S. Kulkarni
Texas A&M University- Kingsville, USA
Title: Review of techniques used in the synthesis of next-generation photo catalysts
Biography
Biography: S. Kulkarni
Abstract
The rapidly increasing demand for sustainable energy source coupled with the need for a green energy has currently called for a heightened global attention, and “Hydrogen Economy” has been considered as a potential solution to this problem. There are several sustainable processes of hydrogen production that have and are being developed. Hydrogen production is currently being carried out by steam reforming of natural gas on an industrial-scale. However, steam methane reforming (SMR) method is again carbon and energy intensive and leads to addition of CO2 to the atmosphere. Splitting of water using renewable energy sources is one of the cleanest techniques of hydrogen production that does not require any additional hydrogen purification. The main challenge in this route being harvesting of renewable energy sources for hydrogen generation in such a way that the energy costs would compare with that of fossil fuels. Direct photolysis of water using light as the source of energy has great potential to overcome the problems associated with hydrogen economy [3]. In this process, a stable molecule of water is split into hydrogen and oxygen using light as the source of energy. A total of 237 KJ/mol of energy is required for the reaction to take place. Apart from the thermodynamic limitations, the kinetic barriers also play a significant role in photolysis. In order to overcome these barriers photocatalysts are required, which reduce the activation energy needed to carry out the chemistry. Some of the nano-photocatalysts used today are metal oxides such as TiO2 and ZrO2, metal sulfides, metal phosphides, sub-nm Au clusters etc. Although several nano-photocatalysts have been developed, more research is required in the design of a robust photocatalyst with high photonic efficiencies and long-term stability. Photocatalysts available today can be activated only by the UV spectrum of the solar irradiation, although it is desired that these catalysts absorb from the wide solar spectra. Recently, cobalt oxide nano-particles have been demonstrated to efficiently split water under visible light irradiation without the use of sacrificial reagents or co-catalysts [4]. This paper reviews the various synthesis techniques available today to design and synthesize various nano-photocatalysts with an emphasis on CoO nano-particle synthesis. This article serves as a prelude to the work on the activation of carbon dioxide at extreme pressures to methane using hydrogen produced by photolysis of water.