Cadmium sulfide in-situ derived heterostructure hybrids with tunable component ratio for highly sensitive and selective detection of ppb-level H2S

Herein, we reported cadmium sulfide derivatives pine needles-like CdS/CdO heterostructure hybrids synthesized by hydrothermal treatment and subsequent self-template oxidation approach. The component ratio of the CdS/CdO hybrids can be controlled specifically via tuning the annealing treatment protocol, and thereby giving rise to the optimization of morphology, electrical characteristics, and gas sensing properties of derived hybrids. As proof of concept, the pine needles-like CdS/CdO, which obtained after different annealing temperatures and durations, as sensitive material was employed to manufacture H2S gas sensors. The sensor based on CdS/CdO hybrids (400 degrees C & 1 h) exhibited high sensitivity (73.5 to 5 ppm), ppb-level limit of detection (10 ppb), and excellent selectivity regardless of the interference of other gases at optimal working temperature of 200 degrees C. Due to the abnormal resistance variation of n-type cadmium sulfide derived hybrids while contacting with H2S, the sensing mechanism mainly depends on the surface chemical conversion from oxide to sulfide. The pine needles-like hierarchical morphology provided an excellent scaffold for the carriers transportation and the growth of the CdO, which played a key role in resistance modulation both in air and target gas, resulting in the enhanced H2S sensing performance ultimately. (c) 2022 Elsevier Inc. All rights reserved.

Automated summary

In this study, pine needles-like CdS/CdO heterostructure hybrids were synthesized through hydrothermal treatment and subsequent self-template oxidation approach. The component ratio of the hybrids could be controlled by adjusting the annealing treatment protocol, leading to the optimization of morphology, electrical characteristics, and gas sensing properties. The resulting CdS/CdO hybrids were used as sensitive materials for H2S gas sensors, exhibiting high sensitivity, ppb-level limit of detection, and excellent selectivity.