Unraveling Hydrogen Adsorption Kinetics of Bimetallic Au-Pt Nanoisland-Functionalized Carbon Nanofibers for Room-Temperature Gas Sensor Applications

Electrospun carbon nanofibers (CNF) with surface-anchored bimetallic gold-platinum nanoislands (CNFs@Au-Pt NIs) have been effectively developed by electrospinning and chemical reduction methods, and its enhanced trace-level hydrogen gas sensing characteristics at room temperature have been explored. Structural and morphological properties of the CNFs@platinum NIs (CNFs@Pt NIs) and CNFs@gold-platinum NIs (CNFs@Au-Pt NIs) have been characterized using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy analyses, which showed the successful formation of bimetallic Au-Pt NIs homogeneously distributed over the surface of CNFs. The bimetallic Au-Pt NIs on CNFs provide superior hydrogen gas sensing properties toward wide range detection of hydrogen gas from 0.01 to 4% under ambient conditions. Desorption of hydrogen from the nanohybrids without any delay is possible as the chemisorbed hydrogen on Pt has been compensated with the integration of Au on CNFs leading to rapid response and recovery time. Adsorption kinetics studies indicate that the adsorption of hydrogen occurs on active Au-Pt bimetallic sites because of the work function differences leading to changes in the resistance. In situ Raman spectroscopic analysis revealed the interaction of hydrogen (H-2) gas with the catalytic active NIs at room temperature, and a plausible mechanism has been proposed. This bimetallic catalyst functionalized CNFs can be considered as a potential candidate for the development of high-performance gas sensors with fast recovery and amplified response toward trace-level hydrogen gas for real time applications.