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MXenes, a class of two-dimensional (2D) materials, have gathered significant attention as excellent electrode materials for various energy applications owing to their remarkable properties such as superior metallic conductivity, abundant surface functionality, high electrical conductivity, hydrophilicity, abundance of surface active sites, enormous cycle life, and ordered lamellar structure. In this study, we present the heterostructured growth of bimetallic Co-NiSe2 on MXene via a simple hydrothermal method. The resulting hybrid structure of Co-NiSe2 exhibits nanorod-like morphology wrapped around MXene sheets. When evaluated as an electrode material for supercapacitors, the Co-NiSe2/MXene composite demonstrates enhanced feasibility, displaying relatively high specific surface area and electrical conductivity, thus exhibiting excellent electrochemical performance. Specifically, the Co-NiSe2/MXene composite exhibits a high specific capacitance of 1394.8 F·g–1 at a current density of 1 A·g–1. Furthermore, the synergetic hybrid material can deliver a high energy density of 20 Wh·kg–1 at a power density of 684 W·kg–1. Importantly, the Co-NiSe2/MXene material exhibits good rate performance and cycle stability, showcasing its potential for advanced energy storage applications. [ABSTRACT FROM AUTHOR]

The anthropogenic carbon dioxide (CO2) fixation and various engineering strategies are gaining very significant attention because of the expansion of the net‐zero carbon environment in the atmosphere. Herein, we designed a sodium aluminate@γ‐alumina (NaAlO2@γ‐Al2O3) catalyst by a simple and facile precipitation and impregnation tactics. A series of different weight percentage NaAlO2@γ‐Al2O3 materials were successfully synthesized and well characterized by using advanced analytical and spectroscopic techniques such as TGA, XRD, FE‐SEM, TEM/HR‐TEM, FT‐IR, Raman, TPD, and XPS analysis. The NaAlO2@γ‐Al2O3 catalyst was employed as a competent catalyst for the CO2 fixation under atmospheric pressure reaction conditions. The catalytic activity results evidently revealed that the cycloaddition reaction successfully achieved 94% styrene oxide conversion and 93% selectivity, along with an 87% yield of the styrene carbonate at 120 °C for 6 h. Furthermore, we comprehensively examined the effect of different reaction parameters such as the effect of sodium aluminate amount, co‐catalyst amount, temperature, and time for CO2 fixation reaction. Additionally, different terminal and internal epoxides were tested under optimized reaction conditions and achieved moderate to excellent yield of the desired cyclic carbonate products. Interestingly, a plausible reaction mechanism was proposed for the styrene carbonate synthesis using NaAlO2@γ‐Al2O3 catalyst surface with the support of characterization and experimental results. Remarkably, the NaAlO2@γ‐Al2O3 catalyst could be easily recoverable and successfully recyclable up to six consecutive cycles without declining its initial catalytic activity along with stable structural and physicochemical properties. [ABSTRACT FROM AUTHOR]

Utilization of anthropogenic CO2 for the synthesis of valuable heterocyclic compounds is a very significant strategy to alleviate environmental issues. Herein, a hollow CeO2 nanosphere (HNS–CeO2) material made using solvothermal-method-assisted synthesis was employed as an efficient catalyst for the selective benzimidazole synthesis under neat and temperate reaction conditions. We examined the controlled reaction conditions for the design of the HNS–CeO2 material through the study of various reaction parameters. Very interestingly, the HNS–CeO2 material exhibited different surface morphological disparities due to the effect of various reaction parameters that were examined comprehensively using field emission scanning electron microscopy analysis. The HNS–CeO2 material was systematically well characterized using various analytical and spectroscopic techniques. The competent catalyst of HNS–CeO2 showed superior catalytic activity (100% conversion, 96% selectivity, and yield) under mild reaction conditions, and these conditions are successfully identified by studying the effect of various reaction parameters. Remarkably, the inherent properties of the HNS–CeO2 catalyst boosted the synergistic effect with the model reagents of o-phenylenediamine, carbon dioxide, dimethylamine borane (DMAB), and base. Moreover, different functional groups substituted benzimidazole compounds are successfully synthesized in good to excellent yields under optimized reaction conditions. The effective contributions of DMAB, base, Lewis acidic, and Lewis basic sites were successfully revealed by proposing a tentative benzimidazole reaction mechanism. Notably, the examined 15 successive recycles with stable catalytic activity performance demonstrated the stable catalytic activity and structural and physicochemical properties of the HNS–CeO2 catalyst. [ABSTRACT FROM AUTHOR]

Since the first discovery of MXenes in 2011, various compositions of MXenes have been developed based on the combinations of different transition metals. Their exceptional and intriguing properties, such as excellent electronic conductivity, hydrophilic nature, and ease of large-scale synthesis, enabled them to be candidates for diverse applications, including energy storage, EMI shielding, biomedical, transparent conductive films, electrocatalysis, etc. However, most efforts have been focused on carbide MXenes and not much on non-carbide (carbonitride and nitride) MXenes. With electronegative nitrogen in non-carbide MXenes, an additional negative charge is induced in the conductive network, enhancing their properties such as wettability, conductivity, and pseudocapacitance. The difficulty in their synthesis has been a significant stopgap in the research progress of non-carbide MXenes. In this review, we have provided a comprehensive overview of the synthesis, properties, and applications of non-carbide MXenes, emphasizing the difference between carbide and non-carbide MXenes for better understanding. The challenges and limitations of non-carbide MXenes and the ways to circumvent them are briefly discussed. The future research directions and the opportunities are also discussed to encourage researchers to investigate non-carbide MXenes further. [ABSTRACT FROM AUTHOR]

