TPSR of CO hydrogenation on Co/Nb2O5/Al2O3 catalysts

This study involves the characterization of a series Co/x% Nb2O5/Al2O3 catalysts. The temperature-programmed surface reaction technique (TPSR) and in situ diffuse reflectance spectroscopy (DRS) results have shown a transient behavior of the catalysts, distinguishing very well the Co/Al2O3 from the Co/Nb2O5·Al2O3 catalysts. DRS and temperature-programmed reduction (TPR) results indicate the presence of Co2+, besides Co0 and Co0–NbOx, which affect greatly the performance of the catalysts. These results allowed us to propose that the interface Co2+–Co0 is responsible for the mathanation reaction, while the Co0–NbOx is responsible for the hydrocarbon chain grow. The relative amount of each specie on the surface plays a fundamental role on the selectivity behavior of CO hydrogenation.