Exploiting the synergistic catalytic effects of CoPi nanostructures on Zr-doped highly ordered TiO2 nanotubes for efficient solar water oxidation

Photoelectrochemical (PEC) catalysis offers promising strategies for sustainable development. This study demonstrated the synergistic catalytic behavior of ZrO2 and a cobalt phosphate on anodized TiO2 nanotubes (TNTs), which significantly enhanced the PEC performance for visible-light-driven water splitting reactions. The sequential addition of ZrO2/CoPi-decorated TNTs was performed via electrodeposition and photoassisted electrodeposition. The substitution of Zr4+ by Ti4 can lead to the creation of oxygen vacancies, enabling electron trapping, reducing charge recombination, and thereby enhancing the charge transfer efficiency. Further, in the case of TNTs/ZrO2/CoPi photoanode, the CoPi WOC functioned as a hole-transfer relay to promote the water-splitting reaction. Specifically, incorporating ZrO2/CoPi rushes the surface reaction kinetics of TNTs and considerably improves charge transfer efficiency (ηCT = 90%), photocurrent density (0.86 mA/cm2 at 1.23 VRHE) and durability were obtained. Further, the mechanistic examination by impedance measurements showed the enhanced charge transfer, and surface conductivity for prepared materials. The proposed method can be widely used to develop electrodes made of other materials to produce solar fuels

Enhancing the Optical Absorption and Interfacial Properties of BiVO4 with Ag3PO4 Nanoparticles for Efficient Water Splitting

Photoelectrochemical water splitting using semiconductor materials has emerged as a promising approach to produce hydrogen (H2) from renewable resources such as sunlight and water. In the present study, Ag3PO4 nanoparticles were electrodeposited on BiVO4 photoanodes for water splitting. A remarkable water oxidation photocurrent of 2.3 mA·cm–2 at 1.23 V versus reversible hydrogen electrode with ∼100% Faradaic efficiency was obtained, which constitutes a notable increase compared to the pristine BiVO4 photoanode. It is demonstrated that the enhancement of optical absorption (above-band gap absorbance) and the decrease of surface losses after the optimized deposition of Ag/Ag3PO4 nanoparticles are responsible for this notable performance. Remarkably, this heterostructure shows promising stability, demonstrating 25% decrease of photocurrent after 24 h continuous operation. This approach may open new avenues for technologically exploitable water oxidation photoanodes based on metal oxides

Photoelectrochemical performance of strontium titanium oxynitride photo-activated with cobalt phosphate nanoparticles for oxidation of alkaline water

Photoelectrochemical (PEC) solar water splitting is favourable for transforming solar energy into sustainable hydrogen fuel using semiconductor electrodes. Perovskite-type oxynitrides are attractive photocatalysts for this application due to their visible light absorption features and stability. Herein, strontium titanium oxynitride (STON) containing anion vacancies of SrTi(O,N)3−δ was prepared via solid phase synthesis and assembled as a photoelectrode by electrophoretic deposition, and their morphological and optical properties and PEC performance for alkaline water oxidation are investigated. Further, cobalt-phosphate (CoPi)-based co-catalyst was photo-deposited over the surface of the STON electrode to boost the PEC efficiency. A photocurrent density of ~138 μA/cm at 1.25 V versus RHE was achieved for CoPi/STON electrodes in presence of a sulfite hole scavenger which is approximately a four-fold enhancement compared to the pristine electrode. The observed PEC enrichment is mainly due to the improved kinetics of oxygen evolution because of the CoPi co-catalyst and the reduced surface recombination of the photogenerated carriers. Moreover, the CoPi modification over perovskite-type oxynitrides provides a new dimension for developing efficient and highly stable photoanodes in solar-assisted water-splitting reactions

Review on Carbon Dioxide Utilization for Cycloaddition of Epoxides by Ionic Liquid-Modified Hybrid Catalysts: Effect of Influential Parameters and Mechanisms Insight

The storage, utilization, and control of the greenhouse (CO2) gas is a topic of interest for researchers in academia and society. The present review article is dedicating to cover the overall role of ionic liquid-modified hybrid materials in cycloaddition reactions. Special emphasis is on the synthesis of various cyclic carbonate using ionic liquid-based modified catalysts. Catalytic activity studies have discussed with respect to process conditions and their effects on conversion and product selectivity for the reaction of cycloaddition of CO2 with styrene oxide. The reaction temperature and the partial pressure of CO2 have found to play a key role in cyclic carbonate formation. The role of other influential parameter (solvent effect) is also discussed for the conversion of cyclic/aromatic oxides to polycarbonate production. Our own research work that deals with ionic liquid-based halide-modified mesoporous catalyst (MCM-41 type) derived from rice husk waste has also been discussed. Finally, the role of carbon dioxide activation and ring-opening mechanisms involved in the cyclic carbonate product formation from CO2 have been discussed

Review on Carbon Nanotube Varieties for Healthcare Application: Effect of Preparation Methods and Mechanism Insight

Many potential uses of carbon nanotubes (CNT) in various sectors have created an urge to assess their diverse range of properties pertaining to various applications like catalysis, biosensor, and antimicrobial activity. Increasing studies on the biosensor and antibacterial activity of CNT have prompted tremendous interest in the utilization of the carbon-based nanostructured material as an alternative to currently existing antibiotics. However, the study of bactericidal aspects of this nanomaterial is relatively new and hence the deeper understanding of the various physicochemical characteristics and antimicrobial nature of CNT is extremely wanted. This review covers the effect of framework substitution and explains the understanding of membrane disintegration and oxidative stresses upon nanomaterials for antimicrobial activity. The present article has also reviewed effect of preparation nanoparticle deposition and framework modification on carbon nanotube structure. The recent research on graphene-modified nanomaterials for biosensor applications related to healthcare/clinical applications have also been discussed. Major physicochemical contributing factors such as size, functionalization, high surface area, and aggregation features of CNT assisting in the bacterial killing have nicely been outlined. Hence, the present review explains the supporting information related with Single and multi-walled carbon nanotube and summarized the advantages of functionalized carbon nanotube/graphene-based nanostructured carbon-based materials towards protection and reduction of bacterial/viral infections in the healthcare sector

Facile synthesis of Fe3O4 nanorod decorated reduced graphene oxide (RGO) for supercapacitor application

The development of electrode materials capable of delivering high electrochemical performance is a major challenge. Herein, we demonstrate a facile approach for the synthesis of rod-shaped Fe3O4 nanostructures anchored on the reduced graphene oxide (RGO) surface and its application as an active electrode material for supercapacitors. The RGO-Fe3O4 nanocomposite was prepared by the spontaneous deposition of the rod-like FeOOH nanostructure onto the self-reduced GO surface followed by a thermal annealing process. The physical characterizations demonstrate the decoration of the rod-like Fe3O4 nanostructure over the RGO surface. Morphology analysis demonstrates that Fe3O4 nanorods with an average size of 150 nm are distributed over the RGO surface. The surface area analysis demonstrates that the as-synthesized RGO-Fe3O4 nanorod nanocomposite has 186 m(2) g(-1) specific surface area, which is higher compared to the Fe3O4 nanorods. As an active electrode material, the RGO-Fe3O4 nanocomposite shows excellent electrochemical performance compared to Fe3O4 nanorods. On the RGO-Fe3O4 nanocomposite based electrode a specific capacity of 315 C g(-1) was observed at 5 A g(-1) current density. Additionally, the RGO-Fe3O4 nanocomposite based electrode displayed excellent cycling stability with 95% specific capacity retention after 2000 cycles. The electrochemical results demonstrates that the RGO-Fe3O4 nanocomposite could be a promising material for energy conversion and storage.</p

Fabrication of Cost-Effective Dye-Sensitized Solar Cells Using Sheet-Like CoS2 Films and Phthaloylchitosan-Based Gel-Polymer Electrolyte

Platinum-free counter electrodes (CE) were developed for use in efficient and cost-effective energy conversion devices, such as dye-sensitized solar cells (DSSCs). Electrochemical deposition of CoS2 on fluorine-doped tin oxide (FTO) formed a hierarchical sheet-like structured CoS2 thin film. This film was engaged as a cost-effective platinum-free and high-efficiency CE for DSSCs. High stability was achieved using a phthaloychitosan-based gel-polymer electrolyte as the redox electrolyte. The electrocatalytic performance of the sheet-like CoS2 film was analyzed by electrochemical impedance spectroscopy and cyclic voltammetry. The film displayed improved electrocatalytic behavior that can be credited to a low charge-transfer resistance at the CE/electrolyte boundary and improved exchange between triiodide and iodide ions. The fabricated DSSCs with a phthaloychitosan-based gel-polymer electrolyte and sheet-like CoS2 CE had a power conversion efficiency (PCE, η) of 7.29% with a fill factor (FF) of 0.64, Jsc of 17.51 mA/cm2, and a Voc of 0.65 V, which was analogous to that of Pt CE (η = 7.82%). The high PCE of the sheet-like CoS2 CE arises from the enhanced FF and Jsc, which can be attributed to the abundant active electrocatalytic sites and enhanced interfacial charge-transfer by the well-organized surface structure