Todd Deutsch

Accelerating materials development for photoelectrochemical hydrogen production: standards for methods, definitions, and reporting protocols

Photoelectrochemical (PEC) water splitting for hydrogen production is a promising technology that uses sunlight and water to produce renewable hydrogen with oxygen as a by-product. In the expanding field of PEC hydrogen production, the use of standardized

Technical and economic feasibility of centralized facilities for solar hydrogen production via photocatalysis and photoelectrochemistry

Photoelectrochemical water splitting is a promising route for the renewable production of hydrogen fuel. This work presents the results of a technical and economic feasibility analysis conducted for four hypothetical, centralized, large-scale hydrogen production plants based on this technology. The four reactor types considered were a single bed particle suspension system, a dual bed particle suspension system, a fixed panel array, and a tracking concentrator array. The current performance of semiconductor absorbers and electrocatalysts were considered to compute reasonable solar-to-hydrogen conversion efficiencies for each of the four systems. The U.S. Department of Energy H2A model was employed to calculate the levelized cost of hydrogen output at the plant gate at 300 psi for a 10 tonne per day production scale. All capital expenditures and operating costs for the reactors and auxiliaries (compressors, control systems, etc.) were considered. The final cost varied from

Cobalt-phosphate (Co-Pi) catalyst modified Mo-doped BiVO4 photoelectrodes for solar water oxidation

1.60–

Enhanced Photoelectrochemical Responses of ZnO Films Through Ga and N Codoping

10.40 per kg H2 with the particle bed systems having lower costs than the panel-based systems. However, safety concerns due to the cogeneration of O2 and H2 in a single bed system and long molecular transport lengths in the dual bed system lead to greater uncertainty in their operation. A sensitivity analysis revealed that improvement in the solar-to-hydrogen efficiency of the panel-based systems could substantially drive down their costs. A key finding is that the production costs are consistent with the Department of Energys targeted threshold cost of

Nanoporous black silicon photocathode for H2 production by photoelectrochemical water splitting

2.00–

Sunlight absorption in water – efficiency and design implications for photoelectrochemical devices

4.00 per kg H2 for dispensed hydrogen, demonstrating that photoelectrochemical water splitting could be a viable route for hydrogen production in the future if material performance targets can be met.

Synthesis of band-gap-reduced p-type ZnO films by Cu incorporation

A cobalt-phosphate based oxygen evolution catalyst (Co-Pi OEC) was electrochemically deposited onto the surface of a porous bismuth vanadate electrode doped with 2 atom% Mo (BiV0.98Mo0.02O4). The porous BiV0.98Mo0.02O4electrode was prepared using a surfactant assisted metal–organic decomposition technique at 500 °C. The comparison of the photocurrent–voltage characteristics of the BiV0.98Mo0.02O4electrodes with and without the presence of Co-Pi catalyst demonstrated that the Co-Pi catalyst enhanced the anodic photocurrent of the BiV0.98Mo0.02O4electrode with its effect more pronounced at lower potentials. A stable photocurrrent density of 1.0 mA cm−2 at 1.0 V vs.Ag/AgCl was achieved under standard AM 1.5 illumination using 0.5M Na2SO4 aqueous solution in phosphate buffer at pH7. Relative to the BiV0.98Mo0.02O4electrode, a sustained enhancement, nearly doubled photocurrent density was observed at 1.0 V vs.Ag/AgCl for Co-Pi/BiV0.98Mo0.02O4 composite photoelectrode. Significant performance gains are obtained on BiV0.98Mo0.02O4electrodes upon modification with Co-Pi water oxidation catalyst.

ZnO nanocoral structures for photoelectrochemical cells

We report on the crystallinity and photoelectrochemical (PEC) response of ZnO thin films codoped by Ga and N. The ZnO:(Ga,N) thin films were deposited by cosputtering at room temperature and followed by postannealing at 500°C in air for 2h. We found that ZnO:(Ga,N) thin films exhibited significantly enhanced crystallinity compared to ZnO doped solely with N at the same growth conditions. Furthermore, ZnO:(Ga,N) thin films exhibited enhanced N incorporation over ZnO doped solely with N at high temperatures. As a result, ZnO:(Ga,N) thin films achieved dramatically improved PEC response, compared to ZnO thin films doped solely with N at any conditions. Our results suggest a general way to improve PEC response for wide-band-gap oxides.

Photoelectrochemical activity of as-grown, α-Fe2O3 nanowire array electrodes for water splitting.

Nanostructured Si eliminates several critical problems with Si photocathodes and dramatically improves a photoelectrochemical (PEC) reaction important to water-splitting. Our nanostructured black Si photocathodes improve the H2 production by providing (1) near-ideal anti-reflection that enables the absorption of most incident light and its conversion to photogenerated electrons and (2) extremely high surface area in direct contact with water that reduces the overpotential needed for the PEC hydrogen half-reaction. Application of these advances would significantly improve the solar H2 conversion efficiency of an ideal tandem PEC system. Finally, the nanostructured Si surface facilitates bubble evolution and therefore reduces the need for surfactants in the electrolyte.

Photoelectrochemical Properties of N-Incorporated ZnO Films Deposited by Reactive RF Magnetron Sputtering

Sunlight absorption in water has a critical impact on solar fuel generation by direct photoelectrolysis because devices are commonly illuminated through the aqueous electrolyte. We show the relevant reference spectra, calculate fundamental solar-to-hydrogen efficiency prospects, and discuss the design implications for unassisted solar water-splitting devices.