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

Abstract

Electrospun carbon nanofibers (CNF) with surfaceanchored 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 tracelevel hydrogen gas for real time applications.

Integrated co-axial electrospinning for a single-step production of 1D aligned bimetallic carbon fibers@AuNPs–PtNPs/NiNPs–PtNPs towards H2 detection

“…The higher intensity of ID/IG peak for co-axial CFs@AuNPs-PtNPs may be due to the SERS enhancement upon introduction of plasmonic Au in the CFs based bimetallic nanosystem. 20,30 The structural and morphological analysis of the co-axial electrospun CFs based bimetallic nanosystem were further executed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. The electric-field lines in the gap between Cu electrodes are drawn towards the electrode edges as seen in the electric field profile in Figure 4a.…”

“…These PAN fibers were converted into co-axial CFs@PtNPs based nanosystems via dual-step thermal method comprising of stabilization and carbonization. 20 The stabilization and carbonization of PAN fibers were executed in a tubular furnace containing a Quartz tube. The nanofibers undergo heat treatment in air and N2 atmosphere in the furnace at controlled temperature with a rate of 2°C/min and 3°C/min retained for Please do not adjust margins Please do not adjust margins 1h.…”

“…Our earlier work have explored the bimetallic Au-Pt NPs over CFs synthesized via wet chemical route to sense H2 gas. 20 The CFs with AuNPs-PtNPs upgraded the response time of the sensor in comparison with the monometallic PtNPs on CFs. Though CFs@AuNPs-PtNPs displayed exceptional H2 sensing properties, cost reduction, but, the multi-step fabrication process was found to be its limitations for mass production.…”

Advances in Doped ZnO Nanostructures for Gas Sensor

“…With the rapid development of economy and industrialization, the emission of harmful gases has a significant impact on public safety, air quality and human health [1a,b,c,d] . Reliable methods to facilitate real‐time monitoring of toxic gases are urgently needed.…”

“…ZnO based gas sensors possess the advantages of high response, excellent electrical performance and long‐term stability [13] . However, the practical application of ZnO nanomaterials in gas sensing is limited due to its low selectivity, high operating temperature and poor resistance to humidity [1b,12b,14] . In the past few decades, the crystal structure, electron concentration and surface dynamics of ZnO materials have been changed by different synthesis methods, doping, modification, UV irradiation and coating [6a,15a,b,c] .…”