Supported gold catalysts were investigated in the selective gas phase hydrogenation of 1,3-butadiene in an excess of propene (0.3% butadiene, 30% propene and 20% hydrogen), in order to simulate the process required for the purification of industrial alkenes streams to prevent poisoning of the polymerisation catalysts used for polyalkene production. Gold catalysts containing small gold particles (between 2 to 5 nm in average) are less active than commercial palladium catalysts, but they are much more selective. Under our experimental conditions, 100% of butadiene can be converted at ≈170°C into 100% butenes with 1-butene as the main product, and with only very small amount of alkanes formed (≈100 ppm). The absence or presence of propene does not drastically modify the rate of hydrogenation of butadiene. Parameters directly related to the nature of the gold catalysts were also investigated. For a given preparation method (deposition-precipitation with urea (DPU)), gold particle size and gold loading, the nature of the oxide support (alumina, titania, zirconia, ceria) does not influence the gold reactivity. The variations of gold particle size and gold loading do not induce changes in the TOF (expressed per surface gold atoms). The method of preparation has an influence when it leaves chlorine in the samples (impregnation in excess of solution and anionic adsorption). In such a case, the gold catalysts are less active.

A heterostructure constructed by modification of perylenetetracarboxylic diimide (PDI) upon MOFs for visible-light-driven H ₂ O ₂ production from H ₂ O and O ₂ .

The introduction of a secondary ligand into titanium-based metal–organic frameworks for visible-light-driven photocatalytic H₂O₂ production from dioxygen reduction.

This review focuses on the chemical methods used to prepare supported bimetallic heterogeneous catalysts, i.e., bimetallic nanoparticles deposited on a support. The review is limited to the preparation of gold-based bimetallic catalysts and moreover to bimetallic nanoparticles supported on powder inorganic supports, i.e., on the surface or in the porosity, and not on model supports such as single crystals.

This article is about the reaction of selective hydrogenation of 1,3-butadiene performed in an excess of alkenes (propene/butadiene ratio = 100) over supported gold catalysts, so as to mimic the conditions of purification of light alkenes (C4 cuts) from the presence of impurities (highly unsaturated compounds, 1–3%). Gold was found highly selective (close to 100%, no propane or butane formation) for the hydrogenation of butadiene to butenes at 100% conversion of butadiene. The influence of the concentrations of the various reactants, i.e. hydrogen, butadiene and propene, on the rates of butadiene and propene hydrogenation was investigated, and the apparent reaction orders were deduced from the dependence of rate on partial pressure in the gas phase. The reason for the high selectivity of gold catalysts is that the reaction of hydrogenation of alkenes occurs at much higher temperature (0.1% conversion at 300°C) than that of selective hydrogenation of butadiene (100% at T <170°C). Moreover, the presence of propene has only a limited influence on the reaction of butadiene hydrogenation, while butadiene has no influence on propene hydrogenation; the two reactions of hydrogenation hardly influence each other. Hydrogen dissociation is the rate limiting step of the reaction (partial order of 0.7 and 1 with respect to H₂ for butadiene and propene hydrogenation, respectively), responsible for the low activity of gold. The catalytic properties of gold were compared to those of palladium-based catalysts, and reasons for their different behaviour were discussed.