ti 3 + enrichment and oxygen‐vacancy‐related donor states, which collectively enhance charge transport and NO 2 adsorption/charge‐transfer processes. As a result, the optimized TiZrON‐10 h sensor delivers a current response of 135 nA to 0.5 ppm NO 2 —22 times that of pristine TiZrO 4 . These improvements arise from a coupled nitridation‐induced electronic reconstruction involving Ti─N coordination, Ti 3 + enrichment, and oxygen‐vacancy‐related donor states, which jointly optimize charge transport and surface reaction activity. This work demonstrates a cost‐effective route to dynamic NO 2 sensing and supports continuous, accurate air‐quality management.