Scattering-mediated photothermal heating in plasmonic PES/Au membranes for heterogeneous catalysis

Plasmonic superstructures, which can collect and harness solar energy for conversion into other forms of energy, have attracted significant attention in many chemical systems. Their photocatalytic applications, whereby both the activation energy and reaction temperature can be engineered by solar illumination on the plasmonic nanoparticles, have particularly garnered interest. However, for better optimization of solar-to-chemical conversion, the plasmonic superstructures must possess broadband plasmonic absorption to strongly interact with the incident light. In addition, given that solar radiation has a constant intensity, the loss of incident photons via reflection and transmission should be minimized. To address these issues, we investigated the concept of the scattering-mediated absorption process in polymer-nanoparticle composite membranes. In this approach, porous polymer membranes worked primarily as scatterers to induce the multiple light scattering of incident photons. At the same time, the densely coated plasmonic nanoparticles inside the porous membrane absorbed the scattered light over the broad wavelength region to promote their plasmonic functions extensively. Interestingly, solar radiation on the composite membranes induced local temperature heating inside the membrane, which cannot be achieved by colloidal nanoparticles. Thanks to the local temperature rise, the prepared composite membranes accelerated the kinetics of a model chemical reaction. Because other types of polymer structure can mimic the presented collective properties of polymer-nanoparticle composite membranes, this study could present new opportunities for plasmon-assisted catalytic reactions. Scattering-mediated photothermal process in the PES/Au membranes enabled local temperature heating inside the composite membrane to accelerate the kinetics of a model chemical reaction.