Hydrogen production using a platinum modified TiO2 photocatalyst and an organic scavenger. Kinetic modeling

Several TiO 2 based semiconductors with different Pt loadings are prepared using incipient impregnation, wet impregnation and the sol-gel method. These photocatalysts are evaluated in the Photo-CREC-Water II Photoreactor for hydrogen production via water dissociation, using an organic renewable scavenger (ethanol). Results obtained show the influence of the photocatalyst preparation in the production of hydrogen and in the observed quantum yields. Furthermore, it is established that the reaction networks leading to hydrogen production, using various photocatalysts, share common features. This analysis is developed by both identifying and quantifying different chemical species and their changes with irradiation time. Key species in this oxidation-reduction network are hydrogen, hydrogen peroxide, ethanol, methane, ethane, acetaldehyde and carbon dioxide. On this basis, it is shown that under an inert gas atmosphere, ethanol consumption is sub-stoichiometric. This points towards simultaneous ethanol consumption and the formation of the ethanol scavenger.

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“…The average photon energy can be calculated by using the spectrum of the lamp and the following equation [10]: …”

Section: Discussionmentioning

confidence: 99%

“…Therefore, as described in Figure 12, the resulting series-parallel network is of the redox type [10]. Included in this process is the formation of hydrogen peroxide.…”

Section: Hydrogen Formation With Ethanol Scavengermentioning

confidence: 99%

Hydrogen Production via Water Dissociation Using Pt–TiO2 Photocatalysts: An Oxidation–Reduction Network

et al. 2017

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“…Indeed, there is sufficient evidence that F‐hyde is easily decomposed. According to Sanwald et al , it is formed by decomposition from E‐ol, as also reported by Escobedo et al .…”

Section: Resultsmentioning

confidence: 99%

“…in which

k_{j}^{''}

is the apparent kinetic constant composed of

k_{j}^{''} = \frac{k_{j} K_{i} W_{irr}}{V_{L}}

, W irr is the irradiated catalyst weight, and V L is the liquid volume, as described by Escobedo et al . In Eqs.…”

Section: Resultsmentioning

confidence: 99%

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A Kinetic Model of Photocatalytic Hydrogen Production Employing a Hole Scavenger

et al. 2019

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Reactions involved in photocatalytic hydrogen production through water splitting combined with a hole scavenger involve several stages that make kinetic analysis quite complicated. In the present work, a kinetic model for the photocatalytic production of hydrogen has been developed based on competitive adsorption, considering the photocatalytic decomposition of an organic molecule coupled to hydrolysis through photocatalytic water splitting. Parameter estimation is performed by using the Levenberg‐Marquardt method. Model validation results give an estimation of the strength of adsorption of acetol and the acetaldehyde.

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An intrinsic kinetic model for liquid‐phase photocatalytic hydrogen production

2019

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A kinetic study was accomplished to describe the photocatalytic production of hydrogen in liquid phase. A reaction mechanism and a kinetic model were proposed to predict the rate of hydrogen production, which is a function of light intensity, catalyst loading, substrate concentration, and time. To assess the capability of the proposed model, glycerol and ethanol were selected as representative hydrogen sources (substrates). The experimental data performed under different operating conditions, based on Box-Behnken experimental design, were used to train the developed kinetic model, optimize the parameters using genetic algorithms and check its accuracy. The analysis confirms the validity of the model under different operating conditions. In addition, the ability of the model to predict the rate of hydrogen production for other substrates, photocatalysts, and operating conditions was confirmed by comparing model predictions with experimental data from literature.

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Hydrogen production using a platinum modified TiO2 photocatalyst and an organic scavenger. Kinetic modeling

Cited by 27 publications

References 21 publications

Hydrogen Production via Water Dissociation Using Pt–TiO2 Photocatalysts: An Oxidation–Reduction Network

Hydrogen Production via Water Dissociation Using Pt–TiO2 Photocatalysts: An Oxidation–Reduction Network

A Kinetic Model of Photocatalytic Hydrogen Production Employing a Hole Scavenger

An intrinsic kinetic model for liquid‐phase photocatalytic hydrogen production

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