Unraveling the Carrier Dynamics and Photocatalytic Pathway in Carbon Dots and Pollutants of Wastewater System

Photocatalysis using polluted water where organic pollutants act as electron and hole transferring agents and carbon dots (C-Dots) act as a photosensitizer is a new game-changing approach for next generation photocatalysis. We demonstrate here an excellent approach for photocatalysis using water-soluble pollutants as a sacrificial electron acceptor (benzoquinone, BQ) and a sacrificial hole acceptor (pyrazine, PYZ), creating a mimic of untreated wastewater. BQ and PYZ are two common pollutants which are found in industrial wastewater. Here, charge separation and recombination processes are investigated to find out the exact mechanism for an efficient homogeneous photocatalysis process with myriad uses of steady state, time-resolved photoluminescence and ultrafast transient absorption spectroscopy. Furthermore, we demonstrate the proof of concept in charge separation using wastewater pollutants which may provide a new cost-efficient approach for improving the efficiency of photocatalysis, where we found that the efficiency of methylene blue and rhodamine B degradation is improved in the presence of pollutants with a photosensitizer (C-Dots). This finding will create a new avenue for the design and development of cost-efficient solar-driven hydrogen production and improvement of photocatalytic activity using untreated wastewater.