In this experiment, the goal is to analyze the effectiveness of using graphene quantum dots to assist titanium dioxide photocatalysis when using light that has a wavelength longer than 407 nm. 407 nm light has the correct amount of energy to excite an electron in the valence shell of titanium dioxide to the conduction band, leaving behind a hole that allows hydroxyl radicals to form and therefore allowing photocatalysis to occur. Light with a wavelength longer than 407 nm would not have enough energy to excite an electron from the valence band to the conduction band.  However, graphene quantum dots have the ability to both up- and down-convert light meaning that when they are excited with any light in the visible spectrum, the emitted light is at 407nm.  For example, excitation light at 300 nm gets down-converted to emit 407 nm, and 500 nm light gets up-converted to emit 407 nm. Because of this, graphene quantum dots when used in conjunction with titanium dioxide for photocatalysis, allows for longer, lower energy wavelengths to be used.  The longer wavelength light is converted to the correct wavelength to excite titanium dioxide which then leaves behind holes, creates hydroxyl radicals, and causes photocatalysis to occur.  To do this, graphene quantum dots are created and analyzed using a fluorimeter to determine at what wavelengths, longer than 407 nm, they up-convert light. Finally, the optimum wavelengths are used on a graphene quantum dot and titanium dioxide complex to determine the effectiveness of the graphene quantum dots in assisting photocatalysis at wavelengths longer than 407 nm.  This poster will present the findings of this study.

Use of graphene quantum dots to assist in photocatalysis

251st National Meeting (2016)

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