(35c) Enhancing Photocatalytic Reduction of CO2 by Using Bimetallic Co-Catalyst and Plasmonic Nanoparticles

Novel methods to fabricate nanostructured composites have inspired the design and development of new nanocomposites for advanced applications in catalysis, sensors, and medicine. We will demonstrate a colloidal route to synthesize TiO₂ based nanocomposites for photocatalytic reduction of carbon dioxide and water to synthetic hydrocarbons. Here, plasmonic Ag@SiO₂ core-shell nanoparticles were synthesized to increase the number of electron-hole pair generation. Metal nanoparticles of Ag, Pt and bimetallic Ag-Pt were used as co-catalysts to assist quick transferring of photo-excited charge carriers to the electrolyte. Photocatalytic reduction experiments were carried out in a home-built reactor fitted with two IR transparent windows that allowed direct monitoring of CH₄ and CO gaseous product formation during photoreduction of CO₂. The nanocomposites were characterized using a combination of several techniques such as dynamic light scattering technique, UV-vis absorption spectroscopy, and transmission electron microscopy.  We find a nearly 10-fold increase in catalytic conversion when both plasmonic and co-catalytic nanoparticles were used synergistically. Synthesis, material characterization, and photo-reduction experimental details will be discussed in the presentation.