Nanoarchitectonics of Non-Noble-Metal-Based Heterogeneous Catalysts for Transfer Hydrogenation Reactions: Detailed Insights on Different Hydrogen Sources

Catalytic transfer hydrogenation (CTH) methodology has drawn profound attention of researchers as an economical and environmentally benign alternate to conventional hydrogenation method. Unlike conventional method, CTH exhibits better reaction efficiency and atom economy, and it makes use of simple, easily accessible, low-cost hydrogen sources. Current research on CTH reactions is oriented toward the development of non-noble-metal-based catalysts due to their high abundance and potential large-scale applicability. In this Review, different organic transformation reactions, such as hydrogenation of nitroarenes, nitriles, alkenes, alkynes, and carbonyl compounds, hydrogenolysis, reductive amination, and reductive formylation reaction using different hydrogen sources have been summarized comprehensively. In addition, synthesis strategies of the non-noble-metal-based heterogeneous catalysts and the structure–activity relationship involving metal–support interaction, single-atom catalysis, and synergistic effect are highlighted. Furthermore, the optimization of the reaction parameters─such as temperature, time, solvents, and additives─for enhancing the catalytic activity and selectivity of the product are discussed in detail. This Review provides detailed insights into the recent progress made in CTH reactions using non-noble-metal-based heterogeneous catalysts with a specific focus on catalyst development, hydrogen sources, and mechanistic exploration.