Catalyzing Artificial Photosynthesis with TiO₂ Heterostructures and Hybrids: Emerging Trends in a Classical yet Contemporary Photocatalyst

Titanium dioxide (TiO₂) stands out as a versatile transition-metal oxide with applications ranging from energy conversion/storage and environmental remediation to sensors and optoelectronics. While extensively researched for these emerging applications, TiO₂ has also achieved commercial success in various fields including paints, inks, pharmaceuticals, food additives, and advanced medicine. Thanks to the tunability of their structural, morphological, optical, and electronic characteristics, TiO₂ nanomaterials are among the most researched engineering materials. Besides these inherent advantages, the low cost, low toxicity, and biocompatibility of TiO₂ nanomaterials position them as a sustainable choice of functional materials for energy conversion. Although TiO₂ is a classical photocatalyst well-known for its structural stability and high surface activity, TiO₂-based photocatalysis is still an active area of research particularly in the context of catalyzing artificial photosynthesis. This review provides a comprehensive overview of the latest developments and emerging trends in TiO₂ heterostructures and hybrids for artificial photosynthesis. It begins by discussing the common synthesis methods for TiO₂ nanomaterials, including hydrothermal synthesis and sol–gel synthesis. It then delves into TiO₂ nanomaterials and their photocatalytic mechanisms, highlighting the key advancements that have been made in recent years. The strategies to enhance the photocatalytic efficiency of TiO₂, including surface modification, doping modulation, heterojunction construction, and synergy of composite materials, with a specific emphasis on their applications in artificial photosynthesis, are discussed. TiO₂-based heterostructures and hybrids present exciting opportunities for catalyzing solar fuel production, organic degradation, and CO₂ reduction via artificial photosynthesis. This review offers an overview of the latest trends and advancements, while also highlighting the ongoing challenges and prospects for future developments in this classical yet rapidly evolving field. © 2023 Wiley-VCH GmbH.