Silver-Free Synthesis of Concave Au Nanocubes with Enhanced Activity Towards Electro-Oxidation of Ethanol: Experimental and Theoretical Studies

Graphical For the first time, gold (Au) concave nanocubes are generated in high uniformity via a silver(Ag)-free seeded growth. Due to the advantage in pure element, they are serving as an ideal research model to investigate the exact contribution role of crystal facet in electrocatalysis. Using ethanol oxidation reaction as a model reaction, both experimental and theoretical evidences are provided. We report a silver-free synthesis of gold (Au) concave nanocubes (CNCs) that involves the direct deposition of Au atoms over spherical Au seeds under well-controlled reaction kinetics and surface capping. The elementally-pure composition makes them ideal research candidate towards validating structural advantage of concave surface in electrocatalytic oxidation of ethanol. In particular, the as-obtained Au CNCs exhibited an enhanced specific activity and reaction kinetics, but weakened long-term stability, as compared to quasi-spherical counterparts. Theoretical simulations suggest that the high-index planes represent a high catalytic performance for ethanol oxidation. The current work offers an effective synthetic strategy that successfully excludes the necessary and wide use of Ag + ions in controlled synthesis of pure Au nanocrystals with a concave cubic shape, shedding light on the rational design of fuel cell electrocatalyst from the perspective of crystal facet effect.