Fast response detection of H2S by CuO-doped SnO2 films prepared by electrodeposition and oxidization at low temperature

Fast response detection of H2S by CuO-doped SnO2 films prepared was prepared by a simple two-step process: electrodeposition from aqueous solutions of SnCl2 and CuCl2, and oxidization at 600 °C. The phase constitution and morphology of the CuO-doped SnO2 films were characterized by X-ray diffraction and scanning electron microscopy. In all cases, a polycrystalline porous film of SnO2 was the product, with the CuO deposited on the individual SnO2 particles. Two types of CuO-doped SnO2 films with different microstructures were obtained via control of oxidation time: nanosized CuO dotted island doped SnO2 and ultra-uniform, porous, and thin CuO film coated SnO2. The sensor response of the CuO doped SnO2 films to H2S gas at 50–300 ppm was investigated within the temperature range of 25–125 °C. Both of the CuO-doped SnO2 films show fast response and recovery properties. The response time of the ultra-uniform, porous, and thin CuO coated SnO2 to H2S gas at 50 ppm was 34 s at 100 °C, and its corresponding recovery time was about 1/3 of the response time.