Tin dioxide is a low-cost and efficient material with large potential in applications of hydrogen detection. Doping metals in SnO₂ is a solution to further improve its electrical performance, however, atomic-scale understanding of detection mechanism of doped SnO₂ is very limited. In this work, first principles and molecular dynamics method are applied to investigate adsorption properties and diffusion effects of CH₄, CO₂, H₂, N₂ on Rh-doped SnO₂. By calculating adsorption energy, adsorption distance, charge density difference, density of states, it is concluded that Rh-SnO₂ shows a strong sensing characteristics towards H₂, which is consistent with experiment result. After adsorption of H₂, the main energy bands of DOS shift to a lower level of energy, and the Fermi level move to higher level of energy. H₂ shows a strong chemical adsorption effect on Rh-SnO₂, while CH₄, CO₂ and N₂ only present weak physical adsorption on Rh-SnO₂. Furthermore, the diffusion of H₂ in Rh-SnO₂ is easier than those of other gases. Our study provides a fundamental and new perspective for designing highly sensitive hydrogen gas sensor from atomic and electronic level.

二氧化锡是一种低成本、高效的材料，在氢气检测中具有很大的应用潜力。_{在SnO 2}中掺杂金属是进一步提高其电性能的一种解决方案，但是，对掺杂SnO ₂的检测机制的原子级理解非常有限。本工作采用第一原理和分子动力学方法研究了CH ₄、CO ₂、H ₂、N ₂对Rh掺杂SnO ₂的吸附性能和扩散效应。通过计算吸附能、吸附距离、电荷密度差、态密度，得出Rh-SnO ₂对H表现出很强的传感特性。₂，与实验结果一致。吸附H ₂后，DOS的主要能带向低能级移动，费米能级向高能级移动。H _{2对Rh-SnO 2}表现出较强的化学吸附作用，而CH ₄、CO ₂和N ₂仅对Rh-SnO ₂表现出较弱的物理吸附作用。此外，H ₂在Rh-SnO ₂中的扩散比其他气体更容易。我们的研究为从原子和电子水平设计高灵敏度氢气传感器提供了基本和新的视角。