The filling of carbon nanotubes with palladium metal crystallites is described and it is shown that when the carbon nanotube samples are opened using nitric acid, surface acid groups (C02H and OH) are present on both the nanotubes and nanoparticles and these interact strongly with palladium ions: ultrasound pre-treatment of the carbon nanotube samples prior to the oxidation with nitric acid increases the number of these groups.
Communications
--.-ADVANCED MATERIALSFigures 2a and 2b. Moreover, the nuclei statistically may locate anywhere with different depth of channel, and in turn lead to aligned crystals with different lengths, as shown in Figures 2,3b, and 5a).In conclusion, this communication reports a novel method of preparing molecular sieve membranes with wellorganized crystals on a designed substrate. Synthesis conditions such as temperature, dilution degree of solution, chemical composition (especially, template concentration), and reactant source will influence the crystal nucleation rate and transportation of nutrients for the synthesis of zeolite through the nanometer-sized channels of substrate. By controlling these factors, growth of a locally continuous polycrystalline membrane of aligned VAP04-5 and CoA-P04-5 crystals could be achieved, as confirmed by SEM and Fourier transform images of SEM micrographs. For the first time, the unidirectional alignment of VAP04-5 or CoAP04-5 molecular sieve crystals grown in bundles is achieved.
ExperimentalUsing PTFE-lined autoclaves under autogenous pressure at 180°C and without stirring, membranes of VAP04-5 (or CoAP04-5) crystals supported on anodic alumina were synthesized from aluminum triisopropylate, 85 % orthophosphoric acid, vanadyl sulfate pentahydrate (or cobalt sulfate), tripropylamine. and deionized water. The composition of the reaction gel was 0.95-1.0 PzOs:0.95-I.0A120~:0.0S V20s (or 0.10 CoO2):1.55-6.0 Pr3N: 300-600H20. The pH values in all the experiments were adjusted to 6.0-10.2. The anodic alumina substrate was immersed in the reaction mixture. After 36-48 h of reaction, the samples were washed several times with de-ionized water under ultrasonic vibration and dried at 100 "C for 1 h.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.