Supported Au nanoparticles (NPs) prepared by colloid deposition method were well characterized, and their catalytic performance was tested for chemoselective reduction of a nitro group of substituted nitroaromatics by H 2 . Systematic studies on the effects of NPs size and support show small size of Au NPs, and acid-base sites of supports are required for high activity. The Au/Al 2 O 3 catalyst with Au particle size of 2.5 nm selectively hydrogenates a nitro group in the presence of various other reducible functional groups, and it shows higher intrinsic activity than the state-of-the-art catalyst (Au NPs on TiO 2 ). In situ FTIR studies provide a reaction mechanism, which explains fundamental reasons of the observed structure-activity relationship. Cooperation of the acid-base pair site on Al 2 O 3 and the coordinatively unsaturated Au atoms on the Au NPs are responsible for the H 2 dissociation to yield a H + /Hpair at the metal/support interface. High chemoselectivity could be attributed to a preferential transfer of the H + /Hpair to the polar bonds in the nitro group as well as a preferential adsorption of nitroaromatics on the catalyst through the nitro group.

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A series of silica‐supported silver catalysts with various Ag loading (3–30 wt %) and different treatment (oxidation and subsequent reduction by H2) were prepared, and their local structures were characterized by extended X‐ray absorption fine structure (EXAFS) analysis. In oxidized catalysts, silver were mainly present as small nanoparticles with surface oxygen atoms, and the number of surface oxygen atoms decreased with increased silver loading. The H2 reduction of these samples resulted in a removal of the surface oxygen atoms. The structure–activity relationship was studied for the alkylation of anisole with benzyl alcohol and styrene. AgI oxide, AgI ion, bulk silver metal, and silica‐supported silver nanoparticles were non‐active species. In contrast, silica‐supported silver nanoparticles with the surface oxygen atoms acted as an effective heterogeneous catalyst for the alkylation of arenes with alcohols and styrenes. Kinetic studies in alkylation of anisole with alcohols showed that the cleavage of the α‐CH bond of alcohol was the rate‐limiting step. It is proposed that the surface oxygen adjacent to the silver surface atoms plays an important role in the dissociation of the α‐CH bond.