Despite the enormous application potential, methods for conformal few-atomic-layer deposition on colloidal nanocrystals (NCs) are scarce. Similar to the process of lamination, we introduce a “confine and shine” strategy to homogeneously modify the different surface curvatures of plasmonic NCs with ultrathin conformal layers of diverse catalytic noble metals. This self-limited epitaxial skinlike metal growth harvests the localized surface plasmon resonance to induce reduction chemistry directly on the NC surface, confined inside hollow silica. This strategy avoids any kinetic anisotropic metal deposition. Unlike the conventional thick, anisotropic, and dendritic shells, which show severe nonradiative damping, the skinlike metal lamination preserves the key plasmonic properties of the core NCs. Consequently, the plasmonic–catalytic hybrid nanoreactors can carry out a variety of organic reactions with impressive rates.

Synthesis and stabilization of ultrasmall metal nanocrystals at high temperature have always been challenging due to their self‐aggregating behavior. Here, we introduce a strategy to synthesize a cluster of tiny metal nanocrystals (~3 nm) inside a hollow carbon shell as yolk@shell‐type architecture following a metal‐coordination‐based nanocrystal stabilization at high temperature (500 °C). The successful catalytic reduction of 2‐amino‐4‐nitrophenol demonstrates the efficiency of such nanoreactor in chemical transformation. Further adaptation of this strategy helps in synthesizing bimetallic (Au/Pt, Au/Pd, and Au/Ru) nanocrystals, which unfolds the possibilities to design advanced new‐generation catalysts.

Silicon nanostructures (SiNSs) can provide multifaceted bioapplications; but preserving their subhundred nm size during high‐temperature silica‐to‐silicon conversion is the major bottleneck. The SC‐SSR utilizes an interior metal‐silicide stratum space at a predetermined radial distance inside silica nanosphere to guide the magnesiothermic reduction reaction (MTR)‐mediated synthesis of hollow and porous SiNSs. In depth mechanistic study explores solid‐to‐hollow transformation encompassing predefined radial boundary through the participation of metal‐silicide species directing the in‐situ formed Si‐phase accumulation within the narrow stratum. Evolving thin‐porous Si‐shell remains well protected by the in‐situ segregated MgO emerging as a protective cast against the heat‐induced deformation and interparticle sintering. Retrieved hydrophilic SiNSs (<100 nm) can be conveniently processed in different biomedia as colloidal solutions and endocytosized inside cells as photoluminescence (PL)‐based bioimaging probes. Inside the cell, rattle‐like SiNSs encapsulated with Pd nanocrystals can function as biorthogonal nanoreactors to catalyze intracellular synthesis of probe molecules through C‐C cross coupling reaction.

Plasmonically coupled nanoreactors capable of harnessing light energy and efficiently transforming it to perform chemical reactions are in significant demand in the field of catalysis. The development of unique solution-phase synthesis techniques for engineering intricate nanoarchitectures by introducing multiple functionalities can dramatically improve the efficacy of these nanostructures. In this context, the precise modulation of the nanostructural features and the integration of other components with the plasmonic nanoparticles within an isolated nanoconfined reaction environment is the current state of the art for their synthesis. This account highlights our achievements in designing different synthesis strategies and elucidating the mechanistic pathways involved in the development of plasmonically integrated nanoreactors. The range of applications of these plasmonic nanoreactors, which employ plasmon-induced energy for catalytic transformations, is also discussed.