Cu–Pt/CrN Fuel Cell Gas Sensor Achieves ppb-Level H₂S Detection at Room Temperature

Fuel cell gas sensors have emerged as promising advanced sensing devices owing to their advantageous features of low power consumption and cost-effectiveness. However, commercially available Pt/C electrodes pose significant challenges in terms of stability and accurate detection of low concentrations of target gases. Here, we introduce an efficient Cu–Pt/CrN-based fuel cell gas sensor, designed specifically for the ultrasensitive detection of hydrogen sulfide (H2S) at room temperature. Compared to the commercial Pt/C sensor, the Cu–Pt/CrN sensor exhibits excellent sensitivity (0.26 μA/ppm), with an increase in the selectivity by a factor of 2.5, and demonstrates good stability over a 2 month period. The enhanced sensing performance can be attributed to the modulation of the electronic arrangement of Pt by Cu, resulting in an augmentation of H2S adsorption. The Cu–Pt/CrN fuel cell gas sensor provides an opportunity for detecting parts per billion-level H2S in various applications.