Oomman K Varghese
University of Houston, USA
Title: Advanced materials for solar photoelectrochemical fuel generation
Biography
Biography: Oomman K Varghese
Abstract
Fuel generation using solar energy has been widely investigated as a potential pathway for sustainable development in the energy sector. Various technologies, normal and hybrid, have emerged in recent years to generate fuels from sources such as water and carbon dioxide utilizing the ultraviolet/visible or thermal (or both) components of the solar spectrum. Solar photoelectrochemical fuel generation is one such technology that utilizes the photocatalytic properties of semiconducting materials to convert energy in the ultraviolet/visible part of the solar spectrum to fuels. The process does not require elevated temperature or pressure conditions. The sunlight to fuel conversion efficiency is, however, not yet high enough to apply the technology on a commercial scale. The primary limitation is in the inability of the photocatalysts to absorb visible light photons or transport the photo-generated charge carriers to the surface for redox reactions. Wide band gap photocatalysts such as titanium dioxide transport charge carriers relatively better than narrow band gap semiconductors such as iron oxide; however, wide band gap materials utilize only the ultraviolet photons. We recently introduced a strategy that consists of joining a wide band gap and a narrow band gap nanoarchitecture to form a heterostructure photoelectrode. Such electrodes exhibited promising characteristics for broad-spectrum light utilization. These results along with the current state of the technology will be discussed in this presentation.