Hydrogen Production via Steam Reforming of Ethanol on Phyllosilicate-Derived Ni/SiO₂: Enhanced Metal–Support Interaction and Catalytic Stability

This paper describes the design of Ni/SiO₂ catalysts obtained from a phyllosilicate precursor that possess high activity and stability for bioethanol steam reforming to sustainably produce hydrogen. Sintering of metal particles and carbon deposition are two major issues of nickel-based catalysts for reforming processes, particularly at high temperatures; strong metal–support interaction could be a possible solution. We have successfully synthesized Ni-containing phyllosilicates by an ammonia evaporation method. Temperature programmed reduction results indicate that the metal–support interaction of Ni/SiO₂ catalyst prepared by ammonia evaporation method (Ni/SiO_2P) is stronger due to the unique layered structure compared to that prepared by conventional impregnation (Ni/SiO_2I). With the phyllosilicate precursor nickel particles highly disperse on the surface, remaining OH groups in the unreduced phyllosilicates promote nickel dispersion and carbon elimination. We also show that high dispersion of Ni and strong metal–support interaction of Ni/SiO_2P significantly promote ethanol conversion and H₂ production in ethanol steam reforming. Ni/SiO_2P produces less carbon deposition compared to Ni/SiO_2I; for the latter, a surface layer of Ni₃C formed during the deactivation

Synthesis of Platinum Nanotubes and Nanorings via Simultaneous Metal Alloying and Etching

Metallic nanotubes represent a class of hollow nanostructures with unique catalytic properties. However, the wet-chemical synthesis of metallic nanotubes remains a substantial challenge, especially for those with dimensions below 50 nm. This communication describes a simultaneous alloying-etching strategy for the synthesis of Pt nanotubes with open ends by selective etching Au core from coaxial Au/Pt nanorods. This approach can be extended for the preparation of Pt nanorings when Saturn-like Au core/Pt shell nanoparticles are used. The diameter and wall thickness of both nanotubes and nanorings can be readily controlled in the range of 14–37 nm and 2–32 nm, respectively. We further demonstrated that the nanotubes with ultrathin side walls showed superior catalytic performance in oxygen reduction reaction