Effect of yttrium doping on the crystal structure, optical, and photocatalytic properties.

What is it about?

The hydrothermal technique was utilized to fabricate yttrium doped ZnO nanorods (Y-doped ZnO). Various spectroscopic approaches were used to examine the effect of yttrium doping on the crystal structure, shape, energy bandgap, and photocatalytic performance of ZnO nanorods. The fact that Y-doped ZnO nanocatalysts had the same hexagonal wurtzite crystal structure and nanorod shape as like undoped ZnO, signifying that doped yttrium ions have no effect on the structural as well as morphological features of ZnO nanorods. By doping yttrium into the ZnO sites, the bandgap energy of the ZnO nanorods was significantly altered, and the photodegradation activity was improved. The absorption edge of the Y-doped ZnO nanorods was shifted towards the higher wavelengths and blue shift in bandgap was observed. It has been confirmed that yttrium doping increases the light sensitivity of ZnO in the visible region while providing several active charge transporters on the nanorods surface as well. The photocatalytic activity of Y-doped ZnO nanocatalysts was significantly increased by generated charge carriers. For doping concentrations of 1 %, 3 % and 5 %, the photodegradation activity of Y-doped ZnO nanorods is 71 %, 97 %, and 82 %, respectively, whereas the photodegradation efficiency of pure ZnO nanorods is 22 %. The photodegradation efficiency of ZnO:Y3 was found to be 4.4 times higher than the pristine ZnO nanorods. In addition to the photodegradation, the Y-doped ZnO nanorods are anticipated to offer a valued platform to the widespread applications in the field of photocatalysis like electrochemical water splitting, hydrogen production and supercapacitors.

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Why is it important?

The preparation of nano-sized ZnO material is of huge significance for the primary study as well as the realistic usages. In this way, the different synthesis methods, for instance, sol–gel, hydrothermal, spray pyrolysis, chemical precipitation and thermal decomposition have been taken up for the preparation of nano-sized ZnO with uniform morphology. Out of these techniques, a hydrothermal technique is one of the magnificent procedures for the synthesis of nano-sized ZnO rods since it is simple to deal with, and permits us to alter the structure of the nanoparticles by altering the dopant concentration, rate, temperature as well as span of hydrolysis reactions [8]. Moreover, ZnO nano-sized materials have recently been used for purifying air and water because they have stronger photocatalytic properties. For the successive decolourization of organic dye components in water, the catalyst may have a better surface area and active sites in the surface. It describes that there is a need for modification of the catalyst morphology by the development of nanostructures over crystallographically oriented substrate molecules. In this regard, ZnO is invaluable as a result of its characteristic properties, for example, wide scope for easy modification of the morphology of substrate surface, easy preparation of nanocrystalline ZnO at low temperatures and regenerative ability at a lower temperature. These highlights make the photoactive nano-ZnO [9].

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