A mesoporous Ni3N/NiO composite with a core–shell structure for room temperature, selective and sensitive NO2 gas sensing

Abstract

A highly crystallized mesoporous Ni₃N with core–shell structure was prepared from a green and template free method. The Ni₃N was characterized by using powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis, and the measured Ni₃N has a specific surface area of 85.89 m² g⁻¹ and a narrow pore size distribution centered at 5 nm. After air oxidization, the Ni₃N/NiO composite was further evaluated for NO₂ gas sensing at room temperature, and the Ni₃N/NiO-based sensor exhibited excellent selectivity for NO₂ gas. A good linear relationship between the sensor response and the NO₂ gas concentrations was observed. The enhanced NO₂ sensing performance can be attributed to the highly crystallized mesoporous and core–shell structures of the synthesized Ni₃N/NiO.