Recent trends in MXene/Metal chalcogenides for electro-/photocatalytic hydrogen evolution reactions

Hydrogen due to high energy density and ecologically benign characteristics can become an excellent energy carrier for a sustainable energy economy and to appease the energy demand of humankind. Moreover, cost-effective and long-lasting photocatalysts can make the hydrogen generating process more economical and suitable. Recently, MXene have become one of the most sought-after composite materials for photocatalytic hydrogen generation. However, the photocstalytic performance can be further enhanced by doping with other semiconductor materials. Transition metal chalcogenides (Transition metals = Cu, Co, Ni, Zn, Cd, Mo, W)/MXene composites and mixed transition metal chalcogenide/MXene nanocomposites have been extensively investigated for the photocatalytic hydrogen generation. These materials possess unique two-dimensional layered structure that ameliorates the photocatalytic water splitting performance by increasing the light adsorption even at low photon flux density. The 2D design assists in reducing the distance necessary to transverse charge carriers to the surface. Because the layered structure tends to trap electrons in the ultrathin layers, 2D materials have unusual optoelectronic properties. In-plane covalent bonding assisted the creation of various heterojunctions and heterostructures in these 2D materials. Water splitting and hydrogen production are aided by the high surface area of these 2D materials. Due to its diverse elemental composition, unique 2D structure, good photoelectronic characteristics, large surface area, and many surface terminations. The design and production of many types of materials used as catalysts for the hydrogen evolution process are discussed in this article.