Hydrogen sulfide is one of the most common toxic contaminants frequently utilized in various fields, including the oil, gas, waste treatment, and paper industries. Even trace amounts of H₂S gas are extremely toxic to many organisms, such as human respiratory and nerve systems. Generally, it is recommended that the acceptable ambient levels of H₂S for a healthy condition are in the range of 20 -100 ppb.

A research group led by Professor FANG Xiaodong and MENG Gang from the Anhui Institute of Optics and Fine Mechanics (AIOFM) of the Hefei Institutes of Physical Science explored a novel H₂S sensor which is made of a new fabricated material (Sr_0.6Bi_0.305)₂Bi₂O₇/ZnO. This sensor, abbreviated as SBO/ZnO, possesses excellent H₂S sensing performances.

"We use facile one-step hydrothermal method to develop the material," said CHANG Junqing, a student who joined the research, "it boasts high response, low limit of detection, good selectivity and long-term stability."

In this research, scientists found that when the concentration of H₂S was 10 ppm and the sensitivity reached 107.6. Besides, the limit of the detection was lowered to 20 ppb.

Such enhanced response is contributed to the increased oxygen vacancy and the reversible sulfurization-desulfurization reaction. The material has the merits of low operation temperature of 75 °C and weak humidity dependence.

This novel heterostructural sensor paves the way for the practical monitoring of trace H₂S pollutants in diverse workplaces including petroleum and natural gas industries.

These works were financially supported by the projects of the International Cooperation, the National Natural Science Foundation of China, and the CAS-JSPS Joint Research Projects, etc.

Fig. (a) selectivity, (b) long-term stability, (c)humidity dependence. (Image by CHANG Junqing)