SYNTHESIS OF PtSn NANOPARTICLES ON CARBON NANOTUBES FOR THE SELECTIVE HYDROGENATION OF CITRAL

VIRGINIA RODRÍGUEZ; OSVALDO SCELZA; JULIETA STASSI; PATRÍCIA ZGOLICZ; JULIETA VILELLA; SERGIO DE MIGUEL

Cancun

Congreso; XXV International Materials Research Congress; 2016

Recent advances on carbonaceous materials used as catalytic supports have an important impact in different scientific and technological fields. In this sense, bimetallic nanoparticles supported on carbons are considered to be very promising because of the high possibility of tailoring their electronic and catalytic properties and the possibility of such systems to exhibit interesting yields for future applications. The use of these catalysts for the selective hydrogenation of the carbonyl group of α,β-unsaturated aldehydes into α,β-unsaturated alcohols is an important example in the area of the fine chemical industry.In this work, PtSn catalysts synthesized by two methods, with different Sn/Pt molar ratios and using carbon nanotubes as support, were prepared in order to evaluate the catalytic behavior in the selective hydrogenation of citral to the corresponding unsaturated alcohols (UA) at atmospheric pressure and 70ºC. The methods used to prepare the catalysts were: (i) conventional impregnation followed by reduction of the metallic precursors under H2-flow (CI) and (ii) deposition and reduction of the metallic precursors in liquid phase (RLP). Catalysts were characterized by different techniques: test reactions of the metallic phase, temperature programmed reduction (RTP), X-ray photoelectron spectroscopy (XPS), and transmission electronic microscopy, (TEM ), the catalytic behavior being correlated with the characteristics of the metallic phase. Results showed that the selectivity to UA strongly depends on the preparation method and the capacity to conform proper bimetallic phases. For catalysts prepared by CI, highly ordered PtSn alloys were obtained with low loadings, while highly ordered phases with Sn ionic species distributed in the metallic phase of Pt, were obtained with high loadings of Sn and the formation of PtSn complex. In both cases the bimetallic phases act as Lewis acid sites in order to promote the hydrogenation of the carbonyl group