Transition metal oxides (NiO, SnO2, In2O3) modified graphene: A promising candidate to detect and scavenge CO, C2H2, and CH4 gases

This work conducted a density functional theory study on CO, C2H2, and CH4 gases adsorption on transition metal oxides (NiO, SnO2, In2O3) modified graphene monolayer. The application prospects of NiO/SnO2/In2O3 modified graphene monolayer in adsorbents and gas-sensitive materials are discussed from the aspects of modified model, band structure, synergistic effect, adsorption energy, adsorption distance, adsorption structure, electron transfer, and density of state. The three transition metal oxides are modified at three optimal positions on the graphene monolayer, which improves the conductivity of the intrinsic graphene monolayer. NiO-graphene monolayer has the largest adsorption energy for CO gas by obvious chemical interaction. The introduction of transition metal oxides on the intrinsic graphene monolayer significantly enhances the chemical interaction between the graphene monolayer and C2H2 gas. Still, it cannot increase the adsorption energy of CH4 gas. In addition, the electronic properties, desorption performance, and comparative process analysis of all adsorption structures were also studied to evaluate their potential applications for specific gas detection and removal in oil-immersed power transformers.