Novel photocatalysts based on Cd1−Zn S/Zn(OH)2 for the hydrogen evolution from water solutions of ethanol

Kozlova, Ekaterina A.; Markovskaya, Dina V.; Cherepanova, Svetlana V.; Saraev, Аndrey А.; Gerasimov, Evgeny Yu.; Перевалов, Т. В.; Каичев, В. В.; Parmon, Valentin N.

doi:10.1016/j.ijhydene.2014.08.145

Cited by 35 publications

(14 citation statements)

References 47 publications

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“…Besides, the segregated phase g-Zn(OH) 2 highly dispersed on the surface in this sample can also favor a better photoactivity for sample SZ8. It is worth to mention that in other works [16,17] the beneficial effects of segregated phases, such as ZnO and Zn(OH) 2 , in the photoactivity were related.…”

Section: Resultsmentioning

confidence: 82%

Sonochemical synthesis of Cd1−xZnxS solid solutions for application in photocatalytic reforming of glycerol to produce hydrogen

Lopes

Mascarenhas

Silva

2015

Journal of Alloys and Compounds

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Section: Resultsmentioning

confidence: 82%

Sonochemical synthesis of Cd1−xZnxS solid solutions for application in photocatalytic reforming of glycerol to produce hydrogen

Lopes

Mascarenhas

Silva

2015

Journal of Alloys and Compounds

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“…Ainda assim, recentes trabalhos sugerem que o ajuste principalmente de pH e salinidade do meio podem aumentar a estabilidade de CdS por reduzir a solubilidade do sulfeto em solução aquosa, ou mesmo que esta estabilidade pode ser melhorada com a utilização de sulfetos metálicos em sistemas fotocatalíticos multifases, como por exemplo, Cd 1-x Zn x S/Zn(OH) 2 . [48][49][50][51] Apesar do WO 3 funcionar como um fotocatalisador estável para a evolução de O 2 sob luz visível, na presença de um aceitador de elétrons apropriado, a banda de condução do material é mais alta do que o potencial de redução de água e, como resultado, não ocorre a redução do H + a H 2 . A Figura 5 mostra uma ilustração esquemática das estruturas de banda de alguns fotocatalisadores, destacando o dilema acima referido.…”

Section: Combinação: Doadores De Elétrons E Fotocatalisadorunclassified

Estratégias e materiais utilizados em fotocatálise heterogênea para a geração de hidrogênio através da fotólise da água

Marques¹,

Stumbo²,

Canela³

2017

Quim. Nova

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STRATEGIES AND MATERIALS USED IN HETEROGENEOUS PHOTOCATALYSIS APPLIED TO HYDROGEN GENERATION THROUGH WATER PHOTOLYSIS.Among the various technologies for the production of hydrogen fuel, heterogeneous photocatalysis is one of the most promising, especially with the use of semiconductors, notably TiO 2 . However, the use of TiO 2 is limited by hindrances for the photolysis of water, such as wide bandgap, a less negative conduction band reduction potential as compared to that of hydrogen evolution and the high electron/hole recombination rate. Deactivation of the semiconductor can be avoided by the addition of electron-rich compounds (sacrificial reagents) which react irreversibly with the hole, leading to a higher quantum efficiency. Another strategy is the Z scheme. In this system, two different photocatalysts (or photosystems) are combined using a suitable redox mediator. Furthermore, the bandgap can be adjusted by doping with transition metal oxides, with control of metal oxide valence band using p-orbitals of an anion, or s-orbitals of p-block metal ions, or by spectral sensitization. In view of these questions, the purpose of this review article is to describe and discuss recent studies that use a variety of materials for the photocatalytic generation of hydrogen.Keywords: hydrogen; photocatalysis; water splitting; Z scheme. INTRODUÇÃOA procura por fontes que assegurem o suprimento de energia, os altos preços do petróleo e as emissões crescentes de gases do efeito estufa constituem desafios ainda não resolvidos para a economia global e o clima do planeta. Há um consenso na comunidade internacional de que é preciso uma ação urgente para enfrentar os problemas de curto prazo sobre suprimento de energia e mitigar as mudanças futuras do clima, e que a tecnologia e a política são partes desta solução. Dentre as fontes alternativas de energia, o hidrogênio é uma opção atrativa, pois possui elevada energia por unidade de massa (1 kg de hidrogênio contém aproximadamente a energia de 2,7 kg de gasolina), o que facilita a portabilidade da energia. 4 Além disso, sua combustão não gera contaminante, mas apenas água. Embora a combustão do hidrogênio não produza gases de efeito estufa, cerca de 95% do hidrogênio consumido no mundo é gerado a partir de materiais fósseis, sendo obtido principalmente a partir da reforma a vapor de hidrocarbonetos como o metano e nafta (subprodutos do refino do petróleo).5 Este processo, além de demandar grande quantidade de energia para ocorrer (a decomposição do combustível em hidrogênio somente ocorre em temperaturas superiores a 700 o C), produz uma mistura de monóxido de carbono e hidrogênio. Para que a produção de hidrogênio seja considerada sustentável, é necessário o desenvolvimento de processos que atendam aos seguintes requisitos: que a fonte geradora seja renovável; que não haja grande demanda de energia; que não ocorra a produção de poluentes como subprodutos; e que seja um processo técnica e economicamente viável.Os avanços tecnológicos nas áreas de produção de hidrogênio de forma...

