Ultrafast microfluidic preparation of highly dispersed Ru/TiO2 catalyst for the hydrodeoxygenation of lignin-derived phenolic compounds

An ultrafast preparation method that coupled the photochemical method with the microfluidic technology to synthesize the highly dispersed Ru/TiO2 catalyst within only 1 min was proposed. This method had an enhanced electron excitation and a high electron transfer efficiency during the preparation process due to the small dimension of the microchannel, which enabled to shorten the preparation time greatly. Much higher metal reduction efficiency was obtained than that of the single photochemical method, and a high Ru metal dispersion on the TiO2 surface can be achieved. Moreover, a strong interaction between the metal site and the support was formed, resulting in more spillover hydrogen. This Ru/TiO2 catalyst presented a high activity on the HDO of phenolic compounds. Guaiacol was converted into cyclohexane with 97.6 % selectivity at 260 °C. The raw lignin-oil also can be upgraded efficiently, with the hydrocarbon content increased from 6.7 % to 69.4 %.