EAGER: Bimetallic nano-structures as versatile photocatalysts

点击翻译按钮获取中文摘要

EAGER: Utilizing bimetallic nanostructures as catalysts for efficient solar-driven chemical conversionA majority of chemical conversion processes utilized for the production of commodity chemicals are carried out using exclusively thermal energy, where 50% of the energy consumed in the United States chemical industry is required for feedstocks, while the other 50% provides thermal energy to drive chemical reactions and purification steps. It is apparent that chemical processes operating at lower temperature and higher selectivity must be developed to enhance energy and atomic (feed stock conversion to product) efficiencies. This EAGER award made to Professor Phillip Christopher at University of California Riverside will permit a new class of materials to be explored that have the potential to overcome the inherent limitations of thermal driven processes and allow for solar-assisted chemical conversions at lower temperatures and with higher selectivities. These new catalysts are hybrid materials employing very specific silver species for their interactions with solar energy and other metal species which will improve the selectivity for reactions. This research has potential for significant societal impact through the introduction of new processes that begin to address environmental concerns from burning fossil fuels to drive chemical processes. Christopher plans to include multidisciplinary educational experiences for a diverse audience through hands on research and in class education. Specifically, a relationship with Riverside Community College (RCC) has been developed that will give students from this two-year Hispanic Serving Institution internship opportunities in the Christopher laboratories. This will be a useful experience for RCC students to facilitate their transition from a community college style education to a major research University and to spark their interest in basic research, thus encouraging their enrollment in education beyond the Bachelor?s level.This project will undertake basic research into the synthesis and photocatalytic properties of a new generation of materials that have the potential to increase energy efficiency and chemical selectivity for a wide range of industrial chemical and fuel production processes. The overarching vision of this project is to investigate hybrid materials that exploit unique interactions of Ag with the solar spectrum and the excellent catalytic functionality of more versatile metals (Pt) to selectively drive important chemical reactions using solar energy. Hetero-structured bimetallic nanoparticles consisting of Ag nanoparticle cores and Pt shells or deposited particles will be synthesized using a seed mediated process. Ag nanocubes will be synthesized via the polyol process and Pt will be deposited on pre-synthesized Ag cubes by reduction of Pt salts in an aqueous solution. Crucial synthesis conditions including temperature, precursor injection rate and reductant strength will be varied to control the growth mechanism, and the resulting structures will be characterized using numerous methods. Nanostructures will be tested for their activity in the CO oxidation reactions as a function of temperature, reactant partial pressure, illumination intensity and wavelength. The results will be compared to control catalysts consisting only of Pt and Ag on insulating and semiconducting supports to demonstrate unique properties of the bimetallic Pt/Ag nanostructures. The demonstration of unique photocatalytic reactivity of bimetallic plasmonic nanostructures will open avenues towards the use of solar energy to selectively drive a much wider range of chemical reactions than executable on current classes of semiconductor-based photocatalysts.