Preparation of Amine-Modified Cu-Mg-Al LDH Composite Photocatalyst.

Cu-Mg-Al layered double hydroxides (LDHs) with amine modification were prepared by an organic combination of an anionic surfactant-mediated method and an ultrasonic spalling method using -aminoethyl--aminopropyltrimethoxysilane as a grafting agent. The materials were characterized by elemental analysis, XRD, SEM, FTIR, TGA, and XPS. The effects of the Cu content on the surface morphology and the CO adsorption of Cu-Mg-Al LDHs were investigated, and the kinetics of the CO adsorption and the photocatalytic reduction of CO were further analyzed. The results indicated that the amine-modified method and appropriate Cu contents can improve the surface morphology, the increase amine loading and the free-amino functional groups of the materials, which were beneficial to CO capture and adsorption. The CO adsorption capacity of Cu-Mg-Al N was 1.82 mmol·g at 30 °C and a 0.1 MPa pure CO atmosphere. The kinetic model confirmed that CO adsorption was governed by both the physical and chemical adsorption, which could be enhanced with the increase of the Cu content. The chemical adsorption was suppressed, when the Cu content was too high. Cu-Mg-Al N can photocatalytically reduce CO to methanol with Cu as an active site, which can significantly improve the CO adsorption and photocatalytic conversion.