Templated electrodeposition of functional nanostructures: nanowires, nanotubes and nanocubes
Prof. dr. ir. J.E. ten Elshof
This thesis is entitled “Templated electrodeposition of functional nanostructures: nanowires, nanotubes and nanocubes”. Templated electrodeposition is the synthesis technique that was used throughout this thesis, and it comprises the use of a template with specific shape and dimensions for the formation of different types of nanostructures. Throughout this thesis, three different nanostructures were made: nanowires (Chapters 2 to 6), nanotubes (Chapters 2 and 5) and nanocubes (Chapters 7 and 8). Since electrodeposition can be used for the synthesis of many different types of materials, like metals (Chapters 2-5, 7, 8), metal oxides (Chapters 2, 4-7) and metal sulphides (Chapter 8), different types of functionalities can be given to these nanostructures. Throughout this thesis, photocatalytic H2 formation was the functionality that was studied most (Chapters 2, 4-7), but electrocatalytic H2 formation (Chapter 8) and magnetic properties (Chapter 3) were also studied.
In Chapter 1, a theoretical introduction into (templated) electrodeposition and photocatalysis is given. Chapter 2 describes the most essential experimental procedures that were used throughout this thesis. In Chapter 3, it is shown that the galvanic replacement reaction can be suppressed by increasing the overpotential used for electrodeposition of the noble metal. Chapter 4 presents an axially segmented nanowire system containing Ag and ZnO segments that finds application in photocatalytic water splitting. In Chapter 5, TiO2 nanotubes are demonstrated that were formed by the electrochemically induced sol-gel method. Chapter 6 presents a photocatalytic nanowire system in which a p-n photoelectrochemical diode is responsible for the photocatalytic activity instead of a Schottky barrier. Chapter 7 presents a method for the formation of nanocubes via templated electrodeposition inside a template containing a cubic hole pattern. In Chapter 8, Au nanocube structures with a PMMA core made by a combination of NIL and sidewall deposition were used as an alternative template for deposition of MoS2, Pt and Ni nanocube structures.