A novel reverse microemulsion strategy was developed to asymmetrically encapsulate metal-oxide nanoparticles in silica by exploiting the self-catalytic growth of aminosilane-containing silica at a single surface site. This strategy produced various colloidal Janus nanoparticles, including Au/Fe3O4@asy-SiO2, which were converted to an Au-containing silica nanosphere, Au@con-SiO2, by reductive Fe3O4 dissolution. The use of Au@con-SiO2 as a metal-growing nanoreactor allowed the templated synthesis of various noble-metal nanocrystals, including a hollow dendritic Pt nanoshell which exhibits significantly better electrocatalytic activities for the oxygen reduction reaction than commercial Pt/C catalysts.

Designing and synthesizing noble metal nanostructures with tunable porosity and nanoscopic intricacies is crucial for highly augmented surface properties and as gateway to the wide range of applications. Here, we develop a pore-engineered nanoreactor (PENR)-based approach toward the synthesis of porous platinum nanodendrites (PtNDs) of “yolk-in-shell” and “shell-in-shell” morphologies and with tunable nanoscale porosity. In our strategy, first, various silica-based PENRs with variable porosity and each containing a single Au seed were synthesized by a successive base-catalyzed condensation reaction of a mixture of aminoalkyl-organosilanes in a one-pot reverse-microemulsion strategy, followed by selective silica hydrolysis reactions. The key strategy involved the addition of different silanes at different stages of silica condensation, rendering appropriately located fragile and rigid silica regions in silica nanospheres, which were conveniently carved into a “termite-nest” like structure with amine-rich nanocompartments. Further, growth of different PtNDs was chemically guided by metallophilic amine groups through the pores and channels of nanoreactors, and overall morphologies of PtNDs were highly customizable by the different confined nanospaces inside PENRs.

The present study proposes a methodology to extend the utility of solid-state reactions to a synthetic route for producing a high-diversity pool of nanocrystals (NCs) by circumventing the problematic sintering of nanoparticles at high temperatures. For this purpose, nanometer-scale-confined NC formations/transformations were investigated using specifically designed SiO 2 nanospheres with a radially differentiated core@shell structure as a reaction medium. The core of the SiO 2 medium was modified by aminosilanes, thus providing binding sites for the metal ions and enabling pore creation through thermochemical treatment. This hindered the outward diffusion of fast-moving tiny species initially generated within the tens of nanometers-sized medium. The entire evolution process of Pd NCs during the high temperature reaction was confined within the SiO 2 nanosphere, which transforms from the aminecontaining nanosphere, Pd 2+ /SiO 2 (NH 2 ), to a hollow nanosphere, Pd@h-SiO 2 . This nanoscale confinement strategy was applicable to the first-row transition metals with high diffusivity in SiO 2 medium. Accordingly, M 2+ /SiO 2 (NH 2 ) 2 (M = Co, Ni, or Cu) and (Pd 2+ /M 2+ )/SiO 2 (NH 2 ) 2 were thermally developed into

Interest and challenges remain in designing and synthesizing catalysts with nature-like complexity at few-nm scale to harness unprecedented functionalities by using sustainable solar light. We introduce "nanocatalosomes"-a bioinspired bilayer-vesicular design of nanoreactor with metallic bilayer shell-in-shell structure,h aving numerous controllable confined cavities within few-nm interlayer space,customizable with different noble metals.T he intershell-confined plasmonically coupled hot-nanospaces within the few-nm cavities play apivotal role in harnessing catalytic effects for various organic transformations,a sd emonstrated by "acceptorless dehydrogenation", "Suzuki-Miyaura cross-coupling" and "alkynyl annulation" affording clean conversions and turnover frequencies (TOFs) at least one order of magnitude higher than state-of-the-art Au-nanorod-based plasmonic catalysts.T his work paves the wayt owardsn ext-generation nanoreactors for chemical transformations with solar energy.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Multifunctionalized porous catalytic nanoarchitectures are highly desirable for a variety of chemical transformations; however, selective installation of different catalysts with spatial and functional precision working synergistically and predictably, is highly challenging. Here, a synthetic strategy is developed toward the customizable combination of orthogonally reactive metal nanocrystals within interconnected carbon‐cavities as a compartmentalized framework by employing aminated‐silica‐directed thermal solid‐state nanoconfined synthesis of metal nanocrystals and endotemplating concomitant carbonization‐mediated interlocking, as key processes. The main advantage of the strategy is the facility to choose any combination of metals, which can be further employed according to the desired application. The strategically synthesized compartmentalized multifunctional catalytic architectures of Pd‐Pt@Com‐CF regulate the O2‐mediated selective cascade oxidation reaction converting alcohol to acid with high yield and selectivity; and another Pt‐Ir@Com‐CF platform is demonstrated as a bifunctional electrocatalyst for oxygen reduction/evolution reactions.