Silica-modified Pt/TiO_(2) catalysts with tunable suppression of strong metal-support interaction for cinnamaldehyde hydrogenation

Tuning Strong Metal-support Interactions(SMSI)is a key strategy to obtain highly active catalysts,but conventional methods usually enable TiO_(x) encapsulation of noble metal components to minimize the exposure of noble metals.This study demonstrates a catalyst preparation method to modulate a weak encapsulation of Pt metal nanoparticles(NPs)with the supported TiO_(2),achieving the moderate suppression of SMSI effects.The introduction of silica inhibits this encapsulation,as reflected in the characterization results such as XPS and HRTEM,while the Ti^(4+) to Ti^(3+) conversion due to SMSI can still be found on the support surface.Furthermore,the hydrogenation of cinnamaldehyde(CAL)as a probe reaction revealed that once this encapsulation behavior was suppressed,the adsorption capacity of the catalyst for small molecules like H_(2) and CO was enhanced,which thereby improved the catalytic activity and facilitated the hydrogenation of CAL.Meanwhile,the introduction of SiO_(2) also changed the surface structure of the catalyst,which inhibited the occurrence of the acetal reaction and improved the conversion efficiency of C=O and C=C hydrogenation.Systematic manipulation of SMSI formation and its consequence on the performance in catalytic hydrogenation reactions are discussed.

Boosting Interfacial Polarization Through Heterointerface Engineering in MXene/Graphene Intercalated-Based Microspheres for Electromagnetic Wave Absorption

Multi-layer 2D material assemblies provide a great number of interfaces beneficial for electromagnetic wave absorption.However,avoiding agglomeration and achieving layer-by-layer ordered intercalation remain chal-lenging.Here,3D reduced graphene oxide(rGO)/MXene/TiO_(2)/Fe_(2)C lightweight porous microspheres with periodical intercalated structures and pronounced inter-facial effects were constructed by spray-freeze-drying and microwave irradiation based on the Maxwell–Wagner effect.Such approach reinforced interfacial effects via defects introduction,porous skeleton,multi-layer assembly and multi-compo-nent system,leading to synergistic loss mechanisms.The abundant 2D/2D/0D/0D intercalated heterojunctions in the microspheres provide a high density of polari-zation charges while generating abundant polarization sites,resulting in boosted interfacial polarization,which is verified by CST Microwave Studio simulations.By precisely tuning the 2D nanosheets intercalation in the heterostructures,both the polarization loss and impedance matching improve significantly.At a low filler loading of 5 wt%,the polarization loss rate exceeds 70%,and a minimum reflection loss(RLmin)of-67.4 dB can be achieved.Moreover,radar cross-section simulations further confirm the attenuation ability of the optimized porous microspheres.These results not only provide novel insights into understanding and enhancing interfacial effects,but also constitute an attractive platform for implementing heterointerface engineering based on customized 2D hierarchical architectures.