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Abstract We investigated the role of metal atomization and solvent decomposition into reductive species and carbon clusters in the phase formation of transition‐metal carbides (TMCs; namely, Co3C, Fe3C, TiC, and MoC) by pulsed laser ablation of Co, Fe, Ti, and Mo metals in acetone. The interaction between carbon s–p‐orbitals and metal d‐orbitals causes a redistribution of valence structure through charge transfer, leading to the formation of surface defects as observed by X‐ray photoelectron spectroscopy. These defects influence the evolved TMCs, making them effective for hydrogen and oxygen evolution reactions (HER and OER) in an alkaline medium. Co3C with more oxygen affinity promoted CoO(OH) intermediates, and the electrochemical surface oxidation to Co3O4 was captured via in situ/operando electrochemical Raman probes, increasing the number of active sites for OER activity. MoC with more d‐vacancies exhibits strong hydrogen binding, promoting HER kinetics, whereas Fe3C and TiC with more defect states to trap charge carriers may hinder both OER and HER activities. The results show that the assembled membrane‐less electrolyzer with Co3C∥Co3C and MoC∥MoC electrodes requires ~2.01 and 1.99 V, respectively, to deliver a 10 mA cm−2 with excellent electrochemical and structural stability. In addition, the ascertained pulsed laser synthesis mechanism and unit‐cell packing relations will open up sustainable pathways for obtaining highly stable electrocatalysts for electrolyzers.

Eliminating harmful organic pollutants from contaminated water remains an urgent problem to be solved. Taking Rhodamine B (RhB) as a representative organic water pollutant we sought to design a facile and scalable synthesis of a BiFeO3/CeVO4 (BFO/CVO) nanocomposite catalyst for the degradation of organic pollutant under visible light. BFO nanorods and CVO nanoparticles were fabricated using single-step hydrothermal routes and the resulting materials could be easily combined using a simple wet-chemical precipitation method. From the morphological studies, pure BiFeO3 and CeVO4 revealed the 1D-nanorod and 0D-nanoparticles, respectively. For the BFO/CVO composite, 0D-nanoparticles were well attached on the 1D-nanorods of BiFeO3. Also, the 10 % BFO/CVO composite provided efficient photodegradation efficiency (92 %) of RhB with 0.0225 min−1 rate constant. Furthermore, the obtained photocatalyst had a low band gap energy value (2.01 eV) and photoluminescence intensity when compared to pure BFO and CVO under visible light illumination. The radical scavenging experiments proposed that the •OH acted a substantial role in the RhB decomposition pathway. The optimized BFO/CVO composite photocatalyst exhibits superior recyclability and photostability. The superior photocatalytic action of the 10 % BFO/CVO composite could be explained by the development of a heterojunction among BFO and CVO where electrons can migrate at the BFO/CVO interface. These results imply that BiFeO3/CeVO4 composites are suitable photocatalysts for the elimination of organic toxins from water.

Electrocatalytic urea oxidation reaction (UOR) has emerged as a promising alternative to the anodic oxygen evolution reaction (OER) in water electrolysis. However, UOR faces challenges like slow kinetics, high energy barriers, and a complex mechanism, necessitating the development of efficient electrocatalysts. Herein, a rapid method is proposed for synthesizing Mo‐doped Ni/NiO (Ni/MNO) nanocomposite as a highly effective UOR electrocatalyst. Mo doping oxidizes Ni2+ to Ni3+, creating abundant active sites for UOR. The Ni/MNO catalyst exhibits remarkable activity for both OER and UOR due to Mo doping, structural modulation, increased active sites, and the presence of Ni3+ ions. Optimized Ni/MNO‐10 shows a low OER overpotential of 280 mV and a UOR working potential of 1.37 V versus reversible hydrogen electrode at 10 mA cm−2, with exceptional stability over 12 h of continuous electrolysis. Notably, urea‐assisted water splitting requires only 1.45 V for 10 mA cm−2, significantly less than the overall water splitting voltage (1.65 V), indicating energy‐efficient hydrogen production. Moreover, the Ni/MNO catalyst exhibits outstanding long‐term stability. This work presents a rapid and effective approach to synthesizing cost‐effective and efficient electrocatalysts for clean energy production and wastewater treatment.

