title: Advances and recent trends in heterogeneous photo(electro)-catalysis for solar fuels and chemicals.
abstract: In the context of a future renewable energy system based on hydrogen storage as energy-dense liquid alcohols co-synthesized from recycled CO2, this article reviews advances in photocatalysis and photoelectrocatalysis that exploit solar (photonic) primary energy in relevant endergonic processes, viz., H2 generation by water splitting, bio-oxygenate photoreforming, and artificial photosynthesis (CO2 reduction). Attainment of the efficiency (>10%) mandated for viable techno-economics (USD 2.00-4.00 per kg H2) and implementation on a global scale hinges on the development of photo(electro)catalysts and co-catalysts composed of earth-abundant elements offering visible-light-driven charge separation and surface redox chemistry in high quantum yield, while retaining the chemical and photo-stability typical of titanium dioxide, a ubiquitous oxide semiconductor and performance "benchmark". The dye-sensitized TiO2 solar cell and multi-junction Si are key "voltage-biasing" components in hybrid photovoltaic/photoelectrochemical (PV/PEC) devices that currently lead the field in performance. Prospects and limitations of visible-absorbing particulates, e.g., nanotextured crystalline α-Fe2O3, g-C3N4, and TiO2 sensitized by C/N-based dopants, multilayer composites, and plasmonic metals, are also considered. An interesting trend in water splitting is towards hydrogen peroxide as a solar fuel and value-added green reagent. Fundamental and technical hurdles impeding the advance towards pre-commercial solar fuels demonstration units are considered.
authors.affiliation: Heterogeneous Catalysis, Institute of Chemical & Engineering Sciences (ICES, A * Star), 1 Pesek Road, Jurong Island, 627833, Singapore. james_highfield@ices.a-star.edu.sg.
authors.forename: James
authors.initials: J
authors.lastname: Highfield
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry; D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D055668:Photochemical Processes; D010788:Photosynthesis; D059205:Renewable Energy; D012993:Solar Energy; D014025:Titanium / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D002245:Carbon Dioxide; C009495:titanium dioxide; D006859:Hydrogen; D006861:Hydrogen Peroxide; D014025:Titanium; D010100:Oxygen