An intrinsic kinetic model for liquid‐phase photocatalytic hydrogen production

Abstract

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.

Advanced Surface of Fibrous Activated Carbon Immobilized with FeO/TiO2 for Photocatalytic Evolution of Hydrogen under Visible Light

“…The highest evolution of hydrogen exhibited by FeO‐TiO 2 /ACF, which has a proper amount of delocalized π ‐electronic systems, demonstrates that the number of hydroxyl groups available on the catalyst surface is an important factor because it affects the affinity of substrate molecules. The hydroxyl groups on the catalyst surface dissociate under acidic and basic conditions according to the form of TiOH+H + from TiOH 2 + and form of TiO+H + from TiOH .…”

“…Additionally, the FeO‐TiO 2 immobilized fabric carbon surface improves the absorption of visible actinic rays which is due to the bonding between C–O–Ti with TiO 2 ‐FeO, that is additionally favorable for increased hydrogen production . The hydroxyl groups on the catalyst surface dissociate under acidic and basic conditions according the form of TiOH+H + from TiOH 2 + and TiO+H + from TiOH . Moreover, the carbonaceous ACF surface with immobilized FeO‐TiO 2 material is hydrous with Fe–O–Ti because of the reaction with water molecules or hydroxyl ions, creating additional OH/OOH radicals through transfer of electrons via localized holes , .…”

Towards controlled bubble nucleation in microreactors for enhanced mass transport

“…This latter case would be less likely to occur in conventional APR based on reported kinetic constants, although it would potentially be encountered in photoreforming in microreactors. 55,56 A 2nd order Lagrange polynomial basis was used to calculate the concentration profile and the velocity/pressure was calculated using a P2-P1 discretization basis. Mesh independence was assessed through successive refinement of the mesh and examining when the outlet concentration became constant at three decimal places, as well as examining the solution in the case without a catalytic wall which yielded the expected uniform concentration profile at steady-state.…”

“…The density of the fluid was 834 kg m −3 and the viscosity 1.2 × 10 −4 cP, taken as the values for water at ∼500 K and 30 bar, which are representative conditions for APR. 12,14,15,[55][56][57][58] The bulk concentration in the microchannel was studied by solving the convection-diffusion equation:…”

Photocatalytic toluene degradation: braiding physico-chemical and intrinsic kinetic analyses

“…Although numerically and computationally complex, intrinsic kinetic formalisms have been previously utilized to study photo-catalytic processes. [20][21][22] However, only few works tested the results coming from kinetic studies with parallel physico-chemical studies coming from independent spectroscopic 23,24 or adsorption 25 studies. Here, we wish to go a step forward in order to braid chemical and chemical engineering information into a kinetic procedure that takes into account initial and independently obtained physico-chemical information to test the results of the kinetic formalism and, at the same time, fixing numerical details of such procedures to ensure that the kinetic formalism by itself can provide useful physico-chemical information.…”