Biotemplated heterostructure materials: opportunities for the elaboration of new photocatalysts and selective-oxidation catalysts

Natural biological materials display a large number of sophisticated nanostructures that are difficult to acquire even using the most technologically advanced synthetic methodologies. Since the hierarchical porosity and structure of a catalyst including photocatalysts are becoming increasingly important in the design of catalysts, the potential of biological components of nanoscale dimension for the synthesis of catalysts with novel types of heterostructure and improved activities is being actively explored. This review summarizes the recent advances in the synthesis of nano/microstructures using biotemplates obtained from various types of plants such as Hydrilla, cyanobacteria, reeds (Phragmites communis), leaves, tobacco, and rubber latex. In addition, the applications of synthesized materials in photocatalytic hydrogen production, photocatalytic reduction of Cr(vi), photodegradation of organic pollutants, and catalytic selective oxidation of tetralin, limonene, and cyclohexane have been highlighted. The key issues to improve the catalytic efficiency during the biotemplating procedure are discussed. More importantly, outlooks towards these emerging synthetic approaches have been presented from the perspective of practical application and future challenges are proposed.