Ir/Co/NiSe₂ Nanocages as High-Performance Electrocatalysts for Water Splitting and Sensors

In recent years, with the development of nanotechnology, there has been significant progress in the provision and functionalization of nanomaterials based on Ir nanostructures. It is possible to design different Ir-based nanoelectrolysts with improved performance and favorite structure using nanoengineering methods. In this study, porous Ir/Co/NiSe2 nanocages (NCs) were prepared using the sacrificial template approach, ion exchange strategy, and selenization under heat treatment. The designed Ir/Co/NiSe2 NCs were applied to modify the surface of the glassy carbon electrode (GCE) to use as an effective multifunctional electrocatalyst for the O2 and H2 evolution reactions (OER and HER) and glucose oxidation in an alkaline medium. The Ir/Co/NiSe2 NCs/GCE due to the using the advantages of a three-dimensional porous polymetallic hollow nanostructure, including providing high surface area and numerous electrochemical active sites, fast electron/mass transfer, high conductivity, and open channels for effective gas release in the OER and HER reactions, exhibits improved electrochemical performance. The Ir/Co/NiSe2 NCs/GCE delivered a current density of 100 mA cm–2 at 1.55 V for OER and −0.21 V for HER and determined glucose in the linear ranges of 100.0 nM to 2.0 mM and 2.0–17.0 mM with a limit of detection of 30 nM and sensitivity of 4375.8 and 477.7 μA mM–1 cm–2, respectively

Langmuir, Freundlich and D–R constants and correlation coefficients of TC adsorption on GO at different temperatures.

*<p>Dubinin–Radushkevich.</p

The pseudo-first-order (a) and the pseudo-second-order (b) kinetics model for adsorption of tetracycline on GO suspension (20.0 mg/L), pH = 3.6, T = 298, 308, 318 K.

<p>The pseudo-first-order (a) and the pseudo-second-order (b) kinetics model for adsorption of tetracycline on GO suspension (20.0 mg/L), pH = 3.6, T = 298, 308, 318 K.</p

Structure of graphene oxide (a), Structure of tetracycline and pKa values (b).

<p>Structure of graphene oxide (a), Structure of tetracycline and pKa values (b).</p

The UV–Vis absorption spectra of free TC, free GO and TC after adsorption on GO (GO-TC).

<p>The UV–Vis absorption spectra of free TC, free GO and TC after adsorption on GO (GO-TC).</p

FTIR spectra of free TC, free GO and TC after adsorption on GO (GO-TC).

<p>FTIR spectra of free TC, free GO and TC after adsorption on GO (GO-TC).</p

Variation of resultant force in the z direction <i>vs.</i> time.

<p>Variation of resultant force in the z direction <i>vs.</i> time.</p

Variation of z and x <i>vs</i>. time.

<p>Variation of z and x <i>vs</i>. time.</p

CV curve of tetracycline (1 mM, in phosphate buffer solution, 0.1 M, pH = 7) at 50 mV/s (a); CV curve of tetracycline (1 mM) at different scan rates: (from Bottom to up) 25, 50, 75, 100, 150, 200, 250, 300, 350, 400 mV/s (b); Observed dependence of peak current on the scan rate (c); Plot of variation of peak current with the logarithm of scan rate (d).

<p>CV curve of tetracycline (1 mM, in phosphate buffer solution, 0.1 M, pH = 7) at 50 mV/s (a); CV curve of tetracycline (1 mM) at different scan rates: (from Bottom to up) 25, 50, 75, 100, 150, 200, 250, 300, 350, 400 mV/s (b); Observed dependence of peak current on the scan rate (c); Plot of variation of peak current with the logarithm of scan rate (d).</p

Isotherm of TC (6.0–180.0 mg/L) adsorption on GO (20.0 mg/L) at different temperatures (298, 303, 308 K).

<p>Isotherm of TC (6.0–180.0 mg/L) adsorption on GO (20.0 mg/L) at different temperatures (298, 303, 308 K).</p