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Hybrid organic-lead halide perovskites exhibit remarkable properties as semiconductors and light absorbers. Here, we report the formation of silsesquioxane-lead halide hybrid layered perovskites. We prepared silsesquioxane with a cubic cage-like structure and fabricated hybrid silsesquioxane-lead halide layered perovskites in a self-assembled manner. It is demonstrated that the silsesquioxane maintain their cage-like structure between lead halide perovskite layers. The silsesquioxane-lead halide perovskites also show excitonic absorption and emission in the visible light region similar to typical lead halide layered perovskites.

A series of ZrO2 catalysts supported on mesoporous SBA-15 silica were synthesized and examined as catalysts in the production of γ-valerolactone (GVL) from biomass-derived levulinic acid and its esters via a catalytic transfer hydrogenation (CTH) using several alcohols as hydrogen donors. Among the catalysts examined, ZrO2 supported on high-surface-area SBA-15 silica bearing highly-dispersed zirconium species exhibited the highest catalytic activity, of which reaction rate was 1.7 times higher than that of the conventional bulk ZrO2 catalyst. Zr K-edge XAFS analysis revealed that Zr4+-oxide species with a low-coordination state anchored on silica surface is the dominant active species. Such a Zr species efficiently converted levulinic acid and its esters to GVL (∼95% yields) under mild reaction conditions (150 °C, 1.0 MPa Ar), and was reusable over multiple catalytic cycles without significant loss of catalytic performances. Comparative experiments, combined with detailed characterizations using NH3/CO2-TPD and in-situ FTIR, proposed a plausible reaction mechanism where basic Zr OH site triggers the CTH reaction involving a six-member ring transition state.

Production of γ-valerolactone (GVL) from levulinate esters and several alcohols as hydrogen donors via a catalytic transfer hydrogenation (CTH) process was performed over supported ruthenium hydroxide catalysts. Among the catalysts examined, Ru(OH)x supported on high-surface-area, anatase TiO2 containing highly-dispersed ultrasmall Ru(OH)x nano-clusters was found to be the most active catalyst, which converted levulinate esters to GVL in an almost quantitative yield under mild reaction conditions with low catalyst loading. Addition of heterogeneous bases could afford a faster reaction rate in GVL production by accelerating the following intramolecular dealcoholation step. The catalyst was reusable over repeated catalytic cycles without loss of catalytic performance, making this material a potential candidate for efficient GVL production under ambient reaction conditions.

Esterification of levulinic acid with ethanol to produce ethyl levulinate was examined by using sulfated Si-doped ZrO 2 solid acid catalysts with enlarged surface areas and the relationships between the structural properties and catalytic performances were investigated. Structures of the catalysts were verified by XRD, nitrogen physisorption, FE-SEM, UV–vis and FTIR measurements. Acidity of the catalysts that substantially affect the catalytic activity was evaluated by NH 3 -TPD measurement. Incorporation of Si atom into the lattice structure of ZrO 2 (up to 30 mol% Si per Zr atom) afforded high-surface-area SiO 2 -ZrO 2 mixed oxides, and their sulfated forms provided increased numbers of sulfate anions and the associated acid sites. Several distinct correlations were found between the structural properties/acidities and catalytic activities, which suggested that (i) the number of accessible active acid sites and (ii) the accessibility of the organic reactants to the active sites play crucial roles in determining the overall activity. Among the catalysts tested, sulfated Si-doped ZrO 2 with optimum Si content (5.0–10 mol% Si per Zr) was found to be the best catalyst, the activity of which was far superior to that of the conventional sulfated ZrO 2 . In addition, direct conversion of cellulosic sugars (glucose and fructose) into levulinate esters was also examined, in view of their practical applications in acid-catalyzed biomass conversion processes.

Levulinic acid and its esters, important intermediate chemicals produced from biomass resources, were converted to γ-valerolactone via a catalytic transfer hydrogenation process over silica-support...