In order to meet the current energy storage demands, the rational design of novel nanostructured materials is crucial for the improvement of electrochemical storage and conversion performance. Nanostructured materials have shown promising results in various energy harvesting systems, owing to their multifunctional properties such as a large active surface area, mechanical strength, catalytic ability, excellent ion diffusion, and electronic conductivity. To date, the library of nanostructured materials consists of diverse compositions ranging from oxides, dichalcogenides, carbides to graphene-based and lithium alloys with various morphologies such as zero-dimensional (0D), 1D, 2D and 3D nanomaterials. In particular, nanosponges have exhibited unusual three-dimensional architecture that provides rich surface defects and excellent structural stability resulting in improved catalytic activity. Additionally, the large conducting surface, electronic conductivity and pronounced crystalline phase stability of nanosponges have been utilized to improve the electrode performance drastically. Moreover, the unique sponge-like metallic porous network not only reduces the overall weight of the device but also decreases the consumption of metal usage. In this context, this review particularly highlights the recent progress in the synthesis and properties of noble metals and other metal-based sulphide, oxide, hydroxide and phosphide nanosponges, and their application in electrochemical storage and conversion devices. [ABSTRACT FROM AUTHOR]

Summary: Rational designing of advanced electrocatalysts for oxygen evolution reaction (OER) for energy sustainability is challenging. In this perspective, the fabrication of an efficient ternary hybrid composite electrocatalyst consisting of carbon‐based materials and earth‐abundant metal oxides can be thought as a better choice for large‐scale applications. Hybrid of MoO3 and NiO with carbon material would possibly improve stability and conductivity which can assist in improving OER performance. In this regard, we report the development of MoO3/NiO/activated carbon (MoNiAC) ternary hybrid catalyst by a facile, one‐step solution combustion synthesis (SCS) method. The physiochemical properties of the synthesized catalyst were evaluated by advanced analytical and spectroscopic techniques. The MoNiAC ternary hybrid catalyst exhibited a lower over‐potential (279 mV) (without iR compensation) to attain the current density of 10 mA/cm2, and small Tafel slope of 89 mV/dec was accompanied. The superior activity could be ascribed to the synergism between MoO3, NiO, and AC. Furthermore, the stability graph of the hybrid demonstrated appreciable durability of catalyst for upto 8.33 h. The characterization of after stability catalyst suggested no major disturbance in the morphology as well as element distribution signifying the high durability of the hybrid catalyst in terms of activity as well as morphology. The remarkable features such as appreciable OER activity, promising kinetics, and robustness ameliorated the performance of MoNiAC hybrid as an electrocatalyst for OER. [ABSTRACT FROM AUTHOR]

The involvement of CO2 as a renewable and abundant feedstock toward a carbon balanced future has led to production of several value-added products. The primary focus in the current effort is to assess fixation of CO2 and epoxides into cyclic carbonates by employing state-of-the-art metal complexes as promising catalytic systems. Our attention is restricted to Earth-abundant metals such as aluminum, cobalt, iron, zinc and few transition metals in association with different ligand skeletons used for the structural construction of the respective complexes. This review sequentially categorizes these complexes and provides a panoramic overview of their selective catalytic activities and mechanistic understandings based on experimental and theoretical evidences. [ABSTRACT FROM AUTHOR]

The excess anthropogenic CO 2 depletion via the catalytic approach to produce valuable chemicals is an industrially challenging, demanding, and encouraging strategy for CO 2 fixation. Herein, we demonstrate a selective one-pot strategy for CO 2 fixation into "oxazolidinone" by employing stable porous trimetallic oxide foam (PTOF) as a new catalyst. The PTOF catalyst was synthesized by a solution combustion method using transition metals Cu, Co, and Ni and systematically characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), N 2 sorption, temperature-programmed desorption (TPD), and X-ray photoelectron spectroscopy (XPS) analysis. Due to the distinctive synthesis method and unique combination of metal oxides and their percentage, the PTOF catalyst displayed highly interconnected porous channels along with uniformly distributed active sites on its surface. Well ahead, the PTOF catalyst was screened for the fixation of CO 2 into oxazolidinone. The screened and optimized reaction parameters revealed that the PTOF catalyst showed highly efficient and selective activity with 100% conversion of aniline along with 96% selectivity and yield toward the oxazolidinone product at mild and solvent-free reaction conditions. The superiority of the catalytic performance could be due to the presence of surface active sites and acid-base cooperative synergistic properties of the mixed metal oxides. A doubly synergistic plausible reaction mechanism was proposed for the oxazolidinone synthesis experimentally with the support of DFT calculations along with bond lengths, bond angles, and binding energies. In addition, stepwise intermediate formations with the free energy profile were also proposed. Also, the PTOF catalyst displayed good tolerance toward substituted aromatic amines and terminal epoxides for the fixation of CO 2 into oxazolidinones. Very interestingly, the PTOF catalyst could be significantly reused for up to 15 consecutive cycles with stable activity and retention in physicochemical properties.