Rapid synthesis of concave gold nanocubes with tunable indentations and high index facets for enhanced catalytic performance

[Display omitted] •Concave gold nanocubes (CGNs) are rapidly made by ascorbic acid (AA) and H2O2.•AA causes Au0 deposition on {111} facets, while on {100} facets for H2O2.•The induced confined growth competition accounts for morphological control.•CGNs with {730} facets exhibit a higher catalytic ability, with a distinct kinetic. Precise control of morphology is crucial for achieving sophisticated properties and advanced applications of nanomaterials. Among different shapes, concave nanomaterials have emerged as a novel class of unconventional materials with superior properties in comparison to their convex counterparts, owing to abundant atomic steps and kinks. Here, we report rapid (10 min) one-pot synthesis of concave gold nanocubes (CGNs) with tunable indentations and high-index facets, using a combination of ascorbic acid (AA) and H2O2. The synthesis of CGNs involved the reduction of Au3+to Au+by H2O2under alkaline conditions, followed by initiating CGN formation upon the addition of AA. Cyclic voltammetry scanning confirmed that AA and H2O2 co-participate in the reduction of Au+. The concentrations of H2O2and AA were precisely controlled to adjust the indentation and high-index facets, such as {730}, {610}, {310}, {830}, etc. The concave structures of CGNs were formed due to Au0deposition on {111} facets at the tips for AA and {100} facets at the surface center for H2O2. Remarkably, the typical CGNs with {730} facets exhibited higher catalytic activity towards the reduction of nitrophenol by NaBH4than many other Au nanomaterials, with an unusual kinetic profile, i.e., an increasing reaction rate.