Electrode and Catalytic Materials for Solar Light Harvesting and Fuel Generation Systems

Increasing concerns over climate change require us to develop new sources of energy in an environmentally responsible fashion. Prototypical fuel generation devices driven by solar, electrochemical processes, catalysis, or combinations thereof have been developed. However, further optimization is required in terms of cost, scalability, long term stability, and performance for continued expansion of these methodologies into existing and emerging energy infrastructure. The proposed research program involves the rational design of electrode materials and electrocatalysts for solar light absorption and CO2 and N2 reduction reactions. These goals will be pursued under three themes:Theme 1: Cu and Fe based nanowire arrays as photoelectrodes. The quest for solar absorber materials with exceptional optoelectronic properties that are inexpensive, stable, and non-toxic has been less than successful. Nanowire arrays are a viable alternative to traditional single-crystal or thin film solar light absorbers, as the wire geometry allows for less material usage, enhanced light trapping, efficient carrier collection, and enables mechanical flexibility. Earth abundant and inexpensive metal chalcogenide nanowire arrays made of Cu and Fe oxides and sulfides and their surface chemistry will be developed for light absorption in solar energy conversion devices.Theme 2: Catalyst development and integration with photoelectrodes for CO2 reduction reactions. Mitigating the effects of increasing CO2 concentration by converting it to value added materials is an attractive and promising solution. However, catalysts with high activity, stability, and selectivity need to be developed for efficient and cost effective conversion of CO2 into value added materials. Nanoparticle electrocatalysts composed of Ni, Fe, Co, and Ga alloys will be synthesized and applied towards CO2 reduction. They will be further integrated into nanowire arrays to fabricate optimally performing solar driven CO2 conversion devices. Theme 3. Metal nitrides as electrode materials for N2 reduction. Metal nitrides are robust materials that exhibit exceptional mechanical and chemical stability, and could replace noble metals of high cost and limited supply in catalytic reactions. High surface area metal nitrides will be developed and applied towards electrochemical N2 reduction reactions to synthesize ammonia. In-situ Raman spectroscopy studies will be done to gain fundamental understanding of N2 reactivity on metal nitride surfaces. The proposed research is of importance to Canada as it will allow for the design of materials of increased performance that are free of precious metals and are non-toxic. The proposed research program will train highly qualified personnel with skill sets in material synthesis, characterization, and the applications of materials in energy, sustainable chemistry, and catalytic processes.