Growing concerns about fossil fuel’s environmental impact, along with the recent breakthrough of electric vehicles, have turned research focus to energy storage solutions. Despite the fact that batteries were invented about 200 years ago, modern technologies are required to store energy in a larger grid with a high density. The electrode materials used in energy storage devices such as batteries and supercapacitors play a major role in their overall performance. A lot of materials have been explored but due to appealing electrical and electrochemical properties, MXene has received a lot of interest for energy storage devices. Because of their layered structure and high conductivity, MXenes are promising candidates for energy storage applications. Two-dimensional heterostructured materials are more advantageous than individual building blocks for batteries and supercapacitors. In this review work, we looked at different MXene based heterostructures and their electrochemical performance as electrode materials of batteries. A particular application of MXene in Lithium-ion batteries has been studied. Synthesis and characteristics of MXenes are briefly discussed here. Finally, future prospects and challenges are highlighted.

Global energy consumption will double by 2050, increasing our dependence on fossil fuels in the process. Fossil fuel combustion is predicted to generate 500 tons of CO2 by 2060. Researchers have been working for years to reduce CO2 emissions by converting it into value-added products, like chemicals and fuels. CO2 is an inert gas with a low electron affinity and a high bandgap (13.6 eV). The dissociation of the C=O bond requires a large energy input (750 kJ mol−1), which is only possible under pressure and temperature conditions or using highly efficient catalysts. After discovering graphene in 2004, research on catalysts for CO2 conversion has become a hot topic. Nanomaterials with a large surface area to volume ratio act as catalysts more effectively than their bulk counterparts. The extremely thin thickness of 2D nanomaterials also results in extraordinary electrical and optical properties, which facilitate the process of harvesting energy. In addition, a high density of crystal imperfections like dislocations and point defects can easily be incorporated into 2D materials, which can act as active sites for catalytic reactions. Graphene oxides, graphitic carbon nitrides, 2D metal oxides, MXenes, transition metal dichalcogenides, metal complexes, etc., exhibit promising potential for catalytic CO2 reduction. Chemical conjugates of inorganic and organic compounds are the most effective catalysts in the CO2 reduction reaction. They minimize the cost of using noble elements without compromising efficiency. This chapter addresses 2D hybrid nanomaterials used to reduce CO2 to value-added chemicals and fuels, focusing on their synthesis, properties, applications, and challenges.