Earth Abundant Metals as Cost Effective Alternatives in Photocatalytic Applications: A Review

Abstract

In a quest for a cleaner planet and to have alternative forms of energy generation apart from the fossil-based power supply, fuel cell technology has emerged as an alternative energy source for usage across all economic sectors. The application of this age-old technology is found in alkaline (AFC), molten carbonate (MCFC), phosphoric acid (PAFC), polymer electrolyte membrane (PEMFC) and solid oxide (SOFC) fuel cells. These fuel cells are named based on the type of electrolyte employed in their applications and the fuel of choice for energy generation is hydrogen. This fuel can be used in its pure form or extracted from other sources such as methanol, water and syngas. Ammonia in its liquefied and gaseous forms may be used as a non-carbonaceous fuel for the hydrogen source in some of these fuel cell technologies due to its safety, lower price, ease of storage and transportation. In this review, all the fuel cells will be investigated in their capability of using ammonia as a direct fuel. The role of earth abundant metal catalysts in comparison to TiO2 was evaluated in terms of molecular orbital theory and in the decomposition of organic compounds and other material into nitrogen and hydrogen products under the visible light radiation. The p-orbital participation in earth abundant metals or metal oxides doping, emerged as a strong contribution to bandgap attenuation.

Effects of thermal treatment on the complex structure of luminescence emission of Li-doped ZnO screen-printed films

“…Earth-abundant materials suitable for several modern applications have attracted great interest due to the development of eco-friendly and low-cost basic compounds for electronic devices. The most promising earth-abundant materials currently considered for solar energy production and optoelectronic applications include (but will not be limited to) sulfides/selenides, nitrides, phosphides, and oxides [1][2][3][4][5]. Optoelectronics needs the development of earthabundant luminescent materials instead of rare-earth-activated luminophores that are currently used in many devices because the high-technology and environmental applications of the RE elements have grown dramatically in diversity and importance over the last 4 decades [6][7][8].…”