February 29, 2024

“Killing Two Birds With One Stone” – Hydrophobic Molecular Sieve Developed for Humidity-Resistance Hydrogen Sulfide Sensor

By Hefei Institutes of Physical Science, Chinese Academy of Sciences
March 28, 2023

In order to resolve these problems, researchers vaporized a hydrophobic and semipermeable membrane of polydimethylsiloxane (PDMS) on the Pt single-atom anchored CuCrO2 by the thermal evaporation technique.
Zhang Ruofan, first author of the paper, explained the biofunctional function of PDMS as “eliminating 2 birds with one stone.”
PDMS had hydrophobic nature. It could successfully isolate the invasion of water vapor in the environment, damaged the impact of ecological humidity on the sensing unit, and substantially improved the long-lasting stability of the sensor in a damp environment.
On the other side, the micropores in the PDMS membrane might effectively block methyl mercaptan (CH3SH) particles whose diameter was slightly larger than H2S. It acted as a “molecular screen”, even more improving the selectivity of the sensing unit for H2S.
The humidity-resistant H2S sensing unit based upon PDMS-coated CuCrO2 had a low operating temperature (100 ℃), high reaction (approximately 151 for 5 ppm H2S at 50% relative humidity), high selectivity, and excellent long-lasting stability, which laid a crucial structure for the practical application of H2S sensing unit in petrochemical, gas, and other fields.
” Bifunctional function of PDMS membrane in creating humidity-tolerant H2S chemiresistors with high selectivity” by Ruofan Zhang, Zanhong Deng, Junqing Chang, Zhongyao Zhao, Shimao Wang and Gang Meng, 16 January 2023, Chemical Communications.DOI: 10.1039/ D2CC05880D.
” Pt-Anchored CuCrO2 for Low-Temperature-Operating High-Performance H2S Chemiresistors” by Ruofan Zhang, Zanhong Deng, Lei Shi, Mahesh Kumar, Junqing Chang, Shimao Wang, Xiaodong Fang, Wei Tong and Gang Meng, 20 May 2022, ACS Applied Materials & & Interfaces.DOI: 10.1021/ acsami.2 c00619.

H2S is a colorless, flammable, explosive, extremely corrosive, and highly hazardous gas, which widely exists in semi-closed and high-humidity locations. Some oxides including zno, delafossite, and cuo have a high reaction to H2S in dry air, however the humidity tends to interfere with the response of sensing units. In addition, H2S is an extremely corrosive gas, and its corrosiveness increases with the boost of humidity.

Bifunctional role of PDMS membrane in creating H2S sensors– humidity resistant and selectivity improved. Credit: Zhang Ruofan
A group of researchers under the management of Prof. Meng Gang from the Hefei Institutes of Physical Science (HFIPS), Chinese Academy of Sciences (CAS), checked out the usage of polydimethylsiloxane (PDMS) in establishing high-performance, humidity-resistant hydrogen sulfide (H2S) sensors, supplying a course towards the useful application of H2S chemiresistors in damp air environments.
The outcomes were released in ACS Applied Materials && Interfaces and Chemical Communication, respectively.
Some oxides including cuo, zno, and delafossite have a high reaction to H2S in dry air, however the humidity tends to interfere with the action of sensors. In addition, H2S is a highly corrosive gas, and its corrosiveness increases with the boost of humidity.