The energetics of p/n photoelectrolysis cells

This review focuses on the use of inorganic oxide semiconductors for the photoassisted generation of hydrogen from water. Representative studies spanning approximately three decades are included in this review. The topics covered include a discussion of the types of water photosplitting approaches, an ideal photoelectrolysis system, an examination of why oxide semiconductors are attractive for this application, a review of both classical and more recent studies on titanium dioxide, tungsten trioxide, and other binary metal oxides, perovskites and other ternary oxides, tantalates and niobates, miscellaneous multinary oxides, semiconductor alloys and mixed semiconductor composites, and twin-photosystem configurations for water splitting.

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“…2c) have been discussed [74]. Stability issues in photoelectrochemical energy conversion systems have been reviewed [9,13,14].…”

Section: An Ideal Photoelectrolysis Systemmentioning

confidence: 99%

“…Table 9 provides a compilation of the semiconductor photocathode and photoanode combinations that have been examined. Combinations involving n-WSe 2 , n-MoSe 2 , n-WS 2 , n-TiO 2 , p-InP, p-GaP and p-Si semiconductor electrodes have been described [74].…”

Section: Semiconductor Alloys and Mixed Semiconductor Compositesmentioning

confidence: 99%

Hydrogen generation at irradiated oxide semiconductor–solution interfaces

2007

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“…23,24 Many years ago, one of the authors also investigated the efficiency and energetics of p-n systems for photoelectrolysis of haloacids. 25 A similar concept, that is essentially a solar chargeable redox flow battery, is shown in Fig. 2.…”

Section: Alternative Photoelectrochemical Storage Systemsmentioning

confidence: 99%

Perspectives on the photoelectrochemical storage of solar energy

Krol

Parkinson

2017

MRS Energy & Sustainability

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Direct photoelectrochemical water splitting offers several advantages over PV-powered electrolysis and may become the technology of choice in the future. However, significant R&D efforts and breakthroughs are needed to accomplish this goal.The sustainable production of hydrogen would be an important first step for both powering fuel cells and for enabling large-scale and technologically mature gas phase processes to reduce CO 2 and nitrogen to get desired products. Specifically, the central challenge is to produce hydrogen from water using sunlight. Photovoltaics and wind-powered electrolysis are likely to be the technology of choice to produce renewable hydrogen for the next few decades. However, the integration of light absorption and catalysis in 'direct' photoelectrolysis routes offers several advantages, such as lower current densities and better heat management, and may become technologically relevant in the second half of this century. This article discusses the research and development efforts and needed breakthroughs to achieve this goal. New chemically stable semiconductors with a band gap between 1.5 and 2.0 eV and long carrier lifetimes are urgently needed to make efficient tandem devices.Scale-up of these research level devices beyond a few cm 2 introduces mass transport limitations that require creative electrochemical engineering solutions. Last but not least, standardized methods for measuring efficiencies and stabilities need to be implemented and should lead to official benchmarking and certification laboratories to guide commercial scale up efforts. Keywords: photochemical; energy storage; energy generation RevIew DISCUSSION POINTS• Water splitting will be a central challenge for any future fossil fuel-free energy infrastructure that relies on liquid or gaseous chemical fuels.• While the main materials challenge for solar-and wind-driven electrolysis is the development of better catalysts, the main challenge for photoelectrochemical water splitting is to find new chemically stable optimal-bandgap semiconducting light absorbers.• Further progress in the development of photo-driven water splitting generators requires significant additional efforts in electrochemical engineering and the development of standardized methods for benchmarking device performance and stability.

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“…Therefore, a p-n tandem cell is the most promising one due to its high theoretical efficiency and low cost. 10,11 Recently, some n-type semiconductors, BiVO 4 , Fe 2 O 3 and Ta 3 N 5 , have been intensively studied as photoanodes. [12][13][14][15] The band gap of BiVO 4 is too wide (2.4 eV), which leads to a low theoretical efficiency (9.1%), even lower than the minimum efficiency (10%) for practical applications.…”

Section: Introductionmentioning

confidence: 99%