Sulfur-Rich N-Doped Co9S8 Catalyst for Highly Efficient and Durable Overall Water Electrolysis Application

Facile template-free controllable growth of freestanding polyhedron-like CoS onto microporous Ni foam with three-dimensional architecture via a mild hydrothermal technique is reported. The as-obtained CoS catalyst phase was first tailored to N-Co9S8 (nitrogen doped Co9S8), and its inherent reaction kinetics and conductivity were then enhanced through sulfur incorporation via a hydrothermal process. The electrochemical performance of the pristine CoS and a sulfur-enriched N-Co9S8 (S, N-Co9S8) electrode in alkaline 1.0 M KOH was examined. The optimized polyhedral S, N-Co9S8 structured catalyst exhibits significantly enhanced electrocatalytic activity for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). As a result, low overpotentials of 244 and -92 mV is required to achieve the current density of 10 mA cm(-2) for the OER and HER, respectively. Furthermore, when the polyhedral S, N-Co9S8 catalyst was employed as a bifunctional catalyst in a two-electrode electrolyzer cell exhibiting a cell voltage of 1.549 V at 10 mA cm(-2) and demonstrates excellent long-term (50 hrs.) chronopotentiometric electrolysis at various current rate, reveals excellent bifunctional OER and HER activities at different applied current densities. The superior OER and HER activities of the S, N-Co9S8 catalyst is result of the improved electronic conductivity and enhanced intrinsic reaction kinetics, which led to the enhanced electrocatalytically active sites after the incorporation of heteroatoms in the catalyst structure

Precursor silanization assisted synthesis and optical tuning of dual-phase perovskite nanocrystals embedded in silica matrix with high environmental stability

Ligand-assisted re-precipitation (LARP) is one of the most practicing techniques for synthesizing colloidal nanocrystals (NCs). But due to its fast reaction kinetics, it offers limited synthesis control. In the present study, we report a novel, precursor silanization-based room temperature technique unveiling slow crystallization of Cs4PbBr6/CsPbBr3 dual-phase nanocrystals (DPNCs) protected with a dense silica cloud-like matrix. Unlike conventional LARP, we can observe the tuneable optical bandgap of the DPNCs as a function of reaction time because of the slow reaction kinetics. The as-synthesized DPNCs exhibit a high photoluminescence quantum yield (PLQY) of 76% with ultrahigh stability while retaining similar to 100% of their initial PLQY in an ambient environment with a relative humidity of 55% for more than 1 year. DPNCs demonstrates ambient photostability of 560 h, and water stability of 25 days. This interesting precursor silanization technique developed here can be extended for the synthesis of other nanomaterials. (c) 2022 Elsevier Inc. All rights reserved

Copper cobalt tin sulphide (Cu2CoSnS4) anodes synthesised using a chemical route for stable and efficient rechargeable lithium-ion batteries

In everyday life superior lithium-ion batteries (LIB) with fast charging ability have become a valuable asset. The LIB performance of anode composite copper cobalt tin sulphide (Cu2CoSnS4; CCTS) electrodes, which were fabricated using a simple and easy hydrothermal method, was investigated. The electrochemical charge storage performance of the CCTS anode demonstrated sustainability, high-rate capability and efficiency. The CCTS anode exhibited a first discharge capacity of 914.5 mAhg−1 and an average specific capacity of 198.7 mAhg−1 in consecutive cycles at a current density of 0.1 Ag−1. It had a capacity retention of ~62.0% and a coulombic efficiency of more than 83% after over 100 cycles, demonstrating its excellent cycling performance and reversibility. It can be an alternative anode to other established electrode materials for real battery applications

Optimal rule-of-thumb design of NiFeMo layered double hydroxide nanoflakes for highly efficient and durable overall water-splitting at large currents

Because hydrogen is an ideal energy source, electrocatalysts for water splitting that employ transition metal hydroxides rather than expensive precious metals to produce molecular hydrogen have been extensively investigated. In the present study, Ni<INF>x</INF>Fe<INF>y</INF>Mo<INF>z</INF> layered double hydroxide (LDH) electrocatalysts fabricated via a simple hydrothermal technique for overall water splitting in an alkaline medium are reported. The best-performing Ni<INF>x</INF>Fe<INF>y</INF>Mo<INF>z</INF> LDH catalysts require overpotentials of 200 and 86 mV to reach a current density of 10 mA cm<SUP>-2</SUP> for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. Theoretical analysis indicates that the Mo-rich O<INF>Mo<INF>2</INF>Fe</INF> and Fe-rich O<INF>Fe<INF>3</INF></INF> active sites strongly activate the HER and OER, respectively. More importantly, a water electrolyzer containing the best-performing Ni<INF>x</INF>Fe<INF>y</INF>Mo<INF>z</INF> LDH catalysts as the anode and cathode is able to reach an industrially relevant current density of 1000 mA cm<SUP>-2</SUP> at a cell voltage of only 2.1 V. The electrolyzer exhibits outstanding stability at very high current densities of 0.1, 0.5 and 1 A cm<SUP>-2</SUP> for overall water splitting over 90 hours of continuous operation, which is superior to state-of-the-art devices based on precious metals. The overall water-splitting activity presented here demonstrates the practical potential of the proposed electrocatalysts as inexpensive options for use in water electrolyzers

The Therapeutic Effect of Human Embryonic Stem Cell-Derived Multipotent Mesenchymal Stem Cells on Chemical-Induced Cystitis in Rats

Purpose To evaluate the therapeutic effect of human embryonic stem cell (hESC)-derived multipotent mesenchymal stem cells (M-MSCs) on ketamine-induced cystitis (KC) in rats. Methods To induce KC, 10-week-old female rats were injected with 25-mg/kg ketamine hydrochloride twice weekly for 12 weeks. In the sham group, phosphate buffered saline (PBS) was injected instead of ketamine. One week after the final injection of ketamine, the indicated doses (0.25, 0.5, and 1×106 cells) of M-MSCs (KC+M-MSC group) or PBS vehicle (KC group) were directly injected into the bladder wall. One week after M-MSC injection, the therapeutic outcomes were evaluated via cystometry, histological analyses, and measurement of gene expression. Next, we compared the efficacy of M-MSCs at a low dose (1×105 cells) to that of an identical dose of adult bone marrow (BM)-derived MSCs. Results Rats in the KC group exhibited increased voiding frequency and reduced bladder capacity compared to rats of the sham group. However, these parameters recovered after transplantation of M-MSCs at all doses tested. KC bladders exhibited markedly increased mast cell infiltration, apoptosis, and tissue fibrosis. Administration of M-MSCs significantly reversed these characteristic histological alterations. Gene expression analyses indicated that several genes associated with tissue fibrosis were markedly upregulated in KC bladders. However the expression of these genes was significantly suppressed by the administration of M-MSCs. Importantly, M-MSCs ameliorated bladder deterioration in KC rats after injection of a low dose (1×105) of cells, at which point BM-derived MSCs did not substantially improve bladder function. Conclusions This study demonstrates for the first time the therapeutic efficacy of hESC-derived M-MSCs on KC in rats. M-MSCs restored bladder function more effectively than did BM-derived MSCs, protecting against abnormal changes including mast cell infiltration, apoptosis and fibrotic damage