Delafossite CuGaO2 nanomaterial-based room temperature H2S selective gas sensor

Abstract

To minimize harmful gas exposure and enable early disease diagnoses in low-resource settings, it is crucial to create an H₂S gas sensor that can detect low ppb levels at room temperature (RT). H₂S is both a widespread environmental pollutant and a significant breath biomarker for several diseases. Nevertheless, the development of portable inhaled gas sensors faces significant obstacles in achieving extremely sensitive and quick detection of H₂S gas at low temperatures, specifically at the ppm level. In order to tackle this problem, we demonstrate delafossite CuGaO₂ as a highly effective material deposited by RF sputtering for H₂S sensing at RT. We connected two sensors in parallel, one with high selectivity towards H₂S at RT and another with a high response working at 50 °C from the same materials. The delafossite CuGaO₂ film shows the most significant response of 10.7% at 50 ppm of H₂S, capable of detecting concentrations as low as 54.3 ppb at RT. The response time was ∼55 s, while the recovery time was ∼135 s with a high selectivity towards H₂S. Increasing the sensor temperature to 50 °C, an immediate escalation in the response by more than twofold around 25.03% with slight disturbance in the selectivity was observed, with LOD of 12.68 ppb and response and recovery times of ∼66 s and 258 s, respectively. The CuGaO₂ sensor demonstrated acceptable resistance/response variation towards different humidity, repeatability, long-term stability, and minimal change in cross-selectivity at both temperatures. This detection method at RT and 50 °C will assist in the development of cutting-edge manufacturing procedures that have the potential to enhance gas sensor technology. This will allow manufacturers to make a portable sensor that is suitable for real-time sensing applications.