Tailoring the electrochemical properties of 2D-hBN via physical linear defects: physicochemical, computational and electrochemical characterisation

Monolayer hexagonal-boron nitride films (2D-hBN) are typically reported within the literature to be electrochemically inactive due to their considerable band gap (ca. 5.2–5.8 eV). It is demonstrated herein that introducing physical linear defects (PLDs) upon the basal plane surface of 2D-hBN gives rise to electrochemically useful signatures. The reason for this transformation from insulator to semiconductor (inferred from physicochemical and computational characterisation) is likely due to full hydrogenation and oxygen passivation of the boron and/or nitrogen at edge sites. This results in a decrease in the band gap (from ca. 6.11 to 2.36/2.84 eV; theoretical calculated values, for the fully hydrogenated oxygen passivation at the N or B respectively). The 2D-hBN films are shown to be tailored through the introduction of PLDs, with the electrochemical behaviour dependent upon the surface coverage of edge plane-sites/defects, which is correlated with electrochemical performance towards redox probes (hexaammineruthenium(III) chloride and Fe2+/3+) and the hydrogen evolution reaction. This manuscript de-convolutes, for the first time, the fundamental electron transfer properties of 2D-hBN, demonstrating that through implementation of PLDs, one can beneficially tailor the electrochemical properties of this nanomateria

Potentiometric and surface topography studies of new carbon-paste sensors for determination of thiamine in Egyptian multivitamin ampoules

We report here for the first time two potentiometric carbon-paste sensors for determination of thiamine chloride hydrochloride in aqueous solutions. The proposed sensors use the ion-pair of thiamine with tetraphenylborate as an electro-active species and dibutyl phthalate (sensor I) or o-nitrophenyloctyl ether (sensor II) as solvent mediators. The effect of solvent mediator was studied using dibutyl phthalate, o-nitrophenyloctyl ether, ethylhexyl adipate, dioctyl phthalate, tricresyl phosphate and paraffin oil. The slopes of the calibration graphs are 29.49 ± 0.24 and 29.60 ± 0.15 mV/decade for sensors (I) and (II), respectively. The sensors are able to detect down to 5.25 × 10−6 and 3.57 × 10−6 for (I) and (II), respectively. Both sensors show reasonable thermal stability and fast response time. The selectivity coefficients obtained from the matched potential method indicate high selectivity of the proposed sensors toward thiamine over commonly interfering cations. Sensor (I) has a lifetime of only 1–2 days; however, sensor (II) remains usable for up to one month. Analytical applications to pure solutions and Egyptian multivitamin ampoules show excellent recovery values ranging from 97.92 to 103.72% and 97.21 to 102.19% for sensors (I) and (II), respectively. Moreover, the precision and reproducibility of the sensors are indicated from the low values of %RSD of five replicate measurements. In addition, the surface topography of the sensors was studied using scanning electron microscopy to investigate the effect of chemical modification on the surface structure

Exploring the electrochemical performance of graphite and graphene paste electrodes composed of varying lateral flake sizes

From Crossref via Jisc Publications Router.Version: VoRFunder: Ramsay Memorial Fellowships Trust, University College London, Grant no: N/A, FundRef: 10.13039/501100000685Funder: British Council, Grant no: British Council Institutional Link grant (No. 172726574), FundRef: 10.13039/50110000030

Novel Set of Highly Substituted Bis-Pyridines: Synthesis, Molecular Docking and Drug-Resistant Antibacterial Profile - Supplementry_Information

Mass spectra, 1H NMR, 13C NMR, IR spectrum of compounds 3a - 7h  </p