Abstract
Hydrogen (H2) gas is an emerging clean energy carrier, but it poses significant safety risks because it is highly flammable and can explode easily, at low concentrations (4%). Existing H2 sensors struggle with high operating temperatures, higher response/recovery times and poor selectivity. This work presents an optimally designed PdrGO composite able to detect H2 gas at concentrations below 100 ppm (sub-explosive) with much faster response time. The sensing performance of the PdrGO composite, synthesized using a simple one-pot hydrothermal technique, is optimized by varying rGO concentration. Uniform distribution and successful synthesis of Pd nanoparticles over the exfoliated rGO sheets was confirmed using advanced characterizations such as FESEM, HRTEM, EDX, XRD, FTIR, XPS, BET and RAMAN. The PdrGO-100 sensor showed the best performance at 100 ppm H2, which is below explosive limit, the sensor showed 21% response and a response/recovery time of 13/23 s at 100 °C. A LoD of 6.3 ppm was obtained for the sensor, which is representing a significant improvement over existing rGO based sensors. The sensor is able to detect H2 gas precisely in the presence of other gases (H2S, CO, NO2, NO and NH3) and its performance is linear across the range 12 ppm to 100 ppm. Thus, this work presents a promising framework for detecting trace leaks at early stages, offering a viable alternative to methods that rely on large gas volumes (>10,000 ppm) of H2 gas.
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•Pd-rGO nanocomposite is synthesized using a simple, one-pot hydrothermal method.•Pd-rGO-100 sensor is tested with 12–100 ppm H2 within temperature range 25–150 °C.•Sensor shows a response of 21% with a LoD of 6.3 ppm.•Sensor establishes a response and recovery times of 13 s and 23 s, respectively.•Sensor demonstrates degradation of 4.7% over a continuous 30-day testing period.