Abstract
Herein, a sustainable and scalable planetary ball milling technique was applied for grinding and exfoliation of graphitic carbon nitride (g-C 3 N 4 ) to enhance its photocatalytic activity. In this study, the effect of the rotational speed during planetary ball milling on the exfoliation of bulk g-C 3 N 4 and its photocatalytic performance was systematically investigated. The effectiveness of the ball milling technique was evaluated in comparison to the well-established ultrasonic exfoliation method. The efficiency of exfoliating g-C 3 N 4 samples was evaluated based on their photocatalytic activity, specifically through the photocatalytic decomposition of the organic dye Orange II under visible light irradiation. As a result, the photocatalytic activity of g-C 3 N 4 exfoliated in a ball mill at 800 rpm for 10 min was found to be higher than that of g-C 3 N 4 exfoliated by ultrasonic method and two times higher than that of bulk g-C 3 N 4 . The ball mill-exfoliated g-C 3 N 4 demonstrated a highly efficient photocatalytic hydrogen evolution performance, with hydrogen evolution rate (HER) of 4117.86 µmolh −1 g −1 , which is more than seven times higher than that of the bulk g-C 3 N 4 material. The obtained results confirm that the mechanical activation technique warrants more attention, as all samples processed using this method delivered higher photocatalytic performance compared to those processed by other methods.