Transition-metal-embedded carbon nanotubes (CNTs) have been accepted as a novel type of sensing material due to the combined advantage of the transition metal, which possesses good catalytic behavior for gas interaction, and CNTs, with large effective surface areas that present good adsorption ability towards gas molecules. In this work, we simulate the adsorption of O2 and O3 onto Rh-doped CNT in an effort to understand the adsorbing behavior of such a surface. Results indicate that the proposed material presents good adsorbing ability and capacities for these two gases, especially O3 molecules, as a result of the relatively large conductivity changes. The frontier molecular orbital theory reveals that the conductivity of Rh-CNT would undergo a decrease after the adsorption of two such oxidizing gases due to the lower electron activity and density of this media. Our calculations are meaningful as they can supply experimentalists with potential sensing material prospects with which to exploit chemical sensors.

Abstract
 1. Introduction
 2. Computational Details
 3. Results and Discussion
  3.1. Geometric structural analysis of Rh-CNT and gas species
  3.2. Adsorption analysis of O2 and O3 onto the Rh-CNT surface
  3.3. Analyses of DOS and frontier molecular orbital theory
 4. Conclusions
 References

• Hao Cui(State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University)
• Xiaoxing Zhang(State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, School of Electrical Engineering, Wuhan University) Corresponding Author
• Qiang Yao(Chongqing Electric Power Science Academy of State Grid)
• Yulong Miao(Chongqing Electric Power Science Academy of State Grid)
• Ju Tang(School of Electrical Engineering, Wuhan University)