Mechanism of Ce/La/Zr doping on the structure and anti-coking performance of Ni/MgO-MgAl_(2)O_(4) catalystOA

Dry reforming of methane(DRM),which simultaneously converts CH_(4)and CO_(2)into syngas,represents a promising strategy for greenhouse gas mitigation and carbon‑neutral feedstock production.However,Ni‑based catalysts commonly suffer from severe sintering and carbon deposition under high‑temperature,leading to rapid deactivation.In this work,MgO‑MgAl_(2)O_(4)composite supports are employed to regulate Ni loading.Ce,La and Zr are introduced as promoters to investigate their effects on DRM activity,structural stability,and surface oxygen species.The results show that an optimal Ni loading of 12.5%offers highest CH_(4)and CO_(2)conversions.Although the introduction of promoters slightly suppresses catalytic activity in the low‑temperature region,they substantially modify the local structural order of the support and the metal‑support interfacial environment,thereby improving NiO dispersion and increasing the concentration of surface oxygen vacancies and active oxygen species(O_(β)).These changes enhance CO_(2)adsorption‑activation and effectively suppress carbon deposition.After 20 h of DRM reaction,the Ce‑promoted catalyst exhibits the smallest Ni particle growth(6.23→8.07 nm)and the lowest carbon deposition,demonstrating superior structural stability and anti‑coking capability.This study elucidates how Ce,La and Zr promoters enhance the resistance to sintering and coking through interfacial electronic modulation and improved oxygen storage/release capacity,offering valuable guidelines for the rational design of highly stable Ni‑based DRM catalysts.