Enhancing the photocatalytic activity for pollutant degradation and H2 evolution by modifying ZrO2 with nanoclusters of BiVO3, Ag3PO4, SrTiO3 and WO3: A first-principles study

9^th World Congress on Materials Science and Engineering

June 12-14, 2017 Rome, Italy

Francis Opoku, Krishna Kuben Govender, Cornelia Gertina Catharina Elizabeth van Sittert and Penny Poomani Govender

University of Johannesburg, South Africa
Center for High Performance Computing, South Africa
North-West University, South Africa

Scientific Tracks Abstracts: J Material Sci Eng

Abstract :

Environmental pollution and energy exhaustion has received much interest both in scientific and industrial research fields. For this reason, tremendous efforts are made to design novel environmentally friendly non-polluting and sustainable energy storage photocatalysts for efficient solar energy harvesting and conversion. Semiconductor-based photocatalysis has received increasing attention in energy storage and environmental remediation process due to the abundantly solar energy. For this purpose, several heterostructures using BiVO4, Ag3PO4, SrTiO3 and WO3 monolayers coupled with ZrO2 nano-cluster are designed to examine their potential applications in energy storage and degradation of pollutants using density functional theory calculations for the first time. Moreover, the underlying mechanism, band edge positions, optical and electronic properties of the ZrO2-basedheterostructures are evaluated. The results displayed that the calculated band gap of the heterostructures is reduced compared to the pure ZrO2, which favors redshift absorption. A type-I band alignment was attained for the BiVO4/ZrO2, Ag3PO4/ZrO2 and WO3/ZrO2 heterostructures. More importantly, the type-II staggered band alignment formed in the SrTiO3/ZrO2 heterostructure restrained the charge recombination rate of the photoinduced carrier charges, as well as enhancing the photocatalytic activity. Our results display efficient charge separation and visible light response of the BiVO4/ZrO2, Ag3PO4/ZrO2, WO3/ZrO2 and SrTiO3/ZrO2 heterostructures. In particular, suitable band alignment of SrTiO3/ZrO2 with enough driving forces for charge carrier transfer show overall water splitting and degradation of pollutant in which SrTiO3 acted as the charge separation center. Thus, the SrTiO3/ZrO2 heterostructure emerges as a new type of ZrO2-based photocatalyst for efficient solar energy applications. Furthermore, h+, HO� and O2�� radicals played a major role in the photocatalysis process. Finally, possible charge separation and photocatalytic mechanisms of BiVO4/ZrO2, Ag3PO4/ ZrO2, WO3/ZrO2 and SrTiO3/ZrO2 heterostructures are proposed.

Biography :

Francis Opoku received his BSc in Chemistry (2010) and MPhil in Inorganic Chemistry (2014) from the Kwame Nkrumah University of Science and Technology, Ghana. He is now pursuing PhD degree in Chemistry under the supervision of Dr. Penny Poomani Govender, Dr. Krishna Kuben Govender and Dr. Cornelia Gertina Catharina Elizabeth van Sittert in the Department of Applied Chemistry, University of Johannesburg, South Africa. His research interests include the design of efficient semiconductor-based photocatalyst materials and their applications in water splitting as well as degradation of pollutants in wastewater/water resources.

Email: ofrancis2010@gmail.com