In-situ synthesized N-doped ZnO for enhanced CO2 sensing: Experiments and DFT calculations

Chemiresistive CO2 sensing is attractive due to low cost and ease of chip-level integration. Our previous studies (Yong Xia, 2021) showed the well-developed ZnO material fabricated by in-situ annealing exhibited good performance. Here, we have expanded on those studies, including cyclic tests under both dry air N2 background whereby a much higher response in was observed. Detailed density functional theory calculations were conducted understand behavior. The results indicated nitrogen doping mainly responsible for observed response. In presence pre-adsorbed O2, N-doped can no longer interact with CO2, which agrees well observation background. Furthermore, states analysis N sp2 hybridized orbital 2p dopant mixed C atom orbitals C/O atoms form σ π bonds, respectively. However, they O 2s/2p O2 when present, hindering interaction ZnO, resulting limited air. illustrated mechanism does not only further understanding metal oxide-based sensing, but also guide design new materials or capture.