Metal and Carbon Quantum Dot Photocatalysts for Water Purification

Abstract

Carbon quantum dots are zero-dimensional carbon nanomaterials having a size of less than 10 nm with sp2-/sp3-hybridized carbon atom containing a variety of functional groups at basal plane and periphery. Carbon quantum dots are a new class of carbonaceous material which are recently developed and attracted appreciable importance due to their superlative properties and significant applications in different fields. By virtue of their unique optical, electronic, and efficient light harvesting, tunable photoluminescence, and up-conversion property, carbon quantum dots displayed huge applications in bio-sensing, bio-imaging, drug delivery, photocatalysis, photovoltaics and optoelectronics. Today, contamination of water is one of the biggest and most alarming problems that demands an immediate solution, and non-availability of economical method for water treatment makes it more significant. The potential pollutants of water pollution are heavy metal ions, sewage, pesticide, pharmaceutical waste, and industrial waste. The most abundant carbon as photocatalytic nanomaterial could be a better choice among previously reported conventional photocatalyst and quantum dots.The book chapter aims to demonstrate top-down method and bottom-up method for the fabrication of carbon quantum dots. Further, the basic mechanism of photocatalysis, disadvantages of conventional quantum dots, classification of carbon quantum dots, and the concept behind up-conversion phenomena were also reviewed. The photocatalytic degradation and antimicrobial application of carbon quantum dot-based photocatalyst were also explored. Lastly, conclusion and future perspective were considered and speculated. The design of photocatalytic system with high photo-efficiency is still challenging, and the area remains open to carry out future research.