Abstract The dynamic surface reconstruction of electrodes is a legible sign to understand the deep phase‐transition mechanistic and electrocatalytic origin during the oxygen evolution reaction (OER). Herein, we report a dual‐laser pulse‐patterned heterointerface of α‐Co(OH)2 and reduced graphene oxide (rGO) nanosheets via pulsed laser irradiation in liquid (PLIL) to accelerate OER kinetics. α‐Co(OH)2 was formed from the OH− ions generated during the PLIL of GO at neutral pH. Co2+ modulation in tetrahedral coordination sites benefits as an electrophilic surface for water oxidation. Few d‐vacancies in Co2+ increase its affinity toward oxygen, lowering the energy barrier and generating many CoOOH and CoO2 active sites. rGO with an ordered π‐conjugated system aids the surface adsorption of OOH*, O*, and OH* during OER. α‐Co(OH)2 surface phase‐transition and OER mechanistic steps occurred via phase‐reconstruction to CoOOH and CoO2 reactive intermediates, uncovered using in situ electrochemical–Raman spectroscopy. Our findings in the dual‐laser pulse strategy and the surface reconstruction correlation in active OER catalysts pave the path for paramount in multiple energy technologies.

In this work, we explored the in-situ reaction modeling of the molecular self-aggregation of methylene blue (MB), which is a cationic thiazine dye, in different solvents via a container-less acoustic levitator by floating of a single droplet. Our in-situ spectroscopic study revealed that the dimer essentially has a sandwich structural geometry with a deviation from parallel stacking and horizontal arrangements in the molecular planes. The real time conversion of the monomer in MB into a dimer and their dynamics in water and ethanol media were monitored using a free-standing acoustic levitator droplet system. The absorption spectra revealed changes in the two resolved peaks (monomer and dimer) and orderliness when water and ethanol were used as the media. Interestingly, the enhancement in the dimerization of MB could be attributed to droplet evaporation, which is difficult to observe in typical reactor containers. Moreover, acidic protonation resulted in a change in the aggregation orientation direction of the MB molecules, forming an unusual J-aggregation. Theoretical DFT calculations revealed that MB underwent typical H-aggregation and J-aggregation in the different solvent environments, and their orientations well matched the spectroscopic data.

Pulsed laser method uses a laser as an energy source to produce diverse materials in various environments for the reactions of photo- and electrocatalytic applications.

Acoustic levitation is a distinctive and versatile tool for levitating and processing free-standing single droplets and particles. Liquid droplets suspended in an acoustic standing wave provide container-free environments for understanding chemical reactions by avoiding boundary effects and solid surfaces. We attempted to use this strategy for the production of well-dispersed uniform catalytic nanomaterials in an ultraclean confined area without the addition of external reducing agents or surfactants. In this study, we report on the synthesis of gold and silver nanoparticles (NPs) via acoustic levitation coupled with pulsed laser irradiation (PLI). In situ UV–Visible and Raman spectroscopic techniques were performed to monitor the formation and growth of gold and silver NPs. The PLI was used for the photoreduction of targeted metal ions present in the levitated droplets to generate metal NPs. Additionally, the cavitation effect and bubble movement accelerate the nucleation and decrease the size of NPs. The synthesized Au NPs with ∼ 5 nm size showed excellent catalytic behavior towards the conversion of 4-nitrophenol to 4-aminophenol. This study may open a new door for synthesizing various functional nanocatalysts and for achieving new chemical reactions in suspended droplets.

Abstract Binding energies of different nitrile solvents and their utilization for CuCN formation were investigated through quantum chemical calculations. A pulsed laser ablation in liquid (PLAL) method for CuCN synthesis was developed herein. Initially, the interaction between the pulsed laser and the Cu-target generated Cu-ions and electrons at the point of contact. The laser beam also exhibited sufficient energy to dissociate the bonds of the respective solvents. In the case of acetonitrile, the oxidized Cu-ions bonded with CN− to produce CuCN with a cube-like surface structure. Other nitrile solvents generated spherically-shaped Cu@graphitic carbon (Cu@GC) nanoparticles. Thus, the production of CuCN was favorable only in acetonitrile due to the availability of the cyano group immediately after the fragmentation of acetonitrile (CH3 + and CN−) under PLAL. Conversely, propionitrile and butyronitrile released large amounts of hydrocarbons, which deposited on Cu NPs surface to form GC layers. Following the encapsulation of Cu NPs with carbon shells, further interaction with the cyano group was not possible. Subsequently, theoretical study on the binding energies of nitrile solvents was confirmed by highly correlated basic sets of B3LYP and MP2 which results were consistent with the experimental outcomes. The findings obtained herein could be utilized for the development of novel metal–polymer materials.

