Highly Sensitive, Flexible H2 Gas Sensors Based on Less Platinum Bimetallic Ni–Pt Nanocatalyst-Functionalized Carbon Nanofibers

Flexible electronic gas sensors working at room temperature have acquired enormous attention in recent years due to their suitability to be integrated into various wearable electronic products. In this investigation, we have demonstrated a H2 gas sensor using less platinum bimetallic nickel–platinum nanocatalyst-functionalized carbon nanofibers (CNFs@Ni–Pt) fabricated on a flexible platform. The flexible CNF@Ni–Pt sensor showed only a negligible decrease in response during mechanical stress under flat (21%) and bent (17%) states after several bending cycles owing to the high aspect ratio of the carbon nanofiber network, which helps us to indulge a long bending path. Moreover, the flexible CNF@Ni–Pt sensor showed superior sensor response (50%) toward H2 with outstanding selectivity toward other interfering gases. In addition, hydrogen adsorption kinetic studies performed on flexible CNF@Ni–Pt sensors indicated comparable theoretically calculated (0.42) and experimental (0.49) rate constant values. In situ Raman spectroscopy analysis aided in unraveling the H2 interaction with the catalytically active Ni–Pt sites anchoring on the surface of CNFs, and a plausible sensing mechanism could be predicted. Flexible, less platinum CNF@Ni–Pt sensors can find wider applications in the fields of flexible electronics, biomedical, and environmental monitoring.