The authors would like to express their appreciation to
the Joint Graduate School of Energy and Environment
(JGSEE) and the Thailand Research Fund (TRF) for
providing financial support in this study. The authors also
wish to acknowledge Mr. Atikom Plertplaipan, Mr.
Kanongsak Clusintragul and Mr. Nipon Poorpromyod for
their assistance in some of the experimental work.