The title compound, C22H22N2O4S2, was synthesized by the reaction of 1,4,5,8-naphthalenetetracarboxylic dianhydride with 3-(methylsulfanyl)propylamine. The whole molecule is generated by an inversion operation of the asymmetric unit. This molecule has an anti form with the terminal methylthiopropyl groups above and below the aromatic diimide plane, where four intramolecular C—H...O and C—H...S hydrogen bonds are present and the O...H...S angle is 100.8°. DFT calculations revealed slight differences between the solid state and gas phase structures. In the crystal, C—H...O and C—H...S hydrogen bonds link the molecules into chains along the [2\overline20] direction. adjacent chains are interconnected by π–π interactions, forming a two-dimensional network parallel to the (001) plane. Each two-dimensional layer is further packed in an ABAB sequence along the c-axis direction. Hirshfeld surface analysis shows that van der Waals interactions make important contributions to the intermolecular contacts. The most important contacts found in the Hirshfeld surface analysis are H...H (44.2%), H...O/O...H (18.2%), H...C/C...H (14.4%), and H...S/S...H (10.2%).

In this study, Pd-graphene quantum dot (Pd-GQD) catalysts were prepared by depositing Pd nanoparticles onto functionalized GQD surfaces, and their morphology and elemental composition were characterized using transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The as-prepared Pd-GQD was subsequently employed as a catalyst for the Heck and decarboxylative cross-coupling reactions and was found to exhibit higher catalytic activity than other reference systems. The expanded substrate scope of various substituted aryl iodides further proved that the GQD is an effective support for preparing new heterogeneous catalysts with improved catalytic performances.

The title compound, C30H44N2O4 [systematic name: 2,6-didecylpyrrolo[3,4-f]isoindole-1,3,5,7(2H,6H)-tetraone], consists of a central pyromellitic diimide moiety with terminal decyl groups at the N-atom positions. The centre of the molecule lies on a crystallographic inversion centre so the asymmetric unit contains one half-molecule. The molecule exhibits a rod-shaped conformation, like other similar compounds of this type, the distance between the ends of terminal decyl groups being 32.45 Å. The packing is dominated by a lamellar arrangement of the molecules, which is reinforced by C—H...O hydrogen bonds and C—O...π interactions, forming a classic herringbone structure. The molecular structure is consistent with the theoretical calculations performed by density functional theory (DFT).

In the present study, the synthesis of CoWO4 (CWO)–Ni nanocomposites was conducted using a wet chemical method. The crystalline phases and morphologies of the Ni nanoparticles, CWO, and CWO–Ni composites were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDAX). The electrochemical properties of CWO and CWO–Ni composite electrode materials were assessed by cyclic voltammetry (CV), and galvanostatic charge–discharge (GCD) tests using KOH as a supporting electrolyte. Among the CWO–Ni composites containing different amounts of Ni1, Ni2, and Ni3, CWO–Ni3 exhibited the highest specific capacitance of 271 F g−1 at 1 A g−1, which was greater than that of bare CWO (128 F g−1). Moreover, the CWO–Ni3 composite electrode material displayed excellent reversible cyclic stability and maintained 86.4% of its initial capacitance after 1500 discharge cycles. The results obtained herein demonstrate that the prepared CWO–Ni3 nanocomposite is a promising electrode candidate for supercapacitor applications.

The title compound, C15H18N2O2S {systematic name: 6-[2-(cyclohexylsulfanyl)ethyl]-5H-pyrrolo[3,4-b]pyridine-5,7(6H)-dione}, was obtained from the reaction of pyridine-2,3-dicarboxylic anhydride (synonym: quinolinic anhydride) with 2-(cyclohexylsulfanyl)ethylamine. The dihedral angle between the mean plane of the cyclohexyl ring and the quinolinic acid imide ring is 25.43 (11)°. In the crystal, each molecule forms two C—H...O hydrogen bonds and one weak C—O...π [O...ring centroid = 3.255 (2) Å] interaction with neighbouring molecules to generate a ladder structure along the b-axis direction. The ladders are linked by weak C—O...π [O...ring centroid = 3.330 (2) Å] interactions, resulting in sheets extending parallel to the ab plane. The molecular structure is broadly consistent with theoretical calculations performed by density functional theory (DFT).

