PdAu alloy nanoparticles supported on nitrogen-doped carbon black as highly active catalysts for Ullmann coupling and nitrophenol hydrogenation reactions.

Noble metal-based catalysts have been proven to be active for catalytic organic reactions. The selectivity and conversion can be improved by integration with proper carrier materials, and further modulated by tuning the composition as well as the electronic structure of the active noble metals. Compared with unsupported monometallic catalysts, the synergistic interactions between neighboring metals and the combined effects between the carrier materials and the active components often give rise to positive influences on the enhancement of the catalytic efficiency and selectivity. In this work, we report a facile process for the fabrication of nitrogen-doped carbon black (NCB) supported PdAu bimetallic nanoparticles (NPs) with a uniform dispersion and narrow size distribution. The PdAu/NCB catalyst with a Pd/Au mole ratio of 1/1 shows the highest activity towards both Ullmann coupling reactions of aryl halides and the hydrogenation reaction of nitrophenols. Moreover, this bimetallic catalyst also exhibits a superior recycling durability to that of monometallic Pd/NCB and Au/NCB catalysts. The enhanced catalytic performance of the bimetallic catalyst is mainly due to the large BET specific surface area (125.45 m 2 g -1 ) and the synergy between the individual components of the catalyst.