Pd-Ce-O x /MWCNTs and Pt-Ce-O x /MWCNTs Composite Materials: Morphology, Microstructure, and Catalytic Properties.
Lidiya S KibisAndrey ZadesenetsIlia GarkulArina KorobovaTatyana KardashElena SlavinskayaOlga A StonkusSergey V KorenevOlga Y PodyachevaAndrei I BoroninPublished in: Materials (Basel, Switzerland) (2022)
The composite nanomaterials based on noble metals, reducible oxides, and nanostructured carbon are considered to be perspective catalysts for many useful reactions. In the present work, multi-walled carbon nanotubes (MWCNTs) were used for the preparation of Pd-Ce-O x /MWCNTs and Pt-Ce-O x /MWCNTs catalysts comprising the active components (6 wt%Pd, 6 wt%Pt, 20 wt%CeO 2 ) as highly dispersed nanoparticles, clusters, and single atoms. The application of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) provided analysis of the samples' morphology and structure at the atomic level. For Pd-Ce-O x /MWCNTs samples, the formation of PdO nanoparticles with an average crystallite size of ~8 nm was shown. Pt-Ce-O x /MWCNTs catalysts comprised single Pt 2+ ions and PtO x clusters less than 1 nm. A comparison of the catalytic properties of the samples showed higher activity of Pd-based catalysts in CO and CH 4 oxidation reactions in a low-temperature range (T 50 = 100 °C and T 50 = 295 °C, respectively). However, oxidative pretreatment of the samples resulted in a remarkable enhancement of CO oxidation activity of Pt-Ce-O x /MWCNTs catalyst at T < 20 °C (33% of CO conversion at T = 0 °C), while no changes were detected for the Pd-Ce-O x /MWCNTs sample. The revealed catalytic effect was discussed in terms of the capability of the Pt-Ce-O x /MWCNTs system to form unique PtO x clusters providing high catalytic activity in low-temperature CO oxidation.
Keyphrases
- walled carbon nanotubes
- energy transfer
- high resolution
- highly efficient
- electron microscopy
- computed tomography
- nitric oxide
- magnetic resonance
- quantum dots
- multiple sclerosis
- risk assessment
- crystal structure
- room temperature
- mass spectrometry
- gold nanoparticles
- health risk
- dual energy
- molecularly imprinted
- solid phase extraction