Controlled atmosphere 13C and 1H MAS NMR study of reforming route of methane with carbon dioxide over Rh/SBA-15

Abstract

The mechanism of methane reforming with carbon dioxide over 1.0 wt.% Rh/SBA-15 catalyst has been studied by the 13C and 1H magic-angle spinning (MAS) NMR spectroscopies under controlled atmosphere condition using 13CH 4 + 12CO 2 and 12CH 4 + 13CO 2 as reactants. The effect of temperature in the region of 298–1023 K on the reaction was investigated and the contents of various 13C and 1H species were obtained quantitatively by the NMR technique. When treated at 573 K, the carbon exchange between methane and carbon dioxide can be observed. With the temperature rising to 773 K, the adsorbed CH 3O* species is formed but no reforming reaction occurs. In the high temperature range of 873–1023 K, the reforming reaction was observed with concomitant appearance of the adsorbed CH 2O* species and the intensity of both CH 3O* and CH 2O* increases with increasing temperature, indicating that the decomposition of CH 3O* to CH 2O* occurs and the products of dry reforming are formed from decomposition of the adsorbed CH 2O* species.