Ni–Co alloy nanostructures anchored on mesoporous silica nanoparticles for non-enzymatic glucose sensor applications

Abstract

Uniform sized Ni-Co alloy nanoparticles were effectively confined over the active channels of mesoporous silica nanoparticles (MSN) using a simple chemical reduction method, and the resultant nanostructures exhibited a spherical configuration with a mean diameter of 5 nm. The face-centered cubic (fcc) crystalline structure of Ni and Ni-Co alloy nanoparticles and the amorphous structure of MSN matrix were identified from the diffraction patterns. The MSN supported catalysts were exploited as electrochemical probes for the detection of glucose, and the controlled morphology, smaller particle size, uniform dispersion and active surface of the Ni-Co alloy nanoparticles improved the excellent electrocatalytic activity of MSN/Ni-Co toward the electrooxidation of glucose. The MSN/Ni-Co nanocomposite exhibited good analytical performance for glucose detection, with a linear response ranging from 0.001 to 5.0 mM, a low detection limit of 0.39 mM and a high sensitivity of 536.62 mA mM À1 cm À2 . The results of the performed experiments also demonstrated the good reproducibility, long-term stability and high selectivity of the fabricated sensors without the influence of interference from other oxidizable species, which may represent a technically sound and economical new avenue in nonenzymatic glucose sensor applications.

Ni-Co bimetal nanowires filled multiwalled carbon nanotubes for the highly sensitive and selective non-enzymatic glucose sensor applications

“…The observed reflection planes of Ni-Co bimetal in MWCNT/Ni-Co (Fig. 3i-c) are similar to the characteristic planes of Ni nanoparticles in the MWCNT/Ni, owing to the close lattice parameters of both Ni(3.523 °A) and Co(3.544 °A) (JCDPS 15-0806,Co;04-0850,Ni)3143. The mean crystallite sizes of Ni and Ni-Co nanowires filled in the MWCNTs are estimated to be 13 nm, which are in good agreement with the obtained TEM images.…”

“…In addition to the carbonaceous peaks, MWCNT/Ni exhibited the significant diffraction peaks at 2θ = 44.5, 51.9 and 76.3° (Fig. 3i-b), which can be indexed to the (111), (200) and (220) crystal planes of fcc structure of Ni, ensuring the presence of metallic Ni in MWCNT/Ni3142. The observed reflection planes of Ni-Co bimetal in MWCNT/Ni-Co (Fig.…”

“…Ag/AgCl, specifying the involvement of Ni(II)/Ni(III) redox couple toward the glucose electrooxidation. The analyte glucose (C 6 H 12 O 6 ) was oxidized into gluconolactone (C 6 H 10 O 6 ) through Ni(III) in an alkaline medium, as evidenced from the increased Ipa values314548. The electrooxidation of glucose at MWCNT/Co/GCE was achieved via the Co(III)/Co(IV) redox couple at 0.53 V vs .…”

“…The diameter of catalyst matrix is closely correlated with the diameter of MWCNTs, leading to the interest on well dispersed nanosized catalyst systems with the narrower size distribution25. Hence, a keen focus has been paid toward the active substrate supported catalysts and the metal-substrate interactions play a significant role in determining the growth of MWCNTs, which directed the exploitation of various catalyst supports including Zeolite26, Al 2 O 3 27, SiO 2 28, TiO 2 29, CaCO 3 30, mesoporous silica nanoparticles (MSN) etc., Among the aforesaid active supports, MSN is considered as the ideal choice for the synthesis of MWCNTs, owing to its uniform and tailorablemesopores, large surface area, narrow pore size distribution, ordered pore structure, biocompatibility etc.,31. The inactive siliceous properties construct the ideal interaction with the active metal nanoparticles along with the less interruption by the metal-support interaction32.…”

Nickel-oxide multiwall carbon-nanotube/reduced graphene oxide a ternary composite for enzyme-free glucose sensing

“…4 Several previous reports on this topic successfully employed the enzyme glucose oxidase (GODx), which catalyses the oxidation of glucose to gluconolactone. 5 However, enzyme based biosensors suffer from several drawbacks such as poor stability, tedious enzyme immobilization procedures and higher cost etc.. 6,7 Therefore, there is a greater demand to develop the enzyme-free glucose sensors based on the direct electro oxidation without using an enzyme or mediators. However, selecting the accurate catalyst for direct glucose oxidation is an important step in the development of enzyme-free glucose sensors.…”