Mechanistic Insights for Dry Reforming of Methane on Cu/Ni Bimetallic Catalysts: DFT-Assisted Microkinetic Analysis for Coke Resistance

Catalysts

SunHee Yoon¹  Nimir Elbashir¹  Minhaj Ghouri¹  Anjaneyulu Chatla¹  Murtaza Khan¹  Ahmed Omran¹ 

[1] Chemical Engineering Program, Texas A&M University at Qatar, Doha 23874, Qatar;

关键词: density functional theory (DFT);    dry reforming of methane (DRM);    Ni₂Cu (111);    bimetallic catalyst;    coke resistance;    catalyst deactivation;   

DOI  :  10.3390/catal10091043

来源: DOAJ

【 摘 要 】

Density functional theory (DFT) calculations have been utilized to evaluate the complete reaction mechanism of methane dry reforming (DRM) over Ni₂Cu (111) bimetallic catalyst. The detailed catalytic cycle on Ni₂Cu (111) catalyst demonstrated superior coke resistance compared to pure Ni (111) and Ni₂Fe (111) reported in the literature. Doping Cu in the Ni–Ni network enhanced the competitive CH oxidation by both atomic O and OH species with the latter having only 0.02 eV higher than the 1.06 eV energy barrier required for CH oxidation by atomic O. Among the C/CH oxidation pathways, C* + O* → CO (g) was the most favorable with an energy barrier of 0.72 eV. This was almost half of the energy barrier required for the rate-limiting step of CH decomposition (1.40 eV) and indicated enhanced coke deposition removal. Finally, we investigated the effect of temperature (800~1000 K) on the carbon deposition and elimination mechanism over Ni₂Cu (111) catalyst. Under those realistic DRM conditions, the calculations showed a periodic cycle of simultaneous carbon deposition and elimination resulting in improved catalyst stability.

【 授权许可】

Unknown