Various two-dimensional (2D) materials have demonstrated unique structure-dependent characteristics that are conducive to energy-harvesting applications. Among them, the family of layered MXenes has found a wide range of applications in batteries, supercapacitors, photo- and electrocatalysis, water purification, biosensors, electromagnetic interference shielding, structural composites, etc., owing to their well-defined structure, large surface area, large interlayer distance, and excellent thermal and electrical conductivity. However, layer restacking due to hydrogen bonding or van der Waals forces between the layers considerably impedes the utility of MXenes. To tackle the restacking issues, transition metal dichalcogenides (TMDs) such as MoS₂, WS₂, and MoSe₂ nanosheets have been uniformly dispersed on the surface of MXenes, which not only mitigates the restacking of the MXenes but also improves the electrochemical performance due to the synergistic interaction between MXenes and TMDs. This review describes recent advances in the synthesis of MXene/TMD heterostructures and the nature of the synergistic interactions between TMDs and MXenes in energy-related applications. We further highlight future research directions for MXene/TMD-based materials for energy storage applications.

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.

The present work demonstrates the chemical fixation of CO₂ for the synthesis of organic carbonates using mesoporous hollow marigold CuCo₂O₄ spinel microspheres as a catalyst prepared using the solvothermal method.

Sustainable renewable energy production is being intensely disputed worldwide because fossil fuel resources are declining gradually. One solution is biodiesel production via the transesterification process, which is environmentally feasible due to its low-emission diesel substitute. Significant issues arising with biodiesel production are the cost of the processes, which has stuck its sustainability and the applicability of different resources. In this article, the common biodiesel feedstock such as edible and non-edible vegetable oils, waste oil and animal fats and their advantages and disadvantages were reviewed according to the Web of Science (WOS) database over the timeframe of 1970–2020. The biodiesel feedstock has water or free fatty acid, but it will produce soap by reacting free fatty acids with an alkali catalyst when they present in high portion. This reaction is unfavourable and decreases the biodiesel product yield. This issue can be solved by designing multiple transesterification stages or by employing acidic catalysts to prevent saponification. The second solution is cheaper than the first one and even more applicable because of the abundant source of catalytic materials from a waste product such as rice husk ash, chicken eggshells, fly ash, red mud, steel slag, and coconut shell and lime mud. The overview of the advantages and disadvantages of different homogeneous and heterogeneous catalysts is summarized, and the catalyst promoters and prospects of biodiesel production are also suggested. This research provides beneficial ideas for catalyst synthesis from waste for the transesterification process economically, environmentally and industrially.