Dr. Abdou Lachgar | Wake Forest University
Event Date:
April 14, 2016 – 3:30 PM
Location:
Burson 115
Event Date:
April 14, 2016 – 3:30 PM
Location:
Burson 115
Ph.D Nanoscale Science Seminar Series | Spring 2016
Dr. Abdou Lachgar
Wake Forest University
Dept. of Chemistry, and Center for Energy, Environment and Sustainability
“Semiconductor heterojunctions for Enhanced Photocatalytic Activity”
Abstract:
Semiconductor-based photocatalysis has received tremendous attention in the last few decades because of its potential for solving current energy and environmental problems. In a semiconductor photocatalytic system, photo–induced electron-hole pairs are produced when a photocatalyst is irradiated by light with frequencies larger than that of its band gap (h? ? Eg). The photo-generated charge carriers can either recombine, or migrate to the surface of the semiconductor, where they can be involved in electrochemical processes. High recombination rate of charge carriers and limited efficiency under visible light irradiation are two limiting factors in the development of efficient semiconductor-based photocatalysts. To overcome these drawbacks, a number of chemical and design strategies have been developed. Among these strategies, the design and formation of semiconductor heterojunctions using two or more semiconductors is a promising approach. Recently studied examples of these semiconductor heterojunctions will be presented to demonstrate that well designed heterojunctions can extend light absorption range and enhance the life time of photogenerated charge-carriers resulting in enhanced photocatalytic activity compared to their individual components. The plausible mechanism (Figure 1) for the enhanced photocatalytic activity for the heterostructured composites is proposed based on observed activity and band positions calculations.
Description of Research
The ability to optimize various physical and chemical properties of materials, and to develop entirely new materials is at the heart of my research interest. The aim is to design, synthesize and characterized multifunctional materials which are materials that can be used for multiple functions (catalysis, conductivity, magnetism, luminescence, etc..) microwave, etc.). The approach used to reach our goal is the molecular building block approach in which specific molecular species are first synthesized then put together in a rational way to give specific structures with specific chemical and physical properties. The materials targeted have potential applications in Hydrogen storage, CO2 sequestration, environmental remediation, and Biodiesel production. Three main projects are currently investigated:
- Cluster-based Metal Organic Materials (CMOMs)
- Hybrid organic-inorganic phosphates and phosphonates (HOIPs)
- Natural products based catalysts for Biodiesel Production (NPCs)