Preparation of indium oxide nanowires and application on photoelectrochemical water splitting

Abstract

The main goal of this dissertation is the fabrication and analysis of highly photoactive In2O3 nanowires photoelectrode in photoelectrochemical (PEC) application The In2O3 nanowires were grown using vapor-liquid-solid method on cost effective SiO2/Si template The experiment is divided into three parts： First we investigate the relation between the oxygen flow rate and the morphologies of In2O3 nanostructures The results show that indium oxide nanowires would not be preferable grown in Ar/O2 ambient The extra supply of oxygen would be harmful to growing indium oxide nanowires Based on the result we then control the growth temperature and successfully synthesize different morphologies of In2O3 nanowires at different temperature without the extra supply of oxygen It was found that XRD intensity increased as we increased the growth temperature The observations suggest that the crystalline quality of the nanowires depend on the growth temperature In the second part of our experiment we report the growth of In2O3 nanowires using a vapor phase transport method and the PEC hydrogen generation using these nanowires as PEC photoelectrode It was found that crystallinity and PEC performances of the nanowires depend strongly on the growth temperature It was also found that PEC conversion efficiencies were 0 016% 0 356% and 1 222% at zero bias voltage (VCE) for the In2O3 nanowire samples prepared at 800oC 850oC and 900oC respectively Finally we investigated the effect of C-doping on the photoelectrochemical properties of In2O3 nanowires prepared by vapor phase transport method Vapor phase transport method offers an inexpensive and simple method to introduce carbon dopants into In2O3 nanowires by merely adding dopant sources to the indium source The EDS and XPS confirmed carbon’s presence and content It was found that PEC conversion efficiencies were 1 22% and 4 199% at zero bias voltage (VCE) for undoped and C-doped In2O3 nanowire samples respectively The results suggest that C-doped In2O3 nanowires shows highly enhanced PEC activity compared with undoped In2O3 nanowires

Date of Award	2014 Jul 11
Original language	English
Supervisor	Shoou-Jinn Chang (Supervisor)