Visible light-driven photothermal Au/Ag/TiO2 trihybrid plasmonic nanomaterial for synthetic fuel production

In the present article, a new numerical investigation is conducted to quantify the fluidic flow-photothermal performance of a trihybrid nano-catalyst for biomethane reforming inside a 1 ?m micro-reactor on gold-silver nanoparticles coated on titanium oxide (TiO2). The model generates a two-way coupling between heat, mass, fluid flow and electromagnetic profiles to simulate the plasmonic effect for the plasmonic photocatalyst in a micro-boundary layer adjacent to the catalyst. The effect of light wavelength on operating parameters and system performance was investigated and discussed. This included chemical conversion, the lower heating value of the syngas, mole fractions of species in the gaseous product, and the spatiotemporal velocity profiles. It was found that light absorptance by the nanoparticles is highest when visible light wavelength within 570 nm < ? < 590 nm is used to stimulate the plasmonic nanostructure. Also, the chemical conversion reached 81% at an exposure time of 1 ?s of visible light. At ? = 570 nm, the produced syngas had a lower heating value of 311 kJ/mol and syngas quality of 0.16, which is suitable for ethanol production. Also, a maximum temperature elevation of 998 K was achieved which is above the minimum temperature required for reforming methane (823 K). The spatiotemporal velocity and chemical conversion profiles across the micro-reactor showed that at exposure times > 5 ?s, both profiles become fully developed resulting in the suppression of chemical conversion.