Synthesis-cum-assembly toward hierarchical nanoarchitectures

Self-assembly of nanoscale materials represents the prevailing bottom-up strategy toward constructions of nanoarchitectures with hierarchical structures and desirable functionalities. Differentiated from the synthesis-then-assembly approach which involves organization of preformed uniform nanoparticles (NPs), the synthesis-cum-assembly, where the formation and the assembly of the primary NPs occur simultaneously within the same experimental settings is endowed with inherent advantages in building functional architectures of well-defined morphologies, hierarchical structures, controllable dimensions, permanent stability and excellent processability. Current methodologies to operate synthesis-cum-assembly could be broadly divided into three major categories: (i) the process involving solid particles as both precursors and templates, such as SiO2 beads, coordination polymer colloidal particles, inorganic-organic supermolecules, metal/metal oxides; (ii) the one assisted with inertial templates such as micelles, vesicles and emulsions of various amphiphiles including surfactants, polymers and biomolecules; and (iii) the template-free case which is relatively less reported. Salient features of these methods were analyzed and compared by selecting typical studies, in order to demonstrate the working principles in each approach. This review puts emphasis upon strategies to balance the process kinetics between the chemical reactions of generating primary NPs and the physical assembly process; the various postsynthetic modifications and applications of 1D-3D endproducts gained from various synthesis-cum-assembly studies toward heterogeneous catalysis, adsorptions, electrocatalysis, lithium-ion batteries etc., are also covered, and future research directions are present as well.