Rational Electrochemical Design of Cuprous Oxide Hierarchical Microarchitectures and Their Derivatives for SERS Sensing Applications

Abstract Rational morphology control of inorganic microarchitectures is important in diverse fields, requiring precise regulation of nucleation and growth processes. While wet chemical methods have achieved success regarding the shape‐controlled synthesis of micro/nanostructures, accurately controlling the growth behavior in real time remains challenging. Comparatively, the electrodeposition technique can immediately control the growth behavior by tuning the overpotential, whereas it is rarely used to design complex microarchitectures. Here, the electrochemical design of complex Cu₂O microarchitectures step‐by‐step by precisely controlling the growth behavior is demonstrated. The growth modes can be switched between the thermodynamic and kinetic modes by varying the overpotential. Cl⁻ ions preferably adhered to {100} facets to modulate growth rates of these facets is proved. The discovered growth modes to prepare Cu₂O microarchitectures composed of multiple building units inaccessible with existing methods are employed. Polyvinyl alcohol (PVA) additives can guarantee all pre‐electrodeposits simultaneously evolve into uniform microarchitectures, instead of forming undesired microstructures on bare electrode surfaces in following electrodeposition processes is discovered. The designed Cu₂O microarchitectures can be converted into noble metal microstructures with shapes unchanged, which can be used as surface‐enhanced Raman scattering substrates. An electrochemical avenue toward rational design of complex inorganic microarchitectures is opened up.