Dual functionalized Ni substitution in shuttle-like In2O3 enabling high sensitivity NH3 detection

• Published in: Applied surface science 2022-10, Vol.600, p.154158, Article 154158
• Main Authors: Li, Ying-Ying, Chen, Jun-Li, Gong, Fei-Long, Jin, Gui-Xin, Xie, Ke-Feng, Yang, Xuan-Yu, Zhang, Yong-Hui
• Format: Article
• Language: English
• Subjects: Gas sensing; NH3; Reactive O−(ad) species; Shuttle-like Ni-doped In2O3 nanostructure; Substitution; Surface acidity
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.154158

[Display omitted] •Dual functionalized Ni substitution in shuttle-like In2O3 nanoparticles (NPs) has been synthesized.•The 2 wt% Ni-doped In2O3 NPs exhibit high sensitivity (Ra/Rg = 2569.42 towards 50 ppm NH3 at 140 °C), achieving 34 folds improvement compared with pristine In2O3 NPs.•Ni substitution in rh-In2O3 NPs can effectively modulate the electronic structure and surface acidity of material and further improve the adsorption of NH3.•The substitution of Ni in rh-In2O3 phase and surface O−(ad) species neighboring the substitution sites are recognized as the active sites. Hetero-atom doping is an effective way to improve the sensing performance of metal oxide semiconductor gas sensors. However, the synergistic effects generated from hetero-atom substitution in In2O3 lattice and the relationship between the fine surface structure and sensing performance is still ambiguous. Here, Ni substitution in shuttle-like In2O3 nanoparticles have been successfully synthesized, and the materials are fabricated as gas sensor to detect ammonia, which is a toxic molecule that is harmful for human healthy. We find the 2 wt% Ni-doped In2O3 NPs exhibit high sensitivity (Ra/Rg = 2569.42 towards 50 ppm NH3 at 140 °C), achieving 34 folds improvement compared with pristine In2O3 NPs. The sensor also shows good long-term stability, high selectivity and fast response/recovery (23/10 s). Detail structural analysis illustrate the substitution of Ni in rh-In2O3 phase and surface O−(ad) species neighboring the substitution sites are recognized as the active sites, and the reactive oxygen species and surface Bronster acidity can be dramatically enhanced after Ni modification, which contribute to the improvement of sensing performance. Our work illustrate the synergistic effects of hetero-atom doping on the sensing performance and pave the way for design of high performance sensing materials.