Cu 0 -loaded SBA-15@ZnO with improved electrical properties and affinity towards hydrogen

Abstract A core-shell material was prepared using SBA-15 crystallites as cores for the growth of a ZnO shell, followed by Cu 0 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 Cu 0 NPs 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 Cu 0 NP 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, Cu 0 NPs 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.