Unique advantages of 2D inorganic nanosheets in exploring high-performance electrocatalysts: Synthesis, application, and perspective

Among diverse nanostructured materials, two-dimensional (2D) inorganic nanosheets have attracted intense research interest because of their unique characteristics such as high morphological anisotropy, expanded 2D surface area with many surface active sites, and unique electronic structures. The existence of many surface- and edge-exposed active sites as well as tunable chemical composition with large concentration of redoxable component ions renders 2D inorganic nanosheets as promising electrocatalysts for diverse electrochemical reactions. Additionally, highly anisotropic 2D inorganic nanosheet with high surface-to-volume ratio can be used as efficient hybridization matrix to optimize the electrocatalyst performance of nanostructured material via strong interfacial interaction and synergistic coupling between hybridized species. For the electrocatalyst application, 2D inorganic nanosheets can play crucial roles as main active components, substrates, additives, and hybrid building blocks in hybrid-type electrocatalysts. In this review, unique advantages of 2D inorganic nanosheets in the design and synthesis of electrocatalysts are discussed with in-depth discussion about their critical roles in 2D nanosheet-based electrocatalysts. Depending on target electrocatalysis reactions, diverse examples of 2D inorganic nanosheet-based electrocatalysts are surveyed along with their versatile characterization techniques. Future research perspectives for the exploration of 2D inorganic nanosheet-based electrocatalysts are presented to provide valuable insights for the development of high-performance electrocatalysts applicable for emerging fields of renewable energy technologies.