Constructing WS2/WO3-x heterostructured electrocatalyst enriched with oxygen vacancies for accelerated hydrogen evolution reaction.

H2 produced through hydrogen evolution reaction (HER) is a shining star in the field of clean energy. Significant efforts have been dedicated to develop efficient and stable electrocatalysts to reduce the energy barrier and accelerate the kinetics of Hydrogen evolution reaction (HER) under various environments. Herein, we propose a strategy to accelerate the kinetics of HER under acid and alkaline environments by combining heterostructure engineering with defect engineering. We have successfully synthesized a series of WS2/WO3-x heterostructured catalysts, accompanied with substantial oxygen vacancies using a two-step synthesis method. With the partially sulfurization of WO3-x, the heterojunction interface of WS2 and WO3-x was formed along with the appearance of oxygen vacancies, which can facilitate the migration of electrons. The heterostructured catalyst enriched with oxygen vacancies (defined as WS2/WO3-x-2) demonstrates superior HER performance in acidic and alkaline electrolytes. At a current density of 10 mA cm-2, the WS2/WO3-x-2 heterostructured catalyst manifests an overpotential of 120 mV in the acidic electrolytes and a slightly higher overpotential of 150 mV in an alkaline environment. The overpotentials offer an improvement compared to reported W-based catalysts in terms of HER performance. This work provides guiding significance on the design of heterostructured catalysts with promising performance for HER in acidic and alkaline environments.

Appraisal of the adsorption potential of novel modified gellan gum nanocomposite for the confiscation of methylene blue and malachite green.

In the present investigation a novel, environmentally affable and economical, modified gellan gum nanocomposite (MAA-g-GG/Ppy/MMT) was fabricated via free-radical polymerization for the liquid-phase mitigation of Methylene blue (MB) and Malachite green (MG) dyes. The innovation of this work is substantiated by the intentional combination of diverse materials, the strategic incorporation of polypyrrole for enhanced adsorption, and the thoughtful addition of MMT as a nanofiller to address mechanical strength and improve adsorption capacity. The physico-chemical facets of MAA-g-GG/Ppy/MMT and its interaction with the dye molecules were elucidated using FT-IR, SEM-EDX, BET, TEM, and XRD techniques. The optimum conditions for the sorption of MB and MG were deemed to be dosage (1.2 g/L for both dyes), contact time (50 min for both dyes), initial MG/MB concentration (MB = 40 mg/L & MG = 30 mg/L), and pH (MB = 10 & MG = 7). The Freundlich isotherm was identified as the most suitable model, as evidenced by the highest R2 value (∼0.999), indicating multilayer adsorption. The pseudo second-order model appraised the kinetic data. Thermodynamic findings revealed the adsorption process to be spontaneous, viable and exothermic which was ascertained by negative ∆H⸰ values (-22.8 kJ/mol for MB and -18.3 kJ/mol for MG). The substantial Langmuir adsorption capacity (Qm: MG =185.185; MB = 344.827) can be ascribed to the reason for strong interactions between MAA-g-GG/Ppy/MMT and dyes. The high reliability of MAA-g-GG/Ppy/MMT was determined by the regeneration studies that worked up to four cycles for both dyes. The real water (distilled water, tap water, and river water) samples spiked with MG/MB demonstrated a substantial uptake of dyes (>85 %) and the marginal influence of ionic strength on the adsorptive potential of MAA-g-GG/Ppy/MMT validated its efficacy for the decontamination of real effluents. The forces of attraction between the dyes and MAA-g-GG/Ppy/MMT included van der Waals, electrostatic forces of attraction, and π-π interaction. This green, economical, and viable MAA-g-GG/Ppy/MMT will prove to be an efficient adsorbent for the decontamination process of sequestration of dyes to achieve a sustainable environment.

Does interatrial communication affect post-operative course of children undergoing tetralogy of Fallot repair? Single centre retrospective cohort study: propensity score matching.

INTRODUCTION: During tetralogy of Fallot repair, leaving or even create an interatrial communication may facilitate post-operative course particularly with right ventricle restrictive physiology. The aim of our study is to assess the influence of atrial communication on post-operative course of tetralogy of Fallot repair. METHODS: Retrospectively, we studied all children who had tetralogy of Fallot repair (2003-2018). We divided them into two groups: tetralogy of Fallot repair with interatrial communication (TOFASD) group and tetralogy of Fallot repair with intact atrial septum (TOFIAS) group. We performed propensity match score for specific pre- or intra-operative variables and compared groups for post-operative outcome variables. Secondarily, we looked for right ventricle restrictive physiology incidence and influence of early repair performed before 3 months of age on post-operative course. RESULTS: One hundred and sixty children underwent tetralogy of Fallot repair including (93) cases of TOFIAS (58%) and (67) cases of TOFASD (42%). With propensity matching score, 52 patients from each group were compared. Post-operative course was indifferent in term of positive pressure ventilation time, vasoactive inotropic score, creatinine and lactic acid levels, duration and amount of chest drainage and length of intensive care unit and hospital stay. Right ventricle restrictive physiology occurred in 38% of patients with no effects on outcome. 12/104 patients (12%) with early repair needed longer pressure ventilation time (p = 0.003) and intensive care unit stay (p = 0.02). CONCLUSION: Leaving interatrial communication in tetralogy of Fallot repair did not affect post-operative course. As well, right ventricle restrictive physiology did not affect post-operative course. Infants undergoing early tetralogy of Fallot repair may require longer duration of positive pressure ventilation time and intensive care unit stay.