Prof. Xiaohong Yang, Associate Professor, Northeastern University, China.
Speech Title: Synthesis of Metal oxide@TiO2 core-shell nanostructures for enhanced visible light photocatalytic performance
Abstract: Our work developed a series of core-shell structures by coating TiO2 onto the surface of different metal oxides, verifying the proposed hypothesis that choosing the metal oxides, with lower band gap than that of TiO2, as well as higher electronic affinity compared with the work function of TiO2, as core, may lead to the visible light response of the core-shell structure and highly inhibit the electron-hole recombination, finally increase the photo catalytic efficiency. Through three years research work, we have successfully developed a range of TiO2 coated metal oxides core-shell structure, and got some important results, as discussed below:
1.Spherical TiO2 precursors could be formed by adding the mixture of tetrabutyl titanate and ethylene glycol into acetone through sol-gel reaction at room temperature. When heterogeneous particles exiting in acetone, TiO2 precursors colloids could deposit on the surface of particles first, forming a heterogeneous particle@TiO2 core-shell structure.
2.Crystallization of TiO2 occurs with hydrothermal treatment at 100℃, thus, we successfully developed a simple and general strategy to synthesize TiO2 based core-shell structure with various particles as the core. By this means, a series of metal oxides@TiO2 core-shell structures with different morphology were developed, such as Fe2O3@TiO2, V2O5@TiO2, In2O3@TiO2, WO3@TiO2 core-shell structures, and the thickness of TiO2 coating could be controlled by adjusting the amount of TiO2 precursors.
Aiming at how to choose a suitable "core" in core-shell structure as a high-efficiency photocatalytic materials, this project verified our proposed statement through experiment comparison and DFT calculation, that is, choosing the metal oxides with narrower band gap compared with titanium dioxide band gap, with greater electron affinity than the work function of titanium dioxide, can effectively improve the light absorption capacity and electron transfer efficiency of the titanium dioxide-based photocatalyst, ultimately greatly improve the photocatalytic performance of titanium dioxide. The optimized visible light catalytic activity of the core-shell heterostructure is usually2-5 times higher than that of pure titanium dioxide.
Dr. Nevenka R. Elezovic
Dr. Muhammad Sultan, Bahauddin Zakariya University, Pakistan.
Speech Title: Energy-efficient humidity pump systems for agricultural applications
Abstract: For any nation, primary sources of energy consumption are involved in: heating, cooling, humidification, dehumidification, ventilation and/or air-conditioning (HVAC), which may be required for various applications. Currently, Pakistan is facing extreme energy shortage, therefore, low-cost and energy-efficient HVAC systems are principally required. As the Pakistan is an agriculture dependent country, therefore, low-cost HVAC systems are required not only for humans’ thermal comfort but also for various agriculture based applications e.g. greenhouse air-conditioning, agricultural products’ (fruits and vegetables) storage, and animals’ (livestock) air-conditioning etc. In this regard, various innovative cooling and air-conditioning technologies have been introduced worldwide. Consequently, in this keynote speech, evaporative cooling and adsorption cooling based HVAC technologies are explored. These technologies are environmentally safe and can be simply operated by water or low-grade waste heat. The low-grade waste heat can be supplied economically by many ways e.g. solar thermal energy, natural coal, bio-gas and/or bio-mass etc. From the prospective of evaporative cooling, the speech focuses on Maisotsenko cycle (M-cycle) based evaporative cooling conception in comparison with conventional direct and indirect evaporative cooling. While adsorption cooling and desiccant air-conditioning systems are focused from the prospective of thermally driven systems. Importance of selection of refrigerant and adsorbent/desiccant is also highlighted. Based on geographic and climatic conditions of Pakistan, role of temporal and spatial variation for the development of sustainable HVAC system is addressed.