Cu0-loaded SBA-15@ZnO with improved electrical properties and affinity towards hydrogen

Publication date: 15 May 2017
Source:Applied Surface Science, Volume 404
Author(s): N. Bouazizi, S. Louhichi, R. Ouargli, R. Bargougui, J. Vieillard, F. Le Derf, A. Azzouz
A core-shell material was prepared using SBA-15 crystallites as cores for the growth of a ZnO shell, followed by Cu⁰ dispersion. The resulting Cu/SBA-15@ZnO nanostructure displayed higher specific surface area (SSA) and higher number of smaller pores as compared to the starting materials. Dispersion of fine Cu⁰NPs induced a compaction of the host matrice and a marked decay of the hydrophilic character, explained in terms of the involvement of terminal hydroxyl groups in competitive HO:Cu interaction at the expense of H-bridges with water. Heating at 400–450°C seems to trigger ZnO dehydroxylation with possible self-polycondensation and/or the formation of Si-O-Zn bridges. This is an additional explanation of the significant SSA increase and decrease in the average pore diameter. Both ZnO and Cu⁰NP incorporation induced shifts in the UV–vis absorption band towards higher wavelengths, indicating a decrease in the optical band gap energy and an improvement of the conductance properties. As compared to ZnO, Cu⁰NPs produced stronger improvement of the conductance, which was found to increase with higher frequencies. Cu/SBA-15@ZnO also displayed higher affinity towards hydrogen as compared to SBA-15@ZnO and SBA-15 at ambient conditions. These outstanding properties combined to an appreciable thermal stability are worth to be prone to deeper investigations, because they can open promising prospects for Cu/SBA-15@ZnO as sensor, electrode material, electrocatalyst and/or hydrogen capture matrice.

Graphical abstract

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