Hydrophobic driving fabrication of highly dispersed PtNi in Zr-doped 3D hollow flower-like MgAl2O4 spheres with abundant O vacancies for enhanced dry reforming of methane

The dry reforming of methane (DRM) could convert CH4 and CO2 into syngas, offering potential for greenhouse gas mitigation. However, DRM catalyst sintering and carbon deposition remain major obstacles. In this study, a highly dispersed PtNi alloy@Zr-doped 3D hollow flower-like MgAl2O4 (AMO) spheres was prepared through a hydrophobic driving strategy. During a 50-hour test at 550 degrees C, the catalyst exhibited no significant decline in CH4 and CO2 conversion rates, demonstrating its excellent anti-sintering and anti-coking performance. The unique anti-coking performance can be attributed to Zr-induced oxygen vacancies, which enhance oxygen mobility and reduce carbon deposition. Besides, doped Zr increases basic active sites, enhancing CO2 adsorption and activation, thus accelerating carbon species conversion. At 700 degrees C, the unique synergy between highly dispersed Pt and Ni enabled CH4 and CO2 conversion rates to reach 67.5 % and 73.8 %, respectively. The incorporation of Pt or Zr extends the Ni-Ni bond and partially coordinates with Ni, enhancing the stability of the Ni lattice. The reaction of CH4 and CO2 follows the Langmuir-Hinshelwood (L-H) mechanism, where both reactant molecules are adsorbed and activated on the metallic sites. Moreover, the effective energy barrier for the CH oxidation pathway is lower by 0.16 eV than that for the C oxidation pathway, which helps suppress the formation of carbon deposits.