Reversible self-assembly of nanoparticles into ordered structures is essential for both fundamental study and practical applications. Although extensive work has been conducted, the demand for simple, cheap, reversible, and versatile ordering methods is still a central issue in current nanoscience and nanotechnology. Here we report a reversible and precise self-assembly of nanoparticles through a linker-free and fast approach by manipulating the interparticle forces, e.g., van der Waals (VDW) force and electrostatic force. Because VDW force is nondirectional, an oriented interaction is achieved to induce the directional binding of nanoparticles utilizing the Janus nanostructure. An effective sol-gel approach has been developed to synthesize metal-organosilica Janus nanoparticles. Dimers and trimers can be obtained by tuning the steric hindrance. After assembly, "hot-spots" can be generated between adjacent nanoparticles, and dramatic enhancement has been observed in surface-enhanced Raman scattering. The present strategy overcomes several limitations of existing approaches and allows the controlled assembly of small particles into various structures.

Water electrolysis using renewable energy inputs is being actively pursued as a green route for hydrogen production. However, it is limited by the high energy consumption due to the sluggish...

Janus nanostructures that possess two or more distinct components and surface functions have attracted more and more attention. Here, we present a seed-shape defined growth mechanism for the preparation of anisotropic Janus nanostructures, in which the shape of periodic mesoporous organosilica (PMO) is determined by the shape of Au nanoparticles. Various shaped Au@PMO composite nanostructures, such as rods, spheres, and plates, are prepared based on this general growth mechanism. By adjusting the reaction parameters (temperature, surfactant), various shaped AuNR@PMO Janus nanostructures, including horsebean- and fingernail-like nanostructures, have been successfully prepared. We also demonstrate the potential applications of such composite nanostructures. As an example, the as-prepared rod-like Janus Au@PMO nanostructures show great performance in chemo-photothermal combination therapy because of the excellent photothermal effect of Au nanorods and the high surface area of PMO nanorods. This research may open a new direction to the controllable synthesis and practical application of dedicated nanostructures with desired properties.

A hybrid catalyst with integrated single-atom Ni and nanoscale Cu catalytic components is reported to enhance the C−C coupling and ethylene (C 2 H 4 ) production efficiency in the electrocatalytic CO 2 reduction reaction (eCO 2 RR). The single-atom Ni anchored on high-surface-area ordered mesoporous carbon enables high-rate and selective conversion of CO 2 to CO in a wide potential range, which complements the subsequent CO enrichment on Cu nanowires (NWs) for the C−C coupling to C 2 H 4 . In situ surface-enhanced infrared absorption spectroscopy (SEIRAS) confirms the substantially improved CO enrichment on Cu, once the incorporation of single-atom Ni occurs. Also, in situ X-ray absorption near-edge structure (XANES) demonstrates the structural stability of the hybrid catalyst during eCO 2 RR. By modulating hybrid compositions, the optimized catalyst shows 66% Faradaic efficiency (FE) in an alkaline flow cell with over 100 mA•cm −2 at −0.5 V versus reversible hydrogen electrode, leading to a five-order enhancement in C 2 H 4 selectivity compared with single-component Cu NWs.