Plasmonic nanostructures to enhance catalytic performance of zeolites under visible light

Abstract

Light absorption efficiency of heterogeneous catalysts has restricted their photocatalytic capability for commercially important organic synthesis. Here, we report a way of harvesting visible light efficiently to boost zeolite catalysis by means of plasmonic gold nanoparticles (Au-NPs) supported on zeolites. Zeolites possess strong Brønsted acids and polarized electric fields created by extra-framework cations. The polarized electric fields can be further intensified by the electric near-field enhancement of Au-NPs, which results from the localized surface plasmon resonance (LSPR) upon visible light irradiation. The acetalization reaction was selected as a showcase performed on MZSM-5 and Au/MZSM-5 (M = H+, Na+, Ca2+, or La3+). The density functional theory (DFT) calculations confirmed that the intensified polarized electric fields played a critical role in stretching the C = O bond of the reactants of benzaldehyde to enlarge their molecular polarities, thus allowing reactants to be activated more efficiently by catalytic centers so as to boost the reaction rates. This discovery should evoke intensive research interest on plasmonic metals and diverse zeolites with an aim to take advantage of sunlight for plasmonic devices, molecular electronics, energy storage, and catalysis.

Sustainable conversion of cellulosic biomass to chemicals under visible-light irradiation

“…24,25 We have found that Au-NPs can significantly enhance zeolite photocatalysis with high product selectivity. 26,27 This research aims to develop new catalysts materials and innovative process. The plasmonic structure of Au-HYT was originally explored and firstly used for cellulose conversion under light irradiation.…”

“…This is feasible because light irradiation can intensify the strongly polarised electrostatic fields of zeolite extra-framework ions. 26,27 Table 1 showed the results of cellulose conversion with various catalysts, including Au-HYT, Au-YT, HYT, YT, HY and HT. The conversion of cellulose proceeded effectively on these catalysts even at mild reactive conditions.…”

“…Particularly, the LSPR effect of Au-NPs under visible light irradiation enhanced the polarity electrical field of the extra-framework cations in zeolites. 26,27 The polarity electrical field benefited to acid strength as well as stretched polarized bonds while attacked by proton H + (step I). Similarly, the subsequent conversion from glucose to HMF went through a dehydration process assisted by solid acid catalysts (see SI, Scheme S1).…”

A P25/(NH4)xWO3 hybrid photocatalyst with broad spectrum photocatalytic properties under UV, visible, and near-infrared irradiation

“…As far as light-harvesting is concerned, most of efforts have been focused on extending the photo-responsive region of photocatalysts to match the utmost of solar energy. The landmark cases, such as N-doped TiO 2 photocatalysts20, plasmonic photocatalysts2122, morphology modification2324252627, composite photocatalysts28293031, TiO 2 films32, were developed to make the photocatalysts to be effective under Vis light.…”

Plasma Generation in a Gas Discharge System With Irradiated Porous Zeolite

“…4 shows the change in discharge current and GDLE intensity with pressure at U 0 = 750 V. The current values increase when the electric field increases for a constant pressure. We suggested that electron emission occurred not only from the surface but also from the cross-sectional surface of porous ZC [22]; thus, electron emission is more increased when using ZC ir . A gas discharge is initiated when a high concentration of electrons from a Si in zeolite framework, Si-O-Si bridging, and water vapor in the pores on the zeolite surface is combined with an anomalously high E in the pores.…”