Platinum–Nickel Bimetallic Nanosphere–Ionic Liquid Interface for Electrochemical Oxygen and Hydrogen Sensing

Abstract

By exploiting the benefits of bimetallic platinum–nickel (Pt–Ni) alloy nanosphere and an ionic liquid (IL) (i.e., 1-butyl-1-methyl­pyrrolidinium bis­(trifluoro­methylsulfonyl)­imide (BmpyNTf2), an organic–inorganic hybrid interface of IL/Pt–Ni was designed and characterized for electrochemical sensing of oxygen and hydrogen gases for miniaturized electrochemical gas sensor development. The spherical Pt–Ni alloy nanoparticles (NPs) were synthesized through template-free, one-pot solvothermal method. The morphology, crystal structure, and chemical composition of Pt–Ni alloy NPs were thoroughly characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The obtained Pt–Ni alloy NPs were used to fabricate the planar sensor devices and tested for oxygen and hydrogen sensing. The oxygen-sensing performance of the resulting planar electrochemical sensor was investigated over a low concentration range of 500–5000 ppm of O2 at room temperature by using constant potential amperometry. The planar electrochemical sensor device exhibited a high sensitivity to O2 ((3.04 ± 0.18) × 10–5 mA cm–2 ppm–1) compared to commercial Pt/C-based sensor ((2.57 ± 0.22) × 10–5 mA cm–2 ppm–1). The planar electrochemical sensor device also showed good reproducibility and selectivity for oxygen detection during sensing tests. Moreover, the sensor device based on the obtained Pt–Ni alloy NPs was investigated for hydrogen detection with excellent analytical performance in hydrogen sensing. The outstanding gas sensing properties were attributed to unique interface properties and highly efficient catalytic reaction of gas species of oxygen and hydrogen at the interface of IL/Pt–Ni alloy NPs. This work demonstrated that the integration of Pt–Ni alloy NPs with ILs enabled beneficial electrode interface for O2 and H2 gases sensing with high sensitivity, rapid gas response, and superior reproducibility based on a novel planar electrochemical sensor platform.

The Critical Impacts of Ligands on Heterogeneous Nanocatalysis: A Review

“…Wang and co-workers also adopted a similar method for constructing a metal–IL interface, which largely improved the electrocatalytic activity of ethanol oxidation . In other reports, the ligands themselves were treated as supports, especially for some polymers, ILs, and dendrimers. − Because there are more lone electron pairs inside the ligands (or supports), the electronic interactions between the metals and the ligands (or supports) are stronger, which largely influences the catalytic activity. For example, Han and co-workers fabricated dendrimer-capped AgCo bimetallic NPs by directly using poly­(amidoamine) (PAMAM) as the support and capping ligand.…”

Double-Layer Carbon Encapsulated Co Particles Combined with Ionic Liquid for Enhancing Electrochemical Detection of Oxygen

“…With these factors taken into consideration, ionic liquids (ILs) are given more and more attention for their outstanding characteristics including high ionic conductivity, thermal stability, nonvolatility, and low vapor pressure, as well as wide electrochemical windows. − These characteristics made them suitable to be widely employed in fields of electrochemistry such as electrosynthesis, electrochemical supercapacitors, and sodium batteries, especially acting as both electrolytes and solvents simultaneously for electrochemical (gas) sensors. − There have been works reported on the O 2 reduction behavior in multiple ionic liquids in diverse concentrations, verifying the feasibility of ionic liquids acting as solvent and electrolyte simultaneously for electrochemical oxygen detectors. , Although the restrictions of traditional sensors can be avoided by utilization of ionic liquid electrolytes, challenges involving low viscosity and weak response yet remain for ionic liquid sensors. Strategies were hence developed such as modifying the ionic liquid electrolyte by introducing electroactive materials, which has recently become the preferable method.…”

Gasochromic Hydrogen Sensors: Fundamentals, Recent Advances, and Perspectives

“…Several categories of nanomaterials can react with H 2 and produce sensing signals, such as electrochemical, (18) chemoresistive, (19,20) optical, (21,22) mechanical, (23) and other signals, (24,25) which can be used to develop hydrogen sensors. Therefore, there have been numerous studies on hydrogen sensors.…”