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.