Differential pulse voltammetry (DPV) using gallium oxide nanoparticles/carbon paste electrode (Ga2O3/CPE) was utilized for the simultaneous detection of Pb2+, Cd2+ and Hg2+ ions. Ga2O3NPs were chemically synthesized and fully characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Through the assay optimization, electrochemical screening of different nanomaterials was carried out using the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in order to determine the best electrode modifier that will be implemented for the present assay. Consequently, various parameters such as electrode matrix composition, electrolyte, deposition potential, and deposition time were optimized and discussed. Accordingly, the newly developed sensing platform showed a wide dynamic linear range of 0.3–80 µM with detection limits (LODs) of 84, 88 and 130 nM for Pb2+, Cd2+ and Hg2+ ions, respectively. While the corresponding limit of quantification (LOQ) values were 280, 320 and 450 nM. Sensors selectivity was investigated towards different non-targeting metal ions, whereas no obvious cross-reactivity was obtained. Eventually, applications on real samples were performed, while excellent recoveries for the multiple metal ions were successfully achieved.

Application of aniline derivative semiconductor nanopolymer and its Au composite for H2 generation and dye removal were investigated. Electrochemical polymerization of poly-3-methylaniline (P3MA) on ITO glass was carried out for acid medium. Au nanoparticles with crystal sizes of 15 and 30 nm were sputter coated on the surface. Chemical structure of the polymer and its composite was characterized using FTIR, XRD, 1HNMR, SEM, and UV-Vis. All function groups were confirmed using FTIR analyses. XRD confirmed the formation of nanopolymer with a crystal size of ~15 nm. SEM confirmed the formation of smooth lamellar surface feature with a <20 nm nanoporous structure. Porosity and particle sizes increases with Au coating, confirmed using the modeling Image J program. Optical analysis also demonstrated that the strength of P3MA absorption peaks increases with rising Au coating time, in which the bandgap values changed from 1.64 to 1.63 eV for 15 and 30 nm Au, respectively. The photoelectrode ITO/PMT/30 nm Au was applied for H2 generation and dye removal. The current density (Jph) values were -0.3 and -1.6 mA.cm-2 in the absence and presence of the Congo red dye, respectively. The incident photon-to-current conversion efficiency (IPCE%) for the electrode was 2.3 at 390 nm. The activation energy (Ea) was 31.49 KJ mol-1. The enthalpy (∆H*) and entropy (∆S*) values were 114.49 and 160.46 JK-1 mol-1, respectively. A simple mechanism for the H2 generation and dye removal is mentioned

This study provides H2 gas as a renewable energy source from sewage water splitting reaction using a PMT/Au photocathode. So, this study has a dual benefit for hydrogen generation; at the same time, it removes the contaminations of sewage water. The preparation of the PMT is carried out through the polymerization process from an acid medium. Then, the Au sputter was carried out using the sputter device under different times (1 and 2 min) for PMT/Au-1 min and PMT/Au-2min, respectively. The complete analyses confirm the chemical structure, such as XRD, FTIR, HNMR, SEM, and Vis-UV optical analyses. The prepared electrode PMT/Au is used for the hydrogen generation reaction using Na2S2O3 or sewage water as an electrolyte. The PMT crystalline size is 15 nm. The incident photon to current efficiency (IPCE) efficiency increases from 2.3 to 3.6% (at 390 nm), and the number of H2 moles increases from 8.4 to 33.1 mmol h−1 cm−2 for using Na2S2O3 and sewage water as electrolyte, respectively. Moreover, all the thermodynamic parameters, such as activation energy (Ea), enthalpy (ΔH*), and entropy (ΔS*), were calculated; additionally, a simple mechanism is mentioned for the water-splitting reaction.

No abstract