Precise Construction of Pd Superstructures with Superlattices for Solar-Driven Organic Transformation

Precisely controlling the spatial arrangement of nanostructures offers unique opportunities for tuning physical and chemical properties, however, it remains a great challenge due to the lack of effective synthetic methods. Herein, we present a wet-chemistry strategy for the synthesis of three-dimensional (3D) Pd superstructures (Pd SSs) by manipulating the growth kinetics. The strategy consists of two steps including (1) the formation of tetrahedron-shaped Pd nanocrystal core and (2) the growth of four legs on each tip of the core. Interestingly, each leg can be built from one, two, or three arrowhead-like Pd nanocrystals. Moreover, superlattices that associate with Pd vacancies are extensively present in Pd SSs, providing active sites for reactant molecule adsorption and activation. The Pd SSs exhibit an excellent catalytic performance toward the oxidation of o-phenylenediamine (OPDA) under visible and near-infrared (NIR) light illumination. Both theoretical and experimental results demonstrate that the superior photocatalytic activity of Pd SSs benefits from the well-ordered 3D architecture, unique superlattice properties, high-index facets, and large local electric field enhancement. This research sheds new light on the rational design and precise construction of 3D nanostructures, with potential promising applications in the fields of catalysis, nanotechnology, and biotechnology.