Development of cheap metal catalysts for carbon-neutral fuel production and utilization

Abstract

The efficient generation of carbon-neutral fuels and devices to utilize these alternative fuels remain as formidable challenges to a sustainable energy future. The present work will discuss the development of earth-abundant metal catalysts for the generation of H_2 and CO, a valuable feedstock for the water-gas shift reaction, from the abundant resources of H_2O and CO_2. Relevant to both fuel prodn. and utilization, ultra-low Pt electrodes were also examd. in solid acid devices for water splitting and fuel cell applications. Using mol. species as a basis for understanding catalytic pathways, novel cobalt tetrapyridine complexes were synthesized and characterized for photocatalytic water redn. in the presence of a Ru photosensitizer. Hydrogen evolution was accomplished with turnover nos. greater than 2000 at pH 7. In addn., selective carbon dioxide redn. was catalyzed by a family of nickel complexes supported by carbene and amine donors. A five-fold increase in photocatalytic CO prodn. was obsd. above background reactions in acetonitrile with turnover nos. of up to 98,000 in 7 h. For fuel utilization, hydrogen fuel cells composed of a solid acid membrane were fabricated to study ultralow Pt loading electrodes. Platinum nanoparticles deposited on nano-carbon supports were electrosprayed onto carbon current collectors to create high-surface area electrode composites. The increase in surface area enhances the no. of active triple-phase boundaries between the solid acid electrolyte and Pt and reduces the precious metal loading. Thus, electrospray methods offer a novel approach for catalyst deposition and may have valuable applications for water splitting and fuel cells technologies. This body of work will highlight the necessity of understanding both mol. and surface interactions for advancing catalytic materials to meet our future energy needs.

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