Highly Stable Ni-B/Honeycomb-Structural Al2O3 Catalysts for Dry Reforming of Methane.

Abstract

Two-component catalysts have garnered significant attention in the field of catalysis due to their ability to inhibit Ni sintering. In the present work, honeycomb-structured Al2O3-supported Ni and B were prepared to enhance coke tolerance during dry reforming of methane (DRM). Transmission electron microscopy (TEM) revealed that the average particle sizes on Ni/Al2O3 and Ni-0.16B/Al2O3 were 7.6 nm and 4.2 nm, respectively, indicating that B can effectively inhibit Ni sintering. After a 100-hour reaction, the conversion of CH4 and CO2 on Ni/Al2O3 decreased by approximately 5%, whereas on Ni-0.16B/Al2O3, there was no significant decrease in CH4 and CO2 conversion, with values of approximately 81.6% and 87.2%, respectively. In situ DRIFT spectra demonstrated that Ni-0.16B/Al2O3 enhanced the activation of CO2, thus improving the catalyst's stability. A Langmuir-Hinshelwood-Hougen-Watson (LHHW) model was developed for intrinsic kinetics, and the resulting kinetic expressions were well fit to the experimental data, with R2 values exceeding 0.9. The activation energies were also calculated. The outstanding stability of Ni-0.16B/Al2O3 can be attributed to its stable honeycomb structure and B's ability to significantly inhibit Ni sintering, reduce catalyst particle size, and enhance coke tolerance.