A variety of spherical and structured activated charcoal supported Pt/Fe3O4 composites with an average particle size of ~100 nm have been synthesized by a self-assembly method using the difference of reduction potential between Pt （Ⅳ） and Fe （Ⅱ） precursors as driving force. The formed Fe3O4 nanoparticles （NPs） effectively prevent the aggregation of Pt nanocrystallites and promote the dispersion of Pt NPs on the surface of catalyst, which will be favorable for the exposure of Pt active sites for high-efficient adsorption and contact of substrate and hydrogen donor. The electron-enrichment state of Pt NPs donated by Fe304 nanocrystallites is corroborated by XPS measurement, which is responsible for promoting and activating the terminal C=O bond of adsorbed substrate via a vertical configuration. The experimental results show that the activated charcoal supported Pt/Fe3O4 catalyst exhibits 94.8% selectivity towards cinnamyl alcohol by the transfer hydrogenation of einnamaldehyde with Pt loading of 2.46% under the optimum conditions of 120 ℃ for 6 h, and 2-propanol as a hydrogen donor. Additionally, the present study demonstrates that a high-efficient and recyclable catalyst can be rapidly separated from the mixture due to its natural magnetism upon the application of magnetic field.
A facile one-step co-precipitation method was demonstrated to fabricate amorphous sulfurcontaining calcium phosphate （SCP） nanoparticles, in which the sulfur group was in-situ introduced into calcium phosphate. The resulting SCP exhibited a noticeable enhanced performance for Pb（II） removal in comparison with hydroxyapatite （HAP）, being capable of easily reducing 20 ppm of Pb（II） to below the acceptable standard for drinking water within less than 10 min. Remarkably, the saturated removal capacities of Pb（II） on SCP were as high as 1720.57 mg/g calculated by the Langmuir isotherm model, exceeding largely that of the previously reported absorbents. Significantly, SCP displayed highly selective removal ability toward Pb（II） ions in the presence of the competing metal ions （Ni（II）, Co（II）, Zn（II）, and Cd（II））. Further investigations indicated that such ultra-high removal efficiency and preferable affinity of Pb（II） ions on SCP may be reasonably ascribed to the formation of rodlike hydroxypyromorphite crystals on the surface of SCP via dissolution-precipitation and ion exchange reactions, accompanied by the presence of lead sulfide precipitates. High removal efficiency, fast removal kinetics and excellent selectivity toward Pb（II） made the obtained SCP material an ideal candidate for Pb（II） ions decontamination in practical application.
