Research on the preparation of tubular g-C3N4/CQDs composites and its photocatalytic degradation towards methylene blue
Carbon quantum dots(CQDs)was synthesized using hemp leaves and ammonium fluoride as feedstocks through microwave alcohol solvothermal method.Then,the above CQDs was loaded onto the complex precursor of melamine and cyanic acid by consecutively stirring and spinning evaporation.After drying,g-C3N4/CQDs composite photocatalyst was prepared by one-step calcination methodology.After analyses on its structure,composition and morphology,the photocatalytic property was assessed by degrading the methylene blue(MB).The results show that g-C3N4/CQDs presents a tubular morphology and has a higher visible light response ability.Compared with the blank g-C3N4,the g-C3N4/CQDs complex showed a higher photocatalytic degradation ability with a degradation efficiency toward MB up to 80.8%under UV-vis light irradiation with xenon lamp for 120 min,while the blank g-C3N4 was only 31.9%,confirming an increase of 1.53 times.The mechanism analysis elucidates that the improvement of photocatalytic performance is mainly attributed to the improved morphology and structure of the catalyst,the improved visible light response together with the accelerated photo-generated charges migration rate of CQDs.