Author/Authors :
Vladislav Sadykov، نويسنده , , Vladimir Rogov، نويسنده , , Eugenia Ermakova، نويسنده , , Dmitry Arendarsky، نويسنده , , Natalia Mezentseva، نويسنده , , Galina Alikina، نويسنده , , Natalia Sazonova، نويسنده , , Aleksei Bobin، نويسنده , , Svetlana Pavlova، نويسنده , , Yves Schuurman، نويسنده , , Claude Mirodatos، نويسنده ,
Abstract :
The mechanism of CH4 dry reforming on Pt, Ru, Ni, Ni + Ru-supported perovskite (PrFeOx, LaPrMnCrOx) or fluorite (LnCeZrOx) oxides was studied using a Setaram Sensys DSC TG calorimeter and a pulse kinetic installation. For catalysts in the steady-state, CH4 and CO2 transformation in separate pulses proceeds with the rate and products selectivity equal to that in mixed CO2 + CH4 pulses. Heat effects of separate stages correspond to CH4 oxidation into syngas by strongly bound bridging oxygen forms of support (heat of adsorption up to 650 kJ mol−1 O2 for fluorites and ∼500 kJ mol−1 O2 for perovskites) and their replenishment by CO2 dissociation, respectively. These features demonstrate a step-wise red-ox (Mars-van-Crevelen) mechanism of CH4 dry reforming. Fast oxygen transfer from the sites of oxide support to the metal/oxide interface provides required conjugation of stages.
Keywords :
Bonding strength and reactivity of oxygen species , Pulse microcalorimetry , CH4 dry reforming , Metal clusters , redox mechanism , Perovskite and fluorite oxide supports
