Partial oxidation of methane over high coke-resistant bimetallic Pt-Ni/CeO2 catalyst: Profound influence of Pt addition on stability. (29th November 2022)

• Record Type: Journal Article
• Authors: Khatun, Rubina; Bhandari, Sonu; Poddar, Mukesh Kumar; Samanta, Chanchal; Khan, Tuhin Suvra; Khurana, Deepak; Bal, Rajaram
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 92(2022)
• Page Start: 38895
• Page End: 38909
• Publication Date: 2022-11-29
• Subjects: Partial oxidation -- Bimetallic -- Strong metal-support interaction (SMSI) -- Solid-solution -- Oxygen storage capacity; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.09.092
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: We have developed a bimetallic Pt-Ni/CeO2 catalyst by straightforward citric acid complex combustion method for low-temperature partial oxidation of methane. Furthermore, we also compared the catalytic performance of bimetallic Pt-Ni/CeO2 with monometallic Ni/CeO2 catalysts. The bimetallic 0.5%Pt-2.5%Ni/CeO2 (PNC2.5) catalyst exhibited >99% conversion of methane with a H2 /CO ratio of 2, whereas monometallic 2.5%Ni/CeO2 (NC2.5) catalyst showed ∼92% methane conversion with a H2 /CO ratio of 1.9 at 700 °C. In addition, the PNC2.5 catalyst does not show any deactivation and structural changes during 500 h time-on-stream (TOS), also confirmed by TEM, Raman, and TGA analysis. Conversely, a substantial activity loss (∼61%) was noticed in the NC2.5 catalyst owing to the coking and sintering of Ni species. The excellent performance of the PNC2.5 catalyst can be attributed to the modified electronic-structural properties. The activation of CH4 molecules was studied by DFT calculation over Pt-Ni/CeO2 (111) and Ni/CeO2 (111) model systems, which explain the promotional effect of Pt in the methane C-H bond activation with ∼8 kcal/mol reduction in the activation barrier. Graphical abstract: Image 1 Highlights: Pt-Ni/CeO2 solid solution is synthesized by combustion method for POM reaction. Inclusion of Pt remarkably enhanced metal dispersion and metal-support interaction. ≥99% conversion of CH4 with 100% selectivity of syngas was achieved at 700 °C. Catalyst was stable up to 500 h without any significant graphitic coke deposition. DFT shows the reduction of C-H bond activation energy by 8 kcal/mol after Pt inclusion.