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-structuralstructured Al₂O₃-supported Ni and B were prepared to enhance coke tolerance during dry reforming of methane (DRM). Transmission electron microscopy (TEM) results 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-fitted fit to the experimental data, with R² values exceeding 0.9. ActivationThe 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.

Keywords: Coke tolerance; Dry reforming of methane; Honeycomb-structural; Intrinsic kinetics; Stability.