Synthesis of novel MgAl layered double oxide grafted TiO2 cuboids and their photocatalytic activity on CO2 reduction with water vaporElectronic supplementary information (ESI) available. See DOI: 10.1039/c5cy00216h

A series of magnesium/aluminum (MgAl) layered double oxide (LDO) grafted TiO 2 cuboids (MgAl-LDO/TiO 2 ) with various molar ratios of (Mg + Al) to Ti were synthesized by a combination of hydrothermal and coprecipitation methods, in which the growth of MgAl-LDO platelets was controlled. The MgAl-LDO/TiO 2 composite materials were used for photocatalytic CO 2 reduction with water vapor under UV light irradiation in a continuous-flow reactor. CO was found to be the main product from CO 2 . At near room temperature ( e.g. , 50 °C), MgAl-LDO/TiO 2 did not significantly enhance CO 2 reduction compared with pure TiO 2 cuboids. At a moderately elevated reaction temperature ( e.g. , 150 °C), the MgAl-LDO/TiO 2 sample with an optimum 10 wt.% MgAl-LDO loading demonstrated CO 2 reduction activity five times higher than that of bare TiO 2 cuboids. The photo-induced electrons on TiO 2 may migrate to the MgAl-LDO/TiO 2 interfacial sites to promote CO 2 reduction. Findings in this work may lead to a new area of hybrid adsorbent/photocatalyst materials that are capable of sequential CO 2 capture and photocatalytic conversion. Photocatalytic CO 2 reduction with H 2 O by hybrid MgAl-LDO/TiO 2 materials.