Stabilizing Ni on bimodal mesoporous-macroporous alumina with enhanced coke tolerance in dry reforming of methane to syngas

The bimodal mesoporous-macroporous alumina support was prepared via evaporation-induced self-assembly method (EISA), in which the polystyrene latex spheres with 100 nm diameter size were employed as sacrificial templates to fabricate macropores. The mesoporous-macroporous Al2O3-supported Ni catalyst (Ni/MM-A) was prepared by incipient-wetness impregnation method and applied for dry reforming of methane (DRM) to syngas. Characterizations by XRD, H-2 -TPR, SEM, and TEM revealed that the long-range ordered mesopore structure together with existing macropores was fabricated by using the EISA method, and the Ni particles were mainly stabilized inside the mesoporous channels of Al2O3 support and the strong interaction between Ni and Al2O3 was constructed. The Ni/MM-A catalyst exhibited more excellent catalytic performance in DRM reaction than that over Ni/M-A without macroporous structure. Stability tests for 100 h DRM reaction further indicated that the Ni/MM-A catalyst presented strong catalytic stability, which was significantly attributed to the macroporous structure that allowed the rapid mass transport, enhanced the tolerance to graphitic carbon and reduced the amount of graphitic carbon depositions.