Structural design, biomimetic synthesis, and environmental sustainability of graphene-supported g-C3N4/TiO2 hetero-aerogels

Abstract

As an important semiconductor photocatalytic material, titanium oxide (TiO₂) has attracted increasing attention in photocatalytic degradation of organic pollutants due to its high oxidation ability, long-term photostability, and non-toxicity. In this work, we propose a green, facile, efficient, and sustainable strategy to mineralize TiO₂ nanocrystals on biomolecules using biomimetic synthesis. Different from previous reports, we used short peptides with different functional sequences to carry out the biomimetic growth of TiO₂ in the process of peptide self-assembly to obtain peptide nanofiber (PNF)–TiO₂ nanohybrids with controllable structure. In subsequent applications, the biomimetic synthesized PNF-TiO₂ nanohybrids were non-covalently cross-linked with graphene oxide (GO) and graphitic carbon nitride (g-C₃N₄) and freeze-dried to obtain nanohybrids with heterostructured aerogels (hetero-aerogels). The GO/PNF/g-C₃N₄–TiO₂ hetero-aerogel exhibits good photocatalytic activity after thermal annealing and exhibits rapid photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB). Finally, the sustainability of the hetero-aerogels is evaluated using the ranking efficiency product (REP) method. The strategy for preparing TiO₂-functionalized hetero-aerogels via biomimetic synthesis in this study is green, economical, and efficient, and the obtained hetero-aerogels are expected to reveal wide applications in the fields of energy storage, wearable devices, environmental science, and analytical science. More importantly, in future research, we can prepare TiO₂ nanohybrids with different requirements by controlling the structure and morphology of the biological template self-assembly for application in more fields.