Advances in MoS₂/TiO₂ heterojunctions for photoelectrochemical hydrogen generation and CO₂ reduction: A comprehensive review

The integration of MoS₂ and TiO₂ into heterojunction structures has gained significant attention for its potential in advancing photoelectrochemical (PEC) systems for hydrogen generation and CO₂ reduction. TiO₂, with its high stability and strong oxidation power, suffers from a wide bandgap that limits its visible-light absorption, whereas MoS₂, a two-dimensional (2D) transition metal dichalcogenide (TMDC), exhibits excellent catalytic properties and a narrow bandgap that enhances light absorption and charge transfer. The MoS₂/TiO₂ heterojunction effectively overcomes these limitations by facilitating charge separation, suppressing recombination losses, and expanding the light absorption range, making it a promising candidate for sustainable energy applications. Notably, MoS₂/TiO₂ heterojunctions have demonstrated versatility in PEC systems, functioning effectively as photoanodes and photocathodes. This review provides a detailed overview of MoS₂/TiO₂-based PEC architectures, including a comparative analysis of their anodic and cathodic roles. Furthermore, recent advances in synthesis strategies, interfacial engineering, charge transfer mechanisms, and performance enhancement techniques have been discussed comprehensively. Additionally, challenges such as interfacial charge recombination, stability issues, and scalable fabrication methods are addressed along with emerging strategies, including defect engineering, plasmonic enhancement, and multi-component heterostructures. By addressing these challenges, MoS₂/TiO₂ heterojunctions hold great promise for the future of solar-driven hydrogen production and carbon capture technologies, contributing to global efforts toward clean energy and environmental sustainability.