Binder-Mediated Regulation of Coating Structure over Monolithic Catalyst and Its Performance in CH4-CO2 Reforming
The CO2 dry reforming of methane (DRM) is pivotal for CO2 utilization within the dual-carbon framework, offering advantages in carbon reduction and value-added chemical production. However, shaped catalysts suitable for industrial-scale DRM remain limited. This work constructs a monolithic catalyst using honeycomb cordierite as the structural support, systematically investigating the effects of organic and inorganic binders on coating structure and catalytic performance. Comparative studies reveal that the active coating fabricated with inorganic aluminum sol exhibits a continuous uniform morphology and excellent adhesion strength. During high-temperature calcination, elemental diffusion within Al2O3 networks bridges the cordierite surface with active catalyst particles, forming a (Ni-Mg)AlxO4 composite structure. This creates robust metal-support interactions between active sites and the residual alumina matrix. The interconnected mesoporous framework provides superior pore confinement, contributing to strong coating adhesion, enhanced activity, and improved resistance to carbon deposition in the monolithic m-NCM-Al-sol catalyst. In contrast, coatings derived from inorganic silica sol suffer from detachment and activity loss due to heterogeneous surface structures and poor adhesion. Organic binders demonstrate inferior performance in macroscopic coating uniformity, adhesion strength, mesoporous confinement, and localized electronic effects, resulting in the poorest catalytic performance. By optimizing aluminum sol coating parameters—binder content, active component dosage, and coating cycles—a synergistic balance between coating thickness and mass transfer is achieved. The optimized catalyst demonstrates excellent DRM performance, providing insights for constructing high-performance shaped catalysts with cordierite coatings.