Hydrogen Production by Electrolysis and Photoelectrochemical System

Sim, Uk; Jin, Kyoungsuk; Oh, Seungtaeg; Jeong, Dae Hong; Moon, Jung Hwan; Oh, Jihun; Nam, Ki Tae

doi:10.1002/9781118991978.hces223

Cited by 1 publication

(4 citation statements)

References 182 publications

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“…Graphene, an ultrathin, flat monolayer of carbon atoms, continues to attract extensive interest because of its outstanding electronic and structural properties, which make it a promising candidate for touch-screen displays, photonics, and optoelectronics, and energy storage systems. − In our previous reports, a graphene-silicon electrode was found to be effective for the HER because of its superior transmittance, oxidation barrier, and abundant reaction sites for electron transfer. ,, In another study, we treated graphene with nitrogen plasma to increase the number of active sites, including doping sites and defect sites to enhance the HER, and proposed nitrogen-doped graphene quantum sheets (N-GQSs) and silicon nanowires to further improve efficiency through orthogonalization of incidental light absorption and charge carrier collection. The combination of optimized Si nanowires and N-GQSs showed an applied bias photon-to-current efficiency (ABPE) of 2.29%.…”

Section: Introductionmentioning

confidence: 99%

Double-Layer Graphene Outperforming Monolayer as Catalyst on Silicon Photocathode for Hydrogen Production

Sim

Moon

Lee

et al. 2017

ACS Appl. Mater. Interfaces

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Photoelectrochemical cells are used to split hydrogen and oxygen from water molecules to generate chemical fuels to satisfy our ever-increasing energy demands. However, it is a major challenge to design efficient catalysts to use in the photoelectochemical process. Recently, research has focused on carbon-based catalysts, as they are nonprecious and environmentally benign. Interesting advances have also been made in controlling nanostructure interfaces and in introducing new materials as catalysts in the photoelectrochemical cell. However, these catalysts have as yet unresolved issues involving kinetics and light-transmittance. In this work, we introduce high-transmittance graphene onto a planar p-Si photocathode to produce a hydrogen evolution reaction to dramatically enhance photon-to-current efficiency. Interestingly, double-layer graphene/Si exhibits noticeably improved photon-to-current efficiency and modifies the band structure of the graphene/Si photocathode. On the basis of in-depth electrochemical and electrical analyses, the band structure of graphene/Si was shown to result in a much lower work function than Si, accelerating the electron-to-hydrogen production potential. Specifically, plasma-treated double-layer graphene exhibited the best performance and the lowest work function. We electrochemically analyzed the mechanism at work in the graphene-assisted photoelectrode. Atomistic calculations based on the density functional theory were also carried out to more fully understand our experimental observations. We believe that investigation of the underlying mechanism in this high-performance electrode is an important contribution to efforts to develop high-efficiency metal-free carbon-based catalysts for photoelectrochemical cell hydrogen production.

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Section: Introductionmentioning

confidence: 99%

Double-Layer Graphene Outperforming Monolayer as Catalyst on Silicon Photocathode for Hydrogen Production

Sim

Moon

Lee

et al. 2017

ACS Appl. Mater. Interfaces

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“…Additionally, hydrogen can be stored and transported easily. Currently, hydrogen is produced on a large scale by reforming hydrocarbons or through the gasification of fossil fuels, both of which produce a large amount of carbon dioxide (CO 2 ) [6]. The production of hydrogen from water splitting is a feasible approach to obtain an environment-friendly energy source.…”

Section: Introductionmentioning

confidence: 99%

“…HER : 4H + + 4e − ↔ 2H 2 E 0 red = 0.00 V vs. RHE (2) The methods of water splitting systems can be separated to electrochemistry, photoelectrochemisty, and photocatalysis, like shown in Figure 1. For the electrolysis of water which is shown in the left portion of Figure 1, the standard oxidization potential of the OER is defined as 1.23 V corresponding to a relative hydrogen electrode (RHE) and the reduction potential of HER is 0 V (vs. RHE) [6]. However, in the practical water splitting process, a larger applied potential is required because of disadvantageous factors such as activation energy, ion, and gas diffusion as well as factors related to the device.…”

Section: Introductionmentioning

confidence: 99%

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Low Dimensional Carbon-Based Catalysts for Efficient Photocatalytic and Photo/Electrochemical Water Splitting Reactions

et al. 2019

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A universal increase in energy consumption and the dependency on fossil fuels have resulted in increasing severity of global warming, thus necessitating the search of new and environment-friendly energy sources. Hydrogen is as one of the energy sources that can resolve the abovementioned problems. Water splitting promotes ecofriendly hydrogen production without the formation of any greenhouse gas. The most common process for hydrogen production is electrolysis, wherein water molecules are separated into hydrogen and oxygen through electrochemical reactions. Solar-energy-induced chemical reactions, including photocatalysis and photoelectrochemistry, have gained considerable attention because of the simplicity of their procedures and use of solar radiation as the energy source. To improve performance of water splitting reactions, the use of catalysts has been widely investigated. For example, the novel-metal catalysts possessing extremely high catalytic properties for various reactions have been considered. However, due to the rarity and high costs of the novel-metal materials, the catalysts were considered unsuitable for universal use. Although other transition-metal-based materials have also been investigated, carbon-based materials, which are obtained from one of the most common elements on Earth, have potential as low-cost, nontoxic, high-performance catalysts for both photo and electrochemical reactions. Because abundancy, simplicity of synthesis routes, and excellent performance are the important factors for catalysts, easy optimization and many variations are possible in carbon-materials, making them more attractive. In particular, low-dimensional carbon materials, such as graphene and graphitic carbon nitride, exhibit excellent performance because of their unique electrical, mechanical, and catalytic properties. In this mini-review, we will discuss the performance of low-dimensional carbon-based materials for water splitting reactions.

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Hydrogen Production by Electrolysis and Photoelectrochemical System

Cited by 1 publication

References 182 publications

Double-Layer Graphene Outperforming Monolayer as Catalyst on Silicon Photocathode for Hydrogen Production

Double-Layer Graphene Outperforming Monolayer as Catalyst on Silicon Photocathode for Hydrogen Production

Low Dimensional Carbon-Based Catalysts for Efficient Photocatalytic and Photo/Electrochemical Water Splitting Reactions

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