Photocatalytic production of H2 is a multi-criteria optimization problem: Case study of RuS2/TiO2

Abstract

Many parameters influence the photocatalytic production of H 2. Identifying and quantifying them is necessary for correct comparison of photocatalysts and right understanding of involved mechanism. In this work, we studied the photocatalytic dehydrogenation of isopropanol with titania-supported ruthenium disulfide. We studied the influence of seven parameters on the photocatalytic activity: the temperature, the composition of the reactive mixture, the mass of the photocatalyst, the flux and the energy of the incident photons, the co-catalyst loading and the nature of the support. Their influence was studied, not only on the rate of hydrogen production (or photon yield) but also on the apparent activation energy and on the preexponential factor, deduced from an Arrhenius law. The photon yield as a function of the co-catalyst loading show an optimum of activity. A 6.9 % photon yield was obtained at 0.84 wt% and = 3.65. The rate-determining step for the photocatalytic dehydrogenation of the isopropanol with RuS 2 /TiO 2 is, at optimal conditions, the electron transfer from TiO 2 to RuS 2. The latter is not favored because of the band diagrams of RuS 2 and TiO 2. The electron transfer can be optimized working with incident photons having a higher energy, thanks to a hot carrier effect observed in RuS 2 /TiO 2 .

Core–Shell β-SiC@PPCN Heterojunction for Promoting Photo-Thermo Catalytic Hydrogen Production

“…It is indicated that in addition to the enhanced hydrogen desorption, the increased temperature mainly contributes to the reduction of the free energy barrier of water dissociation. From the results given in Figure c, it can be known that the β-SiC-50@PPCN allows for thermocatalytic water splitting to produce hydrogen at a suitable elevated temperature, which is consistent with previous study , and the experimental results in Figure S17. Therefore, the core–shell β-SiC-50@PPCN heterojunction not only inhibits photocarrier recombination but also remarkably promotes photo-thermo catalytic hydrogen production by reducing the energy barrier of water dissociation with respect to the increased temperature.…”

RuS2@CN-x with exposed (200) facet as a high-performance photocatalyst for selective C–C bond cleavage of biomass coupling with H–O bond cleavage of water to co-produce chemicals and H2

“…43 For instance, Maheu et al compounded RuS 2 and TiO 2 to obtain RuS 2 /TiO 2 and its photocatalytic activity gradually enhanced with increasing RuS 2 content. 44 The obtained photocatalyst combining RuS 2 and CN has broad application prospects in realizing water splitting and biorefinery. Herein, a hydrothermal-calcination strategy was adopted to anchor RuS 2 nanoparticles onto CN to obtain RuS 2 @CN.…”