NiMoO4/g-C3N4 was fabricated by a hydrothermal method and used as an electrode material in a supercapacitor. The samples were characterized by XRD, FTIR, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to study the physical and structural properties of the as-prepared NiMoO4/g-C3N4 material. The electrochemical responses of pristine NiMoO4 and the NiMoO4/g-C3N4 nanocomposite material were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). From the CD studies, the NiMoO4/g-C3N4 nanocomposite revealed a higher maximum specific capacitance (510 Fg−1) in comparison to pristine NiMoO4 (203 Fg−1). In addition, the NiMoO4/g-C3N4 composite electrode material exhibited high stability, which maintained up to 91.8% capacity even after 2000 charge-discharge cycles. Finally, NiMoO4/g-C3N4 was found to exhibit an energy density value of 11.3 Whkg−1. These findings clearly suggested that NiMoO4/g-C3N4 could be a suitable electrode material for electrochemical capacitors.

In the title pyridine herbicide {systematic name: 2-[(4-amino-3,5-dichloro-6-fluoropyridin-2-yl)oxy]acetic acid}, C7H5Cl2FN2O3, the mean plane of the carboxylic acid substituent and the pyridyl ring plane subtend a dihedral angle of 77.5 (1)°. In the crystal, pairs of O—H...O hydrogen bonds form inversion dimers with R22(8) ring motifs. These are extended into chains along [011] by N—H...F hydrogen bonds. In addition, intermolecular N—H...O hydrogen bonds and weak π–π interactions [ring centroid separation = 3.4602 (9) Å] connect these chains into a three-dimensional network.

Sonochemical oxidation of organic pollutants in an aqueous environment is considered to be a green process. This mode of degradation of organic pollutants in an aqueous environment is considered to render reputable outcomes in terms of minimal chemical utilization and no need of extreme physical conditions. Indiscriminate discharge of toxic organic pollutants in an aqueous environment by anthropogenic activities has posed major health implications for both human and aquatic lives. Hence, numerous research endeavours are in progress to improve the efficiency of degradation and mineralization of organic contaminants. Being an extensively used advanced oxidation process, ultrasonic irradiation can be utilized for complete mineralization of persistent organic pollutants by coupling/integrating it with homogeneous and heterogeneous photocatalytic processes. In this regard, scientists have reported on sonophotocatalysis as an effective strategy towards the degradation of many toxic environmental pollutants. The combined effect of sonolysis and photocatalysis has been proved to enhance the production of high reactive-free radicals in aqueous medium which aid in the complete mineralization of organic pollutants. In this manuscript, we provide an overview on the ultrasound-based hybrid technologies for the degradation of organic pollutants in an aqueous environment.

Uranyl ion, the most soluble toxic uranium species, is recognized as an important index for monitoring nuclear wastewater quality. The United States Environmental Protection Agency (US EPA) and the World Health Organization (WHO) prescribed 30 ppb as the allowable concentration of uranyl ion in drinking water. This paper reports on a nanohybrid material that can detect uranyl ions spectroscopically and act as a uranyl ion absorbent in an aqueous system. Compound 1, possessing a salicyladazine core and four acetic acid groups, was synthesized and the spectroscopic properties of its UO22+ complex were studied. Compound 1 had a strong blue emission when irradiated with UV light in the absence of UO22+ that was quenched in the presence of UO22+. According to the Job’s plot, Compound 1 formed a 1:2 complex with UO22+. When immobilized onto mesoporous silica, a small dose (0.3 wt %) of this hybrid material could remove 96% of UO22+ from 1 mL of a 100-ppb UO22+ aqueous solution.

Bimetallic nanoparticles (NPs) exhibit advantageous electrical, optical, and catalytic properties. Among the various NP synthesis methods, pulsed laser ablation in liquid (PLAL) is currently attracting much attention because of its simplicity and versatility. In this study, a pulsed laser was used to produce nickel/palladium (Ni/Pd) bimetallic NPs in methanol and deionized water. The morphological and optical properties of the resulting Ni/Pd bimetallic NPs were characterized. The synthesized Ni/Pd bimetallic NPs were used for the dechlorination of 1,2-dichlorobenzene (1,2-DCB) under various conditions. The dechlorination rates of 1,2-DCB while using single (Ni and Pd) and bimetallic (Ni powder/Pd and Ni/Pd) NPs were investigated. The results showed that the Ni/Pd bimetallic NPs with 19.16 wt.% Pd exhibited much enhanced degradation efficiency for 1,2-DCB (100% degradation after 30 min). Accordingly, the results of enhanced the degradation of 1,2-DCB provide plausible mechanism insights into the catalytic reaction.