SnO2/CuO nano-hybrid foams synthesized by electrochemical deposition and their gas sensing properties

• SnO2/CuO nano-hybrid foam sensor was fabricated using electrochemical deposition.
• SnO2/CuO foam was macro-porous and composed of self-supported nano-sized dendrites.
• Nano-hybrid foams sensor exhibited enhanced sensitivity and selectivity toward H2S.

SnO2/CuO nano-hybrid foam sensors were fabricated through thermal oxidation of Sn–Cu foam synthesized by electrochemical deposition, and their gas sensing properties were investigated. The macro-porous Sn–Cu foam was formed during electrodeposition, and its pore wall was composed of self-supported nano-sized dendrites. The annealing at 700 °C converted the Sn–Cu foam into the SnO2/CuO nano-hybrid foam with preserving the structural integrity and pore structure. The SnO2/CuO nano-hybrid foam sensor responded to the reducing gases such as H2, CO, NH3, NOx, CH5OH, and H2S, but the foam sensor exhibited two orders of magnitude higher gas response toward H2S. The enhanced sensitivity and selectivity toward H2S gas can be attributed to the formation of resistive p-CuO/n-SnO2 junction in nano-scale.