Selective CO2-to-CO photocatalytic conversion over a TiO2@TPA hybrid synthesized via MOF hydrolysis

Designing efficient and selective photocatalysts for CO 2 conversion under mild and practical conditions remains a significant challenge. This study aims to establish a sustainable strategy for constructing MOF-derived TiO 2 @TPA hybrids that enable efficient charge separation and selective CO 2 -to-CO conversion under low CO 2 concentrations without sacrificial agents. To achieve this, a TiO 2 @TPA hybrid material was synthesized via in-situ hydrothermal transformation of MIL-125(Ti) in water at 100 °C, without the use of organic solvents or high-temperature calcination. The resulting composite integrates TiO 2 nanocrystals with polymeric terephthalic acid (TPA) through Ti–O–C bonds, forming a stable interface that promotes ligand-to-metal charge transfer (LMCT). This interfacial structure enhances visible-light absorption and facilitates efficient charge separation. When applied to photocatalytic CO 2 reduction under low CO 2 concentrations (∼10 %), the TiO 2 @TPA hybrid achieved highly selective CO generation without the need for sacrificial agents or photosensitizers. In situ infrared spectroscopy and surface photovoltage analysis revealed the formation and stabilization of *COOH intermediates, elucidating the enhanced reaction pathway. This study demonstrates a scalable strategy for constructing MOF-derived hybrid photocatalysts and provides insights into interfacial design for selective CO 2 separation and conversion.