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“…Incorporating one or more elements into a parent semiconductor results in the formation of a homogenous solid solution, for example, mixing ZnS and CdS results in Cd 1− x Zn x S. The band gap of the solid solution can be adjusted by tuning the Zn/Cd concentration ratio. Thus, coupling the solid solution with other materials, for example, Pt/Cd 1− x Zn x S/ZnO/Zn(OH) 2 Cd 0.5 Zn 0.5 S/g‐C 3 N 4 , and CdS/Ba 1− x Zn x TiO 3 , offers a flexible technique for band‐gap engineering. The activity of 1 %Pt/Cd 0.2 Zn 0.8 S/ZnO/Zn(OH) 2 exceeds that of 1 %Pt/Cd 0.1 Zn 0.9 S by a factor of 2 .…”

Section: Principle Materials and Performance Of Two‐photon Structuresmentioning

confidence: 99%

“…The activity of 1 %Pt/Cd 0.2 Zn 0.8 S/ZnO/Zn(OH) 2 exceeds that of 1 %Pt/Cd 0.1 Zn 0.9 S by a factor of 2 . The highest H 2 production of approximately 2256 μmol g −1 h −1 is achieved by Pt/Cd 1− x Zn x S/Zn(OH) 2 owing to the fact that its electron reduction potential for zinc hydroxide is higher than that of ZnO . For the CdSe@ZnTe core–shell structure, one of the carriers is confined in the ZnTe core, and it is not accessible for surface reactions.…”

Section: Principle Materials and Performance Of Two‐photon Structuresmentioning

confidence: 99%

Charge Transport in Two‐Photon Semiconducting Structures for Solar Fuels

Haussener

2016

ChemSusChem

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Semiconducting heterostructures are emerging as promising light absorbers and offer effective electron–hole separation to drive solar chemistry. This technology relies on semiconductor composites or photoelectrodes that work in the presence of a redox mediator and that create cascade junctions to promote surface catalytic reactions. Rational tuning of their structures and compositions is crucial to fully exploit their functionality. In this review, we describe the possibilities of applying the two‐photon concept to the field of solar fuels. A wide range of strategies including the indirect combination of two semiconductors by a redox couple, direct coupling of two semiconductors, multicomponent structures with a conductive mediator, related photoelectrodes, as well as two‐photon cells are discussed for light energy harvesting and charge transport. Examples of charge extraction models from the literature are summarized to understand the mechanism of interfacial carrier dynamics and to rationalize experimental observations. We focus on a working principle of the constituent components and linking the photosynthetic activity with the proposed models. This work gives a new perspective on artificial photosynthesis by taking simultaneous advantages of photon absorption and charge transfer, outlining an encouraging roadmap towards solar fuels.

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Novel photocatalysts based on Cd1−Zn S/Zn(OH)2 for the hydrogen evolution from water solutions of ethanol

Cited by 35 publications

References 47 publications

Sonochemical synthesis of Cd1−xZnxS solid solutions for application in photocatalytic reforming of glycerol to produce hydrogen

Sonochemical synthesis of Cd1−xZnxS solid solutions for application in photocatalytic reforming of glycerol to produce hydrogen

Estratégias e materiais utilizados em fotocatálise heterogênea para a geração de hidrogênio através da fotólise da água

Charge Transport in Two‐Photon Semiconducting Structures for Solar Fuels

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