Seminar

ENGINEERING HDR SEMINAR SERIES (35/2015): Photoelectrocatalytic Conversion of Wastewater into Renewable Hydrogen Energy and Clean Water Resources: From nanostructured materials synthesis to photoreactor design, modelling and optimis

Ms. Phuan Yi Wen


Date: 2015-07-14
Time: 14:30 to 15:30
Venue: Engineering Meeting Room 2, 5-4-03


Abstract

Rapid industrialisation in the past century has unarguably enhanced the quality of life of mankind. However, this comes at an expense of energetic and environmental related problems. For instances, water pollution and scarcity, and potential energy shortage crisis. From the past-to-present, considerable efforts have been devoted to the technological advancements in order to resolve the water-energy problems. Recently, the photoelectrocatalytic (PEC) process has emerged as an innovative, sustainable and environmental friendly technological solution to simultaneously convert wastewater into renewable hydrogen energy and clean water resources. With the aid of semiconductor photocatalyst, organic-laden wastewater can be converted into hydrogen energy and clean water resources in order to debottleneck the water-energy nexus. Among all, hematite has emerged as a promising semiconductor photocatalyst material due to its abundance, stability and high absorption into visible light spectrum. However, the PEC performance was limited by its low-electron mobility, short-hole diffusion length and required large overpotential for water oxidation. Recent studies have shown that by controlling the surface morphology and employing advanced surface treatments on hematite can significantly enhance the PEC performance. Thus, the main aim of this study was to synthesize high-performance nanostructured hematite thin films on photoanode for application in PEC process. Firstly, nanostructured hematite thin films were synthesized by using cathodic electrodeposition method without doping or surface modification. This was done by systematically studied the effect of electrodeposition conditions on the size, morphology and film thickness of hematite. Further enhancement in PEC performance was performed by incorporating metals and non-metals dopants, which will help to improve the separation efficiency of charge carriers. Both Pt and Ni dopants play a vital role in facilitating the photogenerated charge transfer and separation as well as improving the conductivity of hematite. Secondly, different PEC reactor designs were modelled and optimised by using computational fluid dynamics (CFD). Preliminary CFD modelling enabled understanding on the flow distribution and geometrical effects on the performance of PEC reactors. Further improvement on the CFD model was carried out to model different PEC reactor designs. Results showed that the performance of the PEC reactor anodic chamber was dependent on the benzoic acid concentration, light irradiance reaching the photoanode surface, reactor configurations and hydrodynamics condition. A lab-scale dual-function PEC reactor was fabricated based on the CFD model PEC reactor design and it will be used for subsequent integration of the successfully-assembled hematite photoanode for validation purpose.

About the Speaker

Ms. Phuan Yi Wen received her B.Eng (Hons 1A) in Chemical Engineering from Monash University Malaysia in 2013. She continued her postgraduate studies in 2013 under the supervision of Dr. Chong Meng Nan and A/Prof Chan Eng Seng. Her research focuses on the electrochemical synthesis and modification of nanostructured hematite (α-Fe2O3) as an efficient semiconductor photocatalyst material for photoanode application in photoelectrocatalytic (PEC) reactor for clean energy and water production.