Sub-monolayer control of the growth of ZrO2 films over ordered mesoporous silica supports and interface tailoring of Ni-Ga catalysts by atomic layer deposition (ALD)

Abstract

Atomic layer deposition (ALD) is a surface technique that can be used to prepare materials with improved characteristics on the atomic scale. The application of this technique for the design of catalysts has already proven effective in improving catalytic activity, selectivity, and stability, modifying the traditional synthesis techniques to maximize the reactive surface area of the material. In the first part of this project, we propose to study the effect of support prepared through the deposition of ZrO2 by ALD in mesoporous silicas (MCM-41 and SBA-15). The use of ALD allows the creation of metal oxides over morphologies with high surface area, like mesostructured silicas, creating the possibility of synthesizing mesostructured oxides of any metal with a high degree of control over pore size due to the atomic level control of ALD. In the second stage of our work, Ni-Ga metals will then be supported through wet impregnation on the mesostructured ZrO2, and the resulting catalyst will be tested for the CO2 hydrogenation to methanol. The ultimate goal to improve the catalytic performance in methanol production by combining the effect of ZrO2-modified supports with the high areas of the mesoporous silicas, preparing a novel mixed-oxide support not yet explored by any other laboratories. Furthermore, in the second part of this project, the aim is to control the size of Ni-Ga nanoparticles via ALD to create islands of the metals, supporting first Ni-Ga on the mesoporous silica surface and then deposit films of ZrO2 by ALD. All the materials prepared will be characterized at the University of California, Riverside by N2 adsorption-desorption, transmission electron microscopy (MET), X-ray diffraction and X-ray photoelectron spectroscopy (XPS). Catalytic evaluations and other characterization techniques that may prove necessary will be performed on return to Brazil. (AU)