Electrochemical preparation of functional nanoporous materials and their applications

Abstract

Nanoporous materials prepared by electrochemical method are promising materials for applications in catalysis, chemical, biological sensing and energy storage, owing to its high surface area and controllable porous structure with facile fabrication. This thesis describes the electrochemical fabrication of porous Nickel (pNi) and porous silicon (pSi) materials and the use of these materials as chemical and biological sensors and as supercapacitors. The first chapter provides an introduction to electrochemically fabricated pNi and pSi materials and the applications of these porous materials. The second chapter describes the fabrication method of the novel periodic pNi metallic structure by waveform-modulated electrodeposition of Ni-Cu alloy and selective etching of Cu metal. The pNi metallic structure features vertically oriented nanochannels with periodically corrugated channel walls. This structure was then subsequently partially oxidized to give an optical response, and demonstrate its ability as an ethanol vapor sensor. The third chapter further demonstrates this periodic pNi metallic structure as an electrode scaffold for supercapacitors. The pNi scaffold was coated with NiIIIO(OH) via anodic electrodeposition to obtain NiIIIO(OH)/Ni coaxial nanocomposite and serves as high performance supercapacitor. The forth chapter describes a new type of pNi metallic array - nanovolcano arrays which features a highly ordered, hexagonally arranged concave nanobowls decorated with triangular nanopores at their interstices. After coating with Ag, the nanovolcano arrays serve as a high-performance substrate for surface enhancement Raman spectroscopy (SERS) measurement. The fifth chapter demonstrates a porous siliconcarbon composite (pSi-C) as a Label-free optical biosensor which shows excellent stability in an aqueous buffer solution (pH 7.4 or 12) and higher sensitivity compared to porous TiO2 and porous Al2O3 optical biosensors. The sixth chapter is the thesis conclusion which summarizes the works of this thesis.

Date of Award	15 Jul 2013
Original language	English
Awarding Institution	City University of Hong Kong
Supervisor	Yangyang LI (Supervisor)