Dataset Information

PH dependent electro-oxidation of arsenite on gold surface: Relative kinetics and sensitivity.

ABSTRACT: A detailed kinetic investigation of As(III) oxidation was performed on gold surface within pH between ∼3.0 and ∼9.0. It was found that the As(III) oxidation on the gold surface follows a purely adsorption-controlled process irrespective of pH. The evaluated adsorption equilibrium constant decreased from 3.21 × 10⁵ to 1.61 × 10⁵ mol L^-1 for acidic to basic medium, which implies the strong affinity of the arsenic species in the acidic medium. Besides, the estimation of Gibbs free energy revealed that an acidic medium promotes arsenic oxidation on gold surface. In mechanistic aspect, the oxidation reaction adopts a stepwise pathway for acidic medium and a concerted pathway for neutral and basic medium. From the substantial kinetic evaluation, it is established that a conducive and compatible environment for the oxidation of arsenic was found in an acidic medium rather than a basic or neutral medium on gold surface. Besides, in sensitivity concern, neutral and highly acidic medium is quite favourable for the arsenite oxidation on gold surface.

SUBMITTER: Ahsan M

PROVIDER: S-EPMC10023909 | biostudies-literature | 2023 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

pH dependent electro-oxidation of arsenite on gold surface: Relative kinetics and sensitivity.

Ahsan Mohebul M Bin Mukhlish Muhammad Zobayer MZ Khatun Nazia N Hasnat Mohammad A MA

Heliyon 20230306 3

A detailed kinetic investigation of As(III) oxidation was performed on gold surface within pH between ∼3.0 and ∼9.0. It was found that the As(III) oxidation on the gold surface follows a purely adsorption-controlled process irrespective of pH. The evaluated adsorption equilibrium constant decreased from 3.21 × 105 to 1.61 × 105 mol L-1 for acidic to basic medium, which implies the strong affinity of the arsenic species in the acidic medium. Besides, the estimatio ...[more]

PMID: 36942233

Similar Datasets

Project description:As a vital process for solar fuel synthesis, water oxidation remains a challenging reaction to perform using durable and cost-effective systems. Despite decades of intense research, our understanding of the detailed processes involved is still limited, particularly under photochemical conditions. Recent research has shown that the overall kinetics of water oxidation by a molecular dyad depends on the coordination between photocharge generation and the subsequent chemical steps. This work explores similar effects of heterogeneous solar water oxidation systems. By varying a key variable, the reaction temperature, we discovered distinctly different behaviors on two model systems, TiO2 and Fe2O3. TiO2 exhibited a monotonically increasing water oxidation performance with rising temperature across the entire applied potential range, between 0.1 and 1.5 V vs the reversible hydrogen electrode (RHE). In contrast, Fe2O3 showed increased performance with increasing temperature at high applied potentials (>1.2 V vs RHE) but decreased performance at low applied potentials (<1.2 V vs RHE). This decrease in performance with temperature on Fe2O3 was attributed to an increased level of electron-hole recombination, as confirmed by intensity-modulated photocurrent spectroscopy (IMPS). The origin of the differing temperature dependences on TiO2 and Fe2O3 was further ascribed to their different surface chemical kinetics. These results highlight the chemical nature of charge recombination in photoelectrochemical (PEC) systems, where surface electrons recombine with holes stored in surface chemical species. They also indicate that PEC kinetics are not constrained by a single rate-determining chemical step, highlighting the importance of an integrated approach to studying such systems. Moreover, the results suggest that for practical solar water splitting devices higher temperatures are not always beneficial for reaction rates, especially under low driving force conditions.

Dataset Information

PH dependent electro-oxidation of arsenite on gold surface: Relative kinetics and sensitivity.

Publications

pH dependent electro-oxidation of arsenite on gold surface: Relative kinetics and sensitivity.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets