The quest for sustainable and clean energy sources has intensified research on the Hydrogen Evolution Reaction (HER) in recent decades. In this study, we present a novel Ce-doped TiO2 catalyst synthesized through the sol-gel method, showcasing its potential as a superior electrocatalyst for HER in an acidic medium. Comprehensive characterization through X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Energy dispersive X-ray (EDX), and Raman spectroscopy confirms the successful formation of the catalyst. Electrocatalytic performance evaluation, including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and Tafel analysis, demonstrates that GCE-5wt.%CeTiO2 outperforms bare GCE, as well as Ce and TiO2-based electrodes. Kinetic investigations reveal a Tafel slope of 105 mV dec-1, indicating the Volmer step as the rate-determining step. The onset potential for HER at GCE-5wt.%CeTiO2 is -0.16 V vs. RHE, close to the platinum electrode. Notably, the catalyst exhibits a low overpotential of 401 mV to achieve a current density of 10 mA cm−2 with an impressive 95% Faradaic efficiency. Furthermore, the catalyst demonstrates outstanding durability, maintaining a negligible increase in overpotential during a 14-hour chronoamperometry test. These results have far-reaching implications for the development of cost-effective and efficient electrocatalysts for hydrogen production.

Design the low-cost, sustainable, and greener 3c-DES MegPAc catalyst as a synthetic tool. MegPAc serves the purpose to synthesize of pyrazolo[5,1-b]quinazoline-3-carboxylates and also worked profoundly in a gram-scale synthesis as well. Practically water is the only green waste though protocols demonstrated an admirable green chemistry credentials.

Abstract

An unprecedented meglumine-based three-component deep eutectic solvent (3c-DES) (MegPAc) was synthesized using meglumine, p-toluenesulfonic acid (PTSA), and acetic acid as a renewable, and non-toxic solvent. The exploitation of the MegPAc as an eco-friendly reaction media to construct a selective and sensitive small organic molecular sensing probe, namely, pyrazolo[5,1-b]quinazoline-3-carboxylates (PQCs) was executed. Captivatingly, the MegPAc served the dual role of solvent and catalyst, and it delivered the title components with 69–94 % yields within 67–150 minutes. Furthermore, a UV-visible study unfolds the selective detection of Cu²⁺ ions with our synthetic probe 4 ba and resulted in hypsochromic shift due to electrostatic interactions. Additionally, ¹H NMR titration study and density functional theory (DFT) calculations were performed to attest the binding mechanism of sensing probe 4 ba and Cu²⁺ ions. Worthy of mention, this protocol unveils the efficacy of meglumine-based 3c-DES for the first time as a bio-renewable system to synthesize the PQCs.

This study employs a one–step solvothermal approach to incorporate ferrocene (Fc) into nickel sulfide nanostructures, revealing exceptional electrocatalytic performance with an overpotential of 290 mV@10 mA cm⁻², surpassing traditional nickel sulfide catalysts. Fc−NiS demonstrates superior charge transfer characteristics, attributed to ferrocene‘s effect on electrical conductivity. With remarkable stability over 25 hours, Fc−NiS emerges as a promising non-noble-based catalyst for sustainable hydrogen production.

Abstract

Enhanced electrocatalysts that are cost-effective, durable, and derived from abundant resources are imperative for developing efficient and sustainable electrochemical water–splitting systems to produce hydrogen. Therefore, the design and development of non–noble–based catalysts with more environmentally sustainable alternatives in efficient alkaline electrolyzers are important. This work reports ferrocene (Fc)-incorporated nickel sulfide nanostructured electrocatalysts (Fc−NiS) using a one–step facile solvothermal method for water–splitting reactions. Fc−NiS exhibited exceptional electrocatalytic activity under highly alkaline conditions, evident from its peak current density of 345 mA cm⁻², surpassing the 153 mA cm⁻² achieved by the pristine nickel sulfide (NiS) catalysts. Introducing ferrocene enhances electrical conductivity and facilitates charge transfer during water–splitting reactions, owing to the inclusion of iron metal. Fc−NiS exhibits a very small overpotential of 290 mV at 10 mA cm⁻² and a Tafel slope of 50.46 mV dec⁻¹, indicating its superior charge transfer characteristics for the three–electron transfer process involved in water splitting. This outstanding electrocatalytic performance is due to the synergistic effects embedded within the nanoscale architecture of Fc−NiS. Furthermore, the Fc−NiS catalyst also shows a stable response for the water–splitting reactions. It maintains a steady current density with an 87% retention rate for 25 hours of continuous operation, indicating its robustness and potential for prolonged electrolysis processes.

A comparative crystallographic study of Cd(II)/Hg(II) complexes of isomeric purine rare tautomers and subsequent nanoring formation investigated by molecular dynamics simulations and transmission electron microscopy.

Abstract

We report three complexes of Cd^II and Hg^II with two purine rare tautomers, N9-(pyridin-2-ylmethyl)-N ⁶-methoxyadenine, L1 and N7-(pyridin-2-ylmethyl)-N ⁶-methoxyadenine, L2, highlighting diverse crystallographic signatures exhibited by them. Influence of substituents, binding sites, steric effects and metal salts on the different modes of binding enabled an insight into metal-nucleobase interactions. L1 interacted with two and three equivalents of Cd(NO₃)₂.4H₂O and HgCl₂, respectively, while L2 interacted with two equivalents of HgCl₂, altogether leading to three different complexes (1 [C₄₈H₄₈Cd₆N₃₄O₅₀], 2 [C₁₂H₁₂Cl₄Hg₂N₆O] and 3 [C₁₂H₁₂Cl₂HgN₆O]) possessing varied dimensionality and stabilising interactions. The photoluminescent properties of these coordination frameworks have also been probed. Notably, nanoring-like structures were obtained, as a result of self-assembly of 3 when investigated by transmission electron microscopy, additionally supported by molecular dynamics simulations.

A NIR-driven Janus Cu₂O/Au nanomotor had been constructed to explore the synergistical therapeutic effect on hepatoma carcinoma cells. The asymmetric Au modification causes uneven heating on both sides of the Cu₂O/Au nanomotor, resulting in autonomous motion from high to low temperature, actively targeting hepatocellular carcinoma cells. Under the synergistic effects of photothermal therapy, photodynamic therapy and Cu₂O′s own nanotoxicity, Cu₂O/Au nanomotors exhibit highly effective killing effect on liver cancer cells.

Abstract

We presented a NIR-driven Janus Cu₂O/Au nanomotor. The nanomotor has a truncated octahedral structure. By asymmetric Au evaporation, the light response range of Cu₂O nanomotor is extended to near-infrared range, and the speed of Cu₂O/Au nanomotors under NIR is significantly increased. In promoting apoptosis of hepatocellular carcinoma, except the nanotoxicity of Cu₂O itself, the Au layer enhances the photothermal properties, allowing Cu₂O/Au nanomotors to induce apoptosis in hepatocellular carcinoma cells by heating them. On the other hand, a Schottky barrier formed at the interface of Cu₂O and Au, preventing the recombination of electrons, which makes more electrons react with biomolecules to produce toxic ROS to kill hepatocellular cells. The killing rate of hepatocellular carcinoma cells reached 87 % by the combined effect of nanotoxicity inhibition of proliferation and photothermal & photodynamic therapy (PTT & PDT). Nanomotors in combination with multiple approaches are explored as a new treatment to tumor in this article.

Single phase Mn-doped CdS thin films were successfully synthesized by the chemical bath deposition. Different morphologies like nano-cubes, nanoflakes, nano-worms, and nanosheets were obtained under different deposition conditions. The optimized Mn-doped CdS exhibited better photoelectrochemical (PEC) performance for oxygen evolution reaction (OER) than pure CdS films.

Abstract

Doping conventional materials with a second element is an exciting strategy for enhancing catalytic performance via electronic structure modifications. Herein, Mn-doped CdS thin films were successfully synthesized with the aid of the chemical bath deposition (CBD) by varying the pH value (8, 10, and 12) and the surfactant amount (20, 40, 60 mg). Different morphologies like nano-cubes, nanoflakes, nano-worms, and nanosheets were obtained under different deposition conditions. The optimized Mn-doped CdS synthesized at pH=8 exhibited better photoelectrochemical (PEC) performance for oxygen evolution reaction (OER) than pure CdS films, with a maximum photocurrent density of 300 μA/cm² at an external potential of 0.5 V, under sunlight illumination. The observed performance is attributed to the successful Mn doping, porosity, high surface area, and nanosphere morphology.

In this study, we investigate the mechanism of CCR to CH₄ over Al₂O₃-supported Ni−Ca DFMs. Various spectroscopic analyses, including time-resolved in situ XRD and XAS, were conducted during CO₂ capture and the subsequent H₂-reduction steps.

Abstract

Carbon dioxide capture and reduction (CCR) to CH₄ using dual-functional materials (DFMs) have recently attracted significant attention as a promising strategy for carbon capture and utilization. In this study, we investigate the mechanism of CCR to CH₄ over Al₂O₃-supported Ni−Ca DFMs (Ni−Ca/Al₂O₃) under cyclic feeds of model combustion exhaust (2.5 % CO₂+0 or 10 % O₂/N₂) and H₂ at 500 °C. Various spectroscopic analyses, including time-resolved in situ X-ray diffraction and X-ray absorption spectroscopy, were conducted during CO₂ capture and the subsequent H₂-reduction steps. Based on these analyses, we propose a mechanism of CCR to CH₄ over Ni−Ca based DFMs. During the CO₂ capture step, the Ni⁰ species underwent complete oxidation in the presence of O₂ to yield NiO. Subsequently, CO₂ was captured through the interaction between the CaO surface and CO₂, resulting in the formation of CaCO₃ layers on the CaO particles. When the gas flow was switched to H₂, NiO was partially to provide Ni⁰ sites, which acted as active sites for H₂-reduction of the adjacent CaCO₃ layers to yield CaO and gas-phase products, CH₄ and H₂O.

We analyze examples of enhanced catalysis based on interparticle (reverse) hydrogen spillover. Simple physical mixtures of powdered catalysts containing metal catalysts of H₂ dissociation/recombination and solid catalysts with active sites for substrate activation significantly enhance catalytic reactions, including aromatic hydrogenation, CO₂ methanation, deoxydehydration of polyols, aromatization of lower paraffins, and direct coupling of benzene and alkanes.

Abstract

Interparticle hydrogen spillover is the phenomenon of H migration over different catalyst particles, which should be a physical mixture of at least two solid catalysts. In this review, we analyze examples of enhanced catalysis based on interparticle (reverse) hydrogen spillover. Simple physical mixtures of powdered catalysts containing metal catalysts of H₂ dissociation/recombination and solid catalysts with active sites for substrate activation significantly enhance catalytic reactions. These reactions include aromatic hydrogenation, CO₂ methanation, and the deoxydehydration of polyols, aromatization of lower paraffins, and direct coupling of benzene and alkanes. The acceleration effect and proposed reaction pathway of each example involving interparticle (reverse) hydrogen spillover are summarized. Simple reaction systems comprising physical mixtures of at least two powdery solid catalysts should enable unique catalysis in the future with the aid of interparticle (reverse) hydrogen spillover.

A novel and efficient palladium-catalyzed cascad cyclization/alkenylation of ynone oximes with various vinylsilane agents for the assembly of synthetically valuable isoxazolyl vinylsilane derivative has been accomplished. Under the optimized conditions, a wide array of ynone oximes can be efficiently converted into the isoxazolyl vinylsilanes in moderate to good yields with eminent functional group compatibility.

Abstract

A palladium-catalyzed cascade cyclization/alkenylation for the assembly of synthetically valuable isoxazolyl vinylsilane derivative has been accomplished. Easily accessible ynone oximes, and available vinylsilane agents were used as the reaction starting materials This protocol features broad substrate scope, good functional group tolerance, and good step- and atom-economy. Remarkably, this approach provides a new approach for the construction of structurally diverse isoxazolyl-containing vinylsilanes with high molecular complexity, showing a promising application in synthetic and pharmaceutical chemistry.

A simple acyclic molecule binds sulfate strongly (K _a>10⁴ M⁻¹) in a competitive 4 : 1 d₆-acetone:D₂O mixture. The molecule also reacts readily with BF₄ ⁻ and BPh₄ ⁻ to give zwitterions containing an anion tetrahedral boronate centre. These zwitterions were characterised crystallographically.

Abstract

A simple dihydroxy isoquinolinium molecule (3⁺ ) was prepared by a modification of a literature procedure. Interestingly, during optimisation of the synthesis a small amount of the natural product pseudopalmatine was isolated, and characterised for the first time by X-ray crystallography. Compound 3⁺ contains a catechol motif and positive charge on the same scaffold and was found to be a potent anion receptor, binding sulfate strongly in 8 : 2 d₆-acetone:D₂O and 7 : 3 d₆-acetone:D₂O (K _a>10⁴ and 2,100 M⁻¹, respectively). Unsurprisingly, chloride binding was much weaker, even in the less polar solvent mixture 9 : 1 d₆-acetone:D₂O. The sulfate binding is remarkably strong for such a simple molecule, however anion binding studies were complicated by the tendency of the molecule to react with BPh₄ ⁻ or BF₄ ⁻ species during anion metathesis reactions. This gave two unusual zwitterions containing tetrahedral boronate centres, which were both characterised by X-ray crystallography.