• Clean Technology
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• v.19 no.1
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• pp.13-21
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• 2013

The hydrogenolysis of cellulose into polyols was examined over Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ catalysts containing different Cs fractions. The surface area and Pt dispersion of Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ catalysts were found to increase with Cs content. Similar polyol yields were obtained over Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ catalysts irrespective of their Cs content. The catalytic activity of Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ was comparable to that of Ni/W/SBA-15 and combined catalytic systems such as Pt/AC+$H_3PW_{12}O_{40}$ and Pt/AC + $Cs_{3.0}PW_{12}O_{40}$. Some polyanion species were found to leach from the Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ catalyst during the course of the reaction.

• Journal of Hydrogen and New Energy
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• v.22 no.1
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• pp.1-12
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• 2011

To improve the mechanical properties, such as durabilities and antioxidative characteristics, the covalently cross-linked (CL-) SPEEK (sulfonated polyether ether ketone)/Cs-substituted HPA (heteropoly acid) organic-inorganic composite membranes (CL-SPEEK/Cs-HPAs), have been intensively investigated. The composite membrane were prepared by blending cesium-substituted HPAs (Cs-HPAs), including tungstophosphoric acid (TPA), molybdophosphoric acid (MoPA), and tungstosilicic acid (TSiA) with cross-linking agent content of 0.01 mL. And composite electrolytes composed of Cs-HPAs, prepared by immersion (imm.) and titration (titr.) methods to increase the stability of HPAs in water, were applied to polymer electrolyte membrane electrolysis (PEME). As a result, the proton conductivity of Cs-substituted composite membranes increased rapidly over $60^{\circ}C$ but mechanical properties, such as tensile strength, decreased in accordance with added Cs content. The bleeding-out of Cs-TPA membranes by titration method (50 vol.% Cs) decreased steadily to 2.15%. In the oxidative stability test by Fenton solution, the durability of membranes with Cs-HPA significantly increased. In case of CL-SPEEK/ Cs-TPA membrane, duration time increased more than 1200 hours. It is expected that even though CL-SPEEK/Cs-MoPA membrane shows the high proton conductivity, electrocatalytic activity and cell voltage of 1.80 V for water electrolysis, the CL-SPEEK/Cs-TPA (imm.) is more suitable as an alternative membrane in real system with the satisfactory proton conductivity, mechanical properties, anti-oxidative stability and cell voltage of 1.89 V.