Carbothermal synthesis of metal-functionalized nanostructures for energy and environmental applications

Abstract

Carbothermal reduction could be employed as a facile technology for the synthesis of various novel materials, especially transition-metal-functionalized nanostructures. In particular, energy materials, such as ZnO, MnO₂, and LiFePO₄, combined with different carbon nanostructures have been widely synthesized via carbothermal reduction, which could be well established industrially due to its low-cost starting materials. In addition, a variety of carbon sources can be employed as comparatively low-cost carbon precursors for the synthesis of carbonaceous functional materials, such as porous carbon-coated magnetic nanoparticles (e.g., Co₃O₄@C, Fe₃O₄@C, and FeC₃–C). These functional materials have great potential for use in energy and environmental applications. Carbothermal reduction methods possess some incomparable advantages, such as convenience, relatively low cost, and good repeatability, for commercial applications. However, they normally require a relatively high temperature for sustaining carbothermic reaction. Consequently, novel structures can also be derived from renewable, abundant carbon precursors. Examples include lignocellulosic biomass or other biological products derived from food or agricultural wastes (carbohydrates, cellulose, hemicellulose, lignin, chitin, inorganics, and proteins). Thermochemical conversion of biomass, including pyrolysis in an inert environment, has been developed for the production of energy and carbon materials. Furthermore, it is still a potential challenge to simultaneously produce high-quality biofuel products and synthesize value-added functionalized materials via in situ carbothermal reduction. This review will be a powerful resource for stimulating the development of sustainable metal-functionalized nanostructured materials by carbothermal reduction integrated with other advanced technologies, particularly for strengthening efforts towards novel materials for clean energy and environmental applications in the future sustainable society.