Facet-Dependent Gas Adsorption Selectivity on ZnO: A DFT Study
Weile Jiang,
Yong Xia,
Aifei Pan,
Yunyun Luo,
Yaqiong Su,
Sikai Zhao,
Tao Wang,
Libo Zhao
Affiliations
Weile Jiang
School of Humanities and Social Science, Institute of Heritage Sites & Historical Architecture Conservation, Xi’an Jiaotong University, Xi’an 710049, China
Yong Xia
State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and System, Xi’an Jiaotong University, Xi’an 710049, China
Aifei Pan
School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Yunyun Luo
State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and System, Xi’an Jiaotong University, Xi’an 710049, China
Yaqiong Su
School of Chemistry, Xi’an Key Laboratory of Sustainable Energy Materials Chemistry, Xi’an Jiaotong University, Xi’an 710049, China
Sikai Zhao
School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China
Tao Wang
State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and System, Xi’an Jiaotong University, Xi’an 710049, China
Libo Zhao
State Key Laboratory for Manufacturing Systems Engineering, International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies, Xi’an Jiaotong University (Yantai) Research Institute for Intelligent Sensing Technology and System, Xi’an Jiaotong University, Xi’an 710049, China
Semiconductor-based gas sensors are of great interest in both industrial and research settings, but poor selectivity has hindered their further development. Current efforts including doping, surface modifications and facet controlling have been proved effective. However, the “methods-selectivity” correlation is ambiguous because of uncontrollable defects and surface states during the experiments. Here, as a case study, using a DFT method, we studied the adsorption features of commonly tested gases—CH2O, H2, C2H5OH, CH3COCH3, and NH3—on facets of ZnO(0001¯), ZnO(101¯0) and ZnO(101¯1). The adsorption energies and charge transfers were calculated, and adsorption selectivity was analyzed. The results show ZnO(0001¯) has obvious CH2O adsorption selectivity; ZnO(101¯0) has a slight selectivity to C2H5OH and NH3; and ZnO(101¯1) has a slight selectivity to H2, which agrees with the experimental results. The mechanism of the selective adsorption features was studied in terms of polarity, geometric matching and electronic structure matching. The results show the adsorption selectivity is attributed to a joint effort of electronic structure matching and geometric matching: the former allows for specific gas/slab interactions, the latter decides the strength of the interactions. As the sensing mechanism is probably dominated by gas–lattice interactions, this work is envisioned to be helpful in designing new sensing material with high selectivity.
