A facile hydrothermal route employing H2O2 as structure-directing agent was explored to fabricate anatase microflowers with dominant {101} facets and anatase microspheres with exposed {001} facets. The influence of H2O2 concentration on crystal structure, morphology, and facet composition of TiO2 was investigated in detail. H2O2 plays a crucial role in determining the crystal structure, morphology, and exposed facets of TiO2. The presence of H2O2 favors the formation of anatase phase. When the concentration of H2O2 was in the range 0.7–3.3 M, anatase microflowers with dominant {101} facets were produced. In contrast, when the concentration of H2O2 was higher than 6.6 M, anatase microspheres with exposed {001} facets were formed. A mechanism was proposed to account for the influence of H2O2 on crystal structure and morphology of TiO2. Photocatalytic degradations of rhodamine B and 2,4-dichlorophenol indicated that anatase microspheres with exposed {001} facets showed much higher photocatalytic activity than anatase microflowers with dominant {101} facets.

A tetrathiotungstate-intercalated NiAl layered double hydroxide (LDH) was synthesized and then calcined under N 2 at various temperatures to prepare a series of NiW presulfurized hydrotreating catalysts. Upon calcination, WS 4 2– in the interlayer decomposes into WS 3 and then WS 2 , releasing sulfur to sulfurize nickel in the sheets. The property and activities of catalysts for hydrodesulfurization (HDS) of dibenzothiophene and hydrodearomatization (HDA) of tetralin are dependent on the calcination temperature. At 300 °C, WS 3 can be well maintained, offering highly active hydrogenation sites S 2 2– and superior HDA activity. As the temperature increases up to 500 °C, WS 3 converts into WS 2 , while nickel sulfides migrate to the edge of WS 2 to form NiWS phases with high HDS activity. LDH-based presulfurized catalysts can achieve fully sulfurized and well-dispersed tungsten species even at high tungsten loadings and can retain more WS 3 even at high temperatures because of the peculiar properties of LDHs. Therefore, they show better HDS and superior HDA activities over an oxidic NiW LDH-based catalyst (LDO) and an alumina-supported NiWS presulfurized catalyst (NiWS/Al 2 O 3 ). The optimized catalyst shows 1.59 and 1.05 times higher HDS activity than LDO and NiWS/Al 2 O 3 while 2.05 and 1.77 times higher HDA activity than LDO and NiWS/Al 2 O 3 , respectively. It also shows better HDS and HDA activity for a real diesel than a NiCoMoW/Al 2 O 3 commercial catalyst.

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