Hydrogen sensing and mechanism of M-doped SnO2 (M = Cr3+, Cu2+ and Pd2+) nanocomposite

The microstructure of M-doped SnO2 (M = Cr3+, Cu2+ and Pd2+) prepared by the sol–gel method and their gas-sensing performance were investigated. In particular, we focus on the effects of metallic ions on the hydrogen sensing behavior of the SnO2-based sensor. It is found that hydrogen gas response of SnO2 can be enhanced evidently by adding Pd2+, while such effect from Cr3+ and Cu2+ exhibits somewhat slight. A theoretical study based on first principles calculation shows that SnO2–Pd (1 1 0) surface enable adsorb more H2 gas and receive larger electrons from adsorbed H2 molecule, thereby holding the potential for the improvement of gas response to hydrogen.