Noble-metal clusters are important catalysts because of their unique structures and activities, which are associated with their metalÀmetal bonds.[1] Numerous methods have been developed to encapsulate metal clusters within porous materials or polymers to protect the clusters against sintering.[2] A common porous support is zeolite, owing to its intrinsic subnanometer pore diameters, which are similar to the size of the metal clusters and can confine and prevent the clusters from growing into big particles. This confinement allows metal clusters to activate reactants with small molecular sizes that are accessible to the pores. [3] Mesoporous silica provides an ideal support, owing to its large pore diameters, which are suitable for large-sized organic substrates and biomass derivatives.[4] Ligand-stabilized metal precursors are usually used to anchor the clusters within the mesoporous channel with a low loading of the metal.[5] Uniform mesoporous-silica-supported noble-metal clusters cannot be achieved by impregnation of the support in an aqueous solution of the metal salts because the pore diameter of mesoporous silica (> 2 nm) is larger than the size of the metal clusters. The metal clusters are easily grown into big particles with a broad size distribution.[6] The incorporation of heteroelements (Zr, Ti, Al, etc.) into mesoporous silica has been developed to disperse metal species.[7] However, some metal particles still migrate towards the outside of the support during the reduction step with hydrogen, which causes their aggregation into big particles and, hence, the blocking of the entrance to the pore channels. Therefore, substantial challenges remain towards the goal of synthesizing uniform metal clusters that are immobilized within mesoporous silica from the corresponding metal salts.Biomass becomes an increasingly important feedstock to produce fuels and chemicals for a sustainable future.[8] Furan derivatives have been identified as the key building blocks to synthesize valuable chemicals.[9] Besides its nontoxic and nonflammable properties, water is a desirable solvent because the furan derivatives are soluble under aqueous conditions.[10] Several catalysts have been developed for the hydrogenation of furan derivatives in water, but high reaction temperatures or high hydrogen pressures are required to achieve high activities because of the low aqueous solubility of hydrogen. [11] Herein, immobilized ruthenium clusters (50 Ru atoms) in nanosized mesoporous zirconium silica (MSN-Zr) were synthesized by using an impregnation method, starting from an aqueous solution of RuCl 3 . The Ru cluster catalyst showed remarkable activity for hydrogenation of furan derivatives in water at room temperature under 5 bar hydrogen pressure.MSN-Zr-x, which has a uniform hexagonal pore structure, was synthesized by modification of our previously reported two-step procedure, [12] in which x denotes the Si/Zr molar ratio (for the detailed preparation, see the Supporting Information). The morphology and pore structure are sim...

Efficient depolymerization of woody biomass to produce natural phenolic alcohols not only preserves the original structure of lignin, but also makes the depolymerization process atom-efficient. Here, high yield production of natural phenolic alcohols (38.7 wt %) from woody biomass has been achieved using a Ni/C catalyst in a methanol-water co-solvent. The Ni-based catalyst can efficiently etherify the C -OH group in lignin β-O-4 motifs under hydrogen atmosphere, which can break the hydrogen bond between the C -O oxygen and the C -OH proton to facilitate the C -O cleavage. It was reported that water can also accelerate the etherification of raw lignin with methanol through in situ formation of acid. Our results suggest that breaking the intramolecular hydrogen bonds can accelerate the C -O cleavage, keeping the original structure of lignin unchanged. This work highlights the significance of structure modification in lignin depolymerization and displays a clear potential for the valorization of whole biomass.