Performance of carbon-modified Pd/SBA-15 catalyst for 2-ethylanthraquinone hydrogenation

Abstract Silica SBA-15 without removal of template P123 was calcined in an inert atmosphere and the carbon-modified SBA-15 thus obtained was used as the support of Pd catalyst for the hydrogenation of 2-ethylanthraquinone (EAQ). The effects of extraction times of P123 in SBA-15 with water prior to inert calcination and calcination temperature on the structure and catalytic performance of Pd catalyst were studied. The results of elemental analysis, X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma, Fourier transform infrared spectroscopy, Raman spectra, water contact angle measurement, N2 adsorption-desorption, transmission electron microscopy and energy dispersive X-ray mapping showed that carbon content of catalysts varied in the range of 3.4 % and 1.1 % with increasing extraction times from 0 to 6 due to the decrease in the residual amount of P123 in uncalcined SBA-15. With rising calcination temperature, the occurrence state of carbon in catalysts was converted from amorphism into graphite. The Pd catalyst supported on SBA-15 extracted for 3 times and calcined at 650 °C had 2.0 % carbon, and exhibited the highest activity (0.37 molH2·gPd−1·min−1) and selectivity (98.9 %). This is due to the presence of appropriate amount of carbon, which provided a relatively high hydrophobicity without significantly reducing the specific surface area and pore size of SBA-15 support. The high hydrophobicity benefits the adsorption of EAQ from the working solution to the surface of catalyst.