Pt/graphite catalyst for hydrogen generation by HI decomposition reaction in S-I thermochemical cycle

Abstract

SUMMARYHydrogen is an attractive energy carrier for future because of various reasons. Therefore its large scale production is the need of the hour. One of the ways to achieve this is sulfur iodine thermochemical cycle and HI decomposition reaction is one of the three reactions constituting the cycle. Pt/graphite catalysts with different loading of platinum were prepared by impregnating colloidal graphite with hexachloroplatinic acid solution followed by reduction under N 2 flow. The catalysts prepared have been characterized by X-ray diffraction, Raman, scanning electron microscopy, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller surface area. These catalysts have been employed for liquid phase HI decomposition under different conditions. To evaluate the stability of this catalyst against noble metal leaching under the reaction conditions, the eluent was analyzed by using ICP-OES. Platinum loaded catalysts (0.5%, 1% and 2%) show 8.4%, 17.5% and 23.4% conversion respectively. From the present study we conclude that Pt/graphite is a suitable and stable catalyst for liquid phase HI decomposition reaction.

Pt-Rh/TiO2 /activated carbon as highly active and stable HI decomposition catalyst for hydrogen production in sulfur-iodine (SI) process

“…O'Keefe et al reported that Pt base catalyst showed the high activity to HI decomposition (about 20.2 and 22.5% HI conversion at 673 and 773 K, respectively). Similar results were reported on Pt base catalyst by several groups . Therefore, Pt is active to the HI decomposition reaction; however, HI decomposition activity is still low under a high space velocity (SV) and the stability is insufficient because of the deactivation by I 2 adsorption and reaction.…”

Modeling and experimental assessment of the novel HI‐I 2 ‐H 2 O electrolysis for hydrogen generation in the sulfur‐iodine cycle

“…The influence of operating temperature on the electrolytic performance was analyzed in two opposite aspects. First, increase in temperature enhances the activity of species in the solution and increases the reaction kinetic rate because of the endothermic characteristic of HI decomposition . On contrary, the rising temperature reduces the local current density according to Equation .…”

Numerical study of heat transfer and sulfuric acid decomposition in the process of hydrogen production

“…Another study measured the boiling heat transfer coefficient of the sulfuric acid solution, which is required to design the sulfuric acid decomposer. Tyagi et al evaluated activity and stability of different catalysts for decomposition of hydriodic acid to choose suitable and stable catalyst for engineering application. Zhang et al proposed a detailed kinetic mechanism of homogeneous sulfuric acid solution decomposition and studied the effects of temperature, SO 3 /H 2 O ratio, residence time, and pressure on the decomposition rate of SO 3 to increase the SO 3 conversion.…”