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) series catalyst by H 2 -TPD, NH 3 /H 2 -TPD and thermodynamic calculations. The results have proved that hydrogen spillover on the catalyst surface is related to the hydrogen of H 3 PW 12 O 40 , and finally the equation H + + ( n − 1)H H n + ( n = 2

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Abstract  

A commercial Pd/activated carbon catalyst (10%) was treated using several redox processes: reduction with gaseous hydrogen at 140 °C, reduction by negative electrochemical polarization in acidic and basic environments, oxidation with aqueous hydrogen peroxide, and positive electrochemical polarization in acidic and basic environments. To establish the electrochemical reduction/oxidation conditions, the potentials of hydrogen and oxygen evolution at Pd/AC powder electrodes were determined from cyclic voltammetric (CV) measurements. The samples were examined for the presence of palladium oxide phases on dispersed metal particles using XRD, TPR, and TPD. The metal oxide phase disappeared following hydrogen and electrochemical reduction. Oxidative treatment of the commercial catalyst differentiated the palladium oxide layers on the metal particle surface. Changes in the surface chemistry of the Pd/PdO/AC system were confirmed by the electrochemical behavior of electrodes prepared from the carbon samples.

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saturated N-containing heterocycles among the modified catalysts. The roles of Cr and La were investigated by XRD, XPS, and NH 3 -TPD and the reaction parameters of different aminoalcohols to the corresponding amines were optimized in a continuous fixed

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from the isotherms at P/P 0 = 0.99. The acidity measurement of Al-HMS materials was evaluated by TPD of ammonia in a TPD/TPR 2900 analyzer (Micromeritics). Samples were activated at 500 °C for 1 h in a flow of helium; subsequently, ammonia was

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peak assignment software using Cu K α radiation (λ = 1.54 Å). All the diffraction patterns were recorded in 2θ range of 20–80° by a scanning rate of 2° min −1 . Temperature programmed desorption (TPD) experiments on 0.1 g of catalyst were

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electron microscopy (SEM), X-ray powder diffraction (XRD), temperature program reduction (TPR), and temperature program desorption (TPD) techniques and catalytic measurements have been operated to determine their properties and catalytic performances

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obtained by NH 3 -TPD on a Quantachrome Chembet 3000 chemisorb apparatus. In the first heating before NH 3 -TPD analyses, heating was carried out in He. The samples were first heated at 873 K for 1 h and then cooled to 423 K. Then NH 3 adsorption was

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samples were characterized by XRD, SEM, and NH 3 -TPD with the aim to reveal the relationship between the structure and catalytic efficiency of H-ZSM-5 zeolites. Experimental Chemicals and reagents The

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reaction. These materials were characterized by N 2 adsorption measurements, X-ray diffraction (XRD), MET, temperature-programmed desorption (TPD) of pyridine and 71 Ga MAS-NMR spectroscopy. Experimental Catalysts

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chromatograph with a thermal conductivity detector. Ammonia temperature-programmed desorption (NH 3 -TPD) was conducted on a home-made apparatus. 50 mg of catalyst was loaded in a quartz tubular reactor (i.d. = 6 mm) prior to the measurement, and was

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