Physical and Analytical Chemistry Seminar
Lecturer: Dr. Shaik Firdoz
Location: Faculty Seminar Room
The solar-driven semiconductor based photocatalytic splitting of water into hydrogen and oxygen, and CO2 reduction to solar fuels is potential source of clean and renewable fuels. However, even after four decades of global research, systems that are sufficiently stable and efficient for practical use have not yet been realized. In this seminar presentation, I will discuss on the rational design and fabrication of advanced semiconductor based photocatalytic nanohybrids for efficient solar-fuel conversion systems.
Solar-fuel conversion reactions often rely on multiple photo-induced charge carriers and have undesirable pathways which limit their efficiency. Our novel strategy based on fusion of plasmonic nanostructures with photocatalytic nanohybrids employs plasmons for generation of multi-excitonic state in semiconductor photocatalyst. A plasmonic antenna, comprised of Au nanoprisms, was employed to accomplish feasible levels of multiple carrier excitations in semiconductor nanocrystal-based photocatalytic systems (CdSe@CdS core-shell quantum dots and CdSe@CdS seeded nanorods). The antenna’s near-field amplifies the otherwise inherently weak bi-exciton generation in the semiconductor. This work relies uniquely on a non-linear enhancement that has potential for large amplification of photocatalytic activity in the presence of a plasmonic near-field.
Plasmonic g-C3N4 nanohybrids systems such as Au@g-C3N4 core-shell and Au@g-C3N4 yolk-shell are also developed. Graphitic carbon nitride (g-C3N4) has appealing electronic band structure and high physicochemical stability. These plasmonic nanohybrids exhibit plasmon enhanced photocurrent generation of nearly 4-fold higher compared with g-C3N4 hollow nanospheres. In addition, I will also discuss on the correlation between the photocatalytic activity of amino-modified g-C3N4 nanospheres of different sizes for hydrogen production based on the transient changes occurring on nano-time scale range with pulsed photo-excitation on the FT-IR spectrum.
Finally, I will discuss on the design and fabrication of advanced novel quaternary nanohybrid photocatalyst system consist of g-C3N4 hollow nanospheres integrated with Ni/Pt tipped CdSe-CdS seeded nanorods as efficient photocatalyst system for overall water splitting reactions using visible light. We also investigated on the effect of different types of electron or hole transfer ligands on the surface of g-C3N4 hollow nanospheres towards its photocatalytic activity for overall water splitting reactions. The seminar will be concluded on the prospective design and usage of different types of advanced novel photocatalytic nanohybrids for energy and environmental applications.