A multi-functional layered double hydroxide (LDH)-modified BiVO4 photoanode exhibits a tremendous cathodic shift of the onset potential and more than 2-fold enhancement in the oxidation efficiency and IPCE value.

Pd catalysts supported on TiO 2 with different crystalline phases were prepared with formaldehyde as reducing agent and examined for hydrodeoxygenation (HDO) of guaiacol. Their properties were characterized by N 2 adsorption, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. Compared to the carbon-supported Pd catalysts, TiO 2 -supported Pd catalysts exhibited higher C−O bond scission ability, which may be attributed to the presence of partially reduced titanium species originating from the reduction of Ti 4+ by spillover hydrogen from Pd at 200 °C on the surface of TiO 2 . Guaiacol was hydrogenated on Pd sites to give 2-methoxycyclohexanol, which diffused to partially reduced titanium species and subsequently reacted with hydrogen from Pd to generate cyclohexane. Anatase TiO 2 -supported Pd catalyst gave the highest HDO activity of guaiacol among the Pd catalysts supported on three types of TiO 2 (anatase, rutile, and their mix, P25), suggesting that more partially reduced titanium species are in favor of the HDO reaction because anatase is facile to reduce by H 2 at 200 °C. Higher selectivity of cyclohexane for Pd/TiO 2 reduced at 500 °C than that reduced at 200 °C further confirmed that the enhanced C−O bond scission ability of Pd/TiO 2 is mainly attributed to the partially reduced titanium species on the surface of TiO 2 .

A series of SiO2–TiO2 binary oxides supported high loading Ni catalysts were prepared using the co-precipitation method and tested in guaiacol hydrodeoxygenation (HDO). The catalysts were characterized using N2 adsorption–desorption, XRD, TEM, FT-IR, XPS, H2-TPD, and NH3-TPD. The formation of Si–O–Ti bond in the SiO2–TiO2 binary oxides was verified by XPS, which can increase the total amount of acidic sites and enhance the interaction between metal Ni and TiO2. The oxygen defect sites of TiO2 were formed near the perimeter of the metal–support interface, leading to generation of Niδ−–OV–Ti3+ interface sites, which play the role of active centers to catalyze guaiacol HDO. These positive factors promoted HDO activity over Ni catalysts supported on binary oxides, compared to Ni loaded on single oxide supports. The selectivity of products indicates relatively high temperature and low H2 pressure are beneficial for producing oxygen-free aromatics in HDO of guaiacol.

TiO2-modified Pd/SiO2 catalysts (Ti x Pd/SiO2) have been prepared using wet impregnation and characterized with N2 adsorption, X-ray diffraction, transmission electron microscopy, and temperature-programmed reduction. Their catalytic performance was examined for hydrodeoxygenation (HDO) of guaiacol as a model component of bio-oil. A smaller Pd particle size was obtained by the addition of TiO2, which may contribute to the high conversion of guaiacol on Ti x Pd/SiO2. A strong interaction between TiO2 and Pd occurred when the catalysts were reduced with H2 at 500 °C. TiO x covered on Pd particles can coordinate the oxygen atom in hydrogenation intermediates and activate the C–O bond that could contribute to the significantly enhanced deoxygenation activity. The results suggest that the catalytic HDO proceeds through hydrogenation of the benzene ring of guaiacol on Pd sites to form 2-methoxycyclohexanol, followed by deoxygenation on the sites at a reduced TiO x –Pd interface to generate cyclohexane.

A series of zeolites were screened for the direct conversion of methane to methanol under isothermal low-temperature stepwise conditions; of the screened zeolites, omega zeolite (MAZ) showed superior performance.