Catalytic studies of Pt1 supported on Co/CeO2 nanorods for H2 production in dry reforming of methane

Abstract

A experimental-theoretical catalytic study is presented on 15Co/CeO2-NR catalysts with different Pt contents (0.1, 0.3 and 0.5 wt. %) in the dry reforming of methane (DRM) to obtaining SYNGAS. The synthesis of CeO2 nanorods was carried out by the hydrothermal method, the active phase was added by successive impregnation method starting with Co and then Pt. The catalysts characterization was carried out by DRX, TPR, TPO, TPD-(CO2 and NH3) HRTEM-EDX, including “In-situ heating” in TEM. Furthermore, theoretical studies were performed using DFT for a proposed reaction mechanism and energy transition states for DRM. TEM-EDS showed isolated Pt1 atoms anchored to the surfaces of Co and CeO2 nanorods. The stability of the catalysts in the DRM reaction improved with increasing Pt loading in the samples, while an increase in carbon deposits was observed. Likewise, a pronounced deactivation was observed in the monometallic Co/CeO2-NR sample, along with a lower carbon content, but a greater degree of sintering of the active phase after catalytic reaction, compared to the Pt-base catalysts. According to the results obtained from the transition state analysis using the Halgren-Lipscomb algorithm, it was determined that increasing the number of Pt atoms does not significantly decrease the activation energy. However, experimental tests with the DRM reaction show an increase in the conversion of the reactants when the Pt content in the catalysts is increased, suggesting that the presence of Pt influences catalytic activity through mechanisms other than simply reducing the energy barrier.