The gas sensing and adsorption properties of XO2 (X = Ti, Zr, Hf) doped C3N towards H2S, SO2, SOF2: A first-principles study

Abstract

In this paper, XO 2 (X = Ti, Zr, Hf) doped C 3 N nanosheet is firstly proposed to detect SF 6 decomposition products: H 2 S, SO 2 , and SOF 2 . The electronic properties and adsorption mechanisms of XO 2 (X = Ti, Zr, Hf) doped C 3 N nanosheet towards H 2 S, SO 2 , SOF 2 are systematically explored. Metal oxide particles doping effectively modulate the band gap, with the decline of 27.8 %, 22.3 % and 42.6 % in TiO 2 , ZrO 2 and HfO 2 doped systems, furthermore, dopants provide abundant active sites for gas adsorption and enhance electron mobility and electrical conductivity of the pristine C 3 N surface. TiO 2 -C 3 N holds the best adsorption performance among three doping systems, in which the E ads reach up to −1.158 eV, −2.238 eV, −1.574 eV in H 2 S, SO 2 and SOF 2 systems. The τ of H 2 S, SO 2 , SOF 2 escape from TiO 2 -C 3 N surface are 3.7 × 10 7 s, 4.8 × 10 14 s, 6.88 × 10 25 s. Improved adsorption energy of TiO 2 -C 3 N is twice than that of pristine C 3 N nanosheet's. ZrO 2 , HfO 2 -C 3 N have semblable adsorption capacity to target gases. In SO 2 and SOF 2 adsorption of HfO 2 doped systems, SO 2 and SOF 2 obtained the charges of 0.303 e and 0.189 e respectively. The results provide a theoretical basis for further manufacture of industrial hazardous gas sensors and online monitoring of SF 6 insulated equipment. • XO 2 (X=Ti, Zr, Hf) nanoparticle modification is firstly proposed to improve C 3 N’s surface electronic properties. • Transition metal oxides doped C 3 N exhibits ideal adsorption and scavenging properties for H 2 S, SO 2 , and SOF 2 . • The results provide a theoretical basis for further manufacture of industrial hazardous gas sensors and online monitoring of SF 6 insulated equipment.