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Fabrication of 3-D confined spaces with Au NPs: Superior dispersion and catalytic activity

Subhan, Fazle, Aslam, Sobia, Yan, Zifeng, Ahmad, Ayaz, Etim, U.J.
Journal of colloid and interface science 2019 v.540 pp. 371-381
adsorption, catalytic activity, methylene blue, microsatellite repeats, nanogold, p-nitrophenol, porous media, silica, solvents
Gold nanoparticles (Au NPs) as an active noble-metal site have received great attention because of its superior catalytic activity in diverse reactions. However, the activity of Au NPs is strongly dependent on its size and dispersion degree. Therefore, we developed an efficient solid-state reduction (SSR) strategy for the first time to promote the dispersion degree and size of Au NPs in template-occluded KIT-6 (AK) as a support by taking advantage of (i) 3-dimentonal cubic mesoporous structure of support (ii) confined spaces present between template (Pluronic (P) 123) and silica wall of AK where Au NPs locate (iii) interaction of both P123 as template and silica walls of AK with Au NPs highly efficient for Au NPs dispersion and (iv) SSR strategy which avoids competitive adsorption of solvent in the conventional fabrication process. The results revealed that Au-based AK (AuAK) has much better dispersion of Au NPs with smaller sizes than template-free KIT-6 (CK). Moreover, the catalytic activity of AuAK in reduction reactions of p-nitrophenol (P-NP) to p-aminophenol (P-AP) and Methylene blue (MB) to Leuco MB (LMB) is superior than AuCK as well as to those Au-catalysts synthesized via conventional strategies previously. The catalytic performance is also related well with characterization results.