Copper-supported mesoporous carbon nanocatalysts (Cu/FDU-15) were synthesized using an easy and convenient one-pot soft-template method for low-overvoltage CO electroreduction. TEM imaging revealed the presence of large Cu nanoparticles (diameter 140 nm) with Cu O nanoparticles (16 nm) as an additional phase. From the electron tomography observations, we found that the copper particles were placed inside and on the exterior surface of the porous FDU-15 support, providing an accessible surface for electrocatalytic reactions. CO electrolyses showed that the mesostructured Cu/FDU-15-350 cathode materials were active towards CO conversion to formic acid with 22 % Faradaic efficiency at a remarkably low overpotential of 290 mV, hydrogen being the only side-product. The catalyst's activity correlates to the calculated metallic surface area, as determined from a geometrical model, confirming that the mesoporous channels act as a diffusion path for the CO molecule, and that the whole Cu surface is accessible to CO , even if particles are entrapped in the carbon matrix.

International audienceA simple, direct and environmentally-friendly one-pot preparation of a palladium-containing mesoporous carbon (Pd@MC) from a cheap, non-hazardous and easily accessible biopolymer (tannin) as a carbon precursor, Pluronic (R) F127 surfactant as a pore structuring agent and a palladium salt is reported. This material has the peculiarity to have palladium nanoparticles entrapped in irregular voids connected to the worm-like mesoporous network limiting palladium leaching while keeping good access to the reactants. It was successfully used as a catalyst for ligand-free Suzuki-Miyaura couplings of aryl bromides in a green solvent (propane-1,2-diol) in the presence of extremely low amounts of supported palladium (usually 30 mu equiv.). It is noteworthy that almost palladium-free products (containing less than 1.5 mu equiv. of precious metal) can be obtained. The possibility to reuse the catalyst was also ascertained