In this work, we present a detailed study concerning the evaluation of the metal-support interaction in high activity gold catalysts for CO oxidation. Using the colloidal deposition method, model catalysts were prepared, which allow the isolation of the effect of the support on the catalytic activity. Prefabricated gold particles were thus deposited on different support materials. Since the deposition process did not change the particle sizes of the gold particles, only the influence of the support could be studied. TiO2, Al2O3, ZrO2, and ZnO were used as support materials. Catalytic tests and high resolution transmission electron microscopy clearly show that the support contributes to the activity. However, our results are not in line with the distinction between active and passive supports based on the semiconducting properties of the oxidic material. The most active catalysts were obtained with TiO2 and Al2O3, while ZnO and ZrO2 gave substantially less active catalysts. Furthermore, the effect of other important parameters on the catalytic activity (i.e., particles size distribution, calcination temperature, and aging time for a Au/TiO2 catalyst) has also been studied. Using this preparation route, the catalysts show high-temperature stability, size dependent activity, and a very good long-term stability.

The synthesis of 2,5-dimethylfuran (DMF) from 5-hydroxymethylfurfural (HMF) is a highly attractive route to a renewable fuel. However, achieving high yields in this reaction is a substantial challenge. Here it is described how PtCo bimetallic nanoparticles with diameters of 3.6 ± 0.7 nm can solve this problem. Over PtCo catalysts the conversion of HMF was 100% within 10 min and the yield to DMF reached 98% after 2 h, which substantially exceeds the best results reported in the literature. Moreover, the synthetic method can be generalized to other bimetallic nanoparticles encapsulated in hollow carbon spheres.

Magnetic, highly porous ordered carbon of the CMK‐3 and CMK‐5 type and with pure carbon or carbon–nitrogen framework were nanoengineered by a sequence of bulk manipulation steps. The materials can be used as efficient magnetic adsorbents (see picture) or catalysts, but applications going far beyond these can be envisaged.

Mesostructured metal oxides whose framework structures are engineered from materials other than silica make attractive research subjects. However, direct synthesis of these kinds of mesoporous materials using surfactants is quite difficult because, compared to silica, the surfactant/oxide composite precursors are often more susceptible to lack of condensation, redox reactions, or phase transitions accompanied by thermal breakdown of the structural integrity.[1] The nanocasting method for carbon, [2] pioneered by the group of Ryoo, [3] is an attractive alternative to the cooperative assembly routes, but using it to prepare non-carbon frameworks seems to be difficult. Previously, focus has mainly been on the creation of noble-metal replicas of small sections of the pore systems, which are then used to visualize their connectivity. [4] In this work we have explored the possibility of synthesizing frameworks of novel composition using silica-based templates. Spinel-type cobalt oxide (Co 3 O 4 ) was selected as a model because it is potentially useful for applications in catalysis, sensors, magnetic materials, and energy storage. For instance, Poizot et al. [5] proposed nanometer-sized transition-metal oxides as a new class of anode materials for lithium-ion batteries. Among them, cobalt oxides demonstrated the best electrochemical properties as lithium storage materials in lithiumion cells. Zhao's group has recently been successful in using microwave-digested (MWD) mesoporous silica (specifically, the two-dimensional hexagonal mesoporous silica, SBA-15, and the three-dimensional caged mesoporous silica, SBA-16) to synthesize nanowires and nanospheres of different metal oxides.[6] We show here that it is possible to create cubic Ia3dCo 3 O 4 using vinyl-functionalized, ordered, mesoporous silica [7] as a template, and demonstrate that the bulk antiferromagnet shows weak ferromagnetism at low temperatures. Following the synthesis procedure given in the Experimental section, a mesoscopically ordered array of Co 3 O 4 was obtained. Figure 1a shows the low-angle X-ray diffraction COMMUNICATIONS