Photoelectrochemical reaction of biomass and bio-related compounds with nanoporous TiO 2 film photoanode and O 2-reducing cathode

Abstract

Photoelectrochemical decomposition of many biomass and related compounds with a nanoporous TiO 2 film photoanode and an O 2-reducing cathode was successfully achieved to generate photocurrents. As long as the compound is either liquid or soluble (or solubilized) in water, it was able to be photodecomposed including even polymeric compound to produce electricity. Not only biomass (such as polysaccharides, proteins, cellulose, lignin, etc.) and bio-related materials (methanol, ethanol, glucose, amino acids, ammonia, urea, etc.), but also other electron-donating compounds, even synthetic polymers, could be photodecomposed generating electricity. The compounds underwent almost complete mineralization, i.e., they decomposed almost completely to produce either CO 2 from carbon compounds or dinitrogen (N 2) from nitrogen compounds such as ammonia. It was estimated that about 78% energy of the compound is converted to electrical energy in a maximum case. A photofuel cell (PFC) was proposed and thus proved that can use varieties of biomass and bio-related compounds including other organic compounds as a direct fuel to generate electricity by using photocatalytic oxidation at a nanoporous TiO 2 film photoanode and an O 2-reducing cathode.