To achieve good living standards, it is critical to make high-performance toxic gas sensing devices for public safety, environmental pollutant control, industrial operations, and other applications. For this purpose, we demonstrate CuO anchored SnO2 nanostructures for H2S gas sensors. The selectivity was improved by anchoring with CuO for a total 60 s duration at four equal consecutive cycles to achieve good selectivity towards H2S molecules. The pristine CuO shows instability and metallic behaviour when it is exposed to H2S for a longer time. Furthermore, the proposed gas sensor shows good selectivity toward H2S as compared to other gases H2, NO2, CO2, and NH3. The sensing response was measured at around 69 % at the optimal operating temperature of 150°C. It is observed that CuS formation has better selectivity as compared to pristine SnO2 and a slight improvement in sensitivity is observed. As a result, a promising strategy for designing and producing good-performance H2S gas sensors would be to CuO anchor on SnO2 nanostructures. The proposed sensors may be integrated with IoT platforms and used for the detection of H2S in the sewer line and leak detection in the petroleum industry. Display omitted •SnO2 thin film was anchored with CuO at different time duration using RF sputtering for H2S gas sensing.•The sensor exhibits higher sensing response of 69 % at 150 ºC for 100 ppm of H2S with a LoD of 1 ppm.•Comparative analysis was performed for H2S gas detection for both SnO2 and CuO/SnO2 based sensors.•Excellent selectivity and slight improved sensitivity was observed with CuO/SnO2 based gas sensor.