Renewable hydrogen production

Abstract

SUMMARYThe U.S. Department of Energy and the National Renewable Energy Laboratory are developing technologies to produce hydrogen from renewable, sustainable sources. A cost goal of $2.00-$3:00 kg À1 of hydrogen has been identified as the range at which delivered hydrogen becomes cost competitive with gasoline for passenger vehicles. Electrolysis of water is a standard commercial technology for producing hydrogen. Using wind and solar resources to produce the electricity for the process creates a renewable system. Biomass-to-hydrogen processes, including gasification, pyrolysis, and fermentation, are less well-developed technologies. These processes offer the possibility of producing hydrogen from energy crops and from biomass materials such as forest residue and municipal sewage. Solar energy can be used to produce hydrogen from water and biomass by several conversion pathways. Concentrated solar energy can generate high temperatures at which thermochemical reactions can be used to split water. Photoelectrochemical water splitting and photobiology are long-term options for producing hydrogen from water using solar energy. All these technologies are in the development stage.

Local structural models of complex oxygen- and hydroxyl-rich GaP/InP(001) surfaces

“…However, optimizing semiconductor-based photoelectrode materials for hydrogen evolution has proven extremely difficult, in part because the microscopic details of the chemical processes active on the exposed photoelectrode remain poorly understood, as does the connection of these processes to the specific electronic and atomic structures of the semiconductor surface and interface [2][3][4] . This is further complicated by the range of materials properties that must be simultaneously satisfied, including a band gap matched to the visible spectrum; proper band-edge alignment for driving the water redox reaction at the interface; good carrier mobility; stability under operating conditions in an electrolyte solution; and potential for catalyzing the surface water-splitting reaction 1, 3 .…”

Insights from Crystal Size and Band Gap on the Catalytic Activity of Monoclinic BiVO4

“…Solar energy being the most abundant energy source has been widely exploited for thermal and electrical power generation [1], [4]; however, due to a higher convenience of a means of chemical energy storage, such as H 2 , as compared to electricity, solar fuels have been regarded as one of the most promising technological concepts due to its potential higher efficiency and environmental suitability [5]- [7].…”

Hydrogen Generation through Solar Photocatalytic Processes: A Review of the Configuration and the Properties of Effective Metal-Based Semiconductor Nanomaterials

“…However, such efficiencies were recorded under UV light irradiation and have limited significance for solar implementations. The highest quantum yields recorded under visible light irradiation (e.g., <3%) are still far from reaching the benchmark value (>10%) suggested for real applications [97,98]. Besides traditional metal oxide-based photocatalysts, several new complex nanocomposites based on nitrides, oxynitrides, metal sulfides, metal oxysulfides and tantalates have been studied [93].…”