Synthesis, characterization and investigation of catalytic activities of hexagonal boron nitride incorporated perovskite catalysts

In the present doctoral study; the photocatalytic activities of two-dimensional hexagonal boron nitride (h-BN) and zero-dimensional boron nitride quantum dot (BNQDs) forms of boron nitride were examined in order to gain them in the field of photocatalysis. In the first part; BiFeO3 (BFO) and MnFeO3 (MFO) perovskite catalysts were doped with h-BN by impregnation to improve their optical properties and catalytic activities. The characterization of the catalysts was investigated in detail by SEM-EDS, TEM, XRD, XPS, FTIR, PL, UV−vis DRS, EIS and BET analyses. In FTIR and XPS results; the peaks of pure h-BN and perovskite structures were observed, indicating that boron nitride was successfully added to the perovskite structure. In the optical analyses; the light absorption capacity of the catalysts increased significantly and the recombination rate decreased after incorporation with h-BN. In photocatalytic activity studies, after addition of h-BN, tetracycline (TC) removal performances of pure BFO (65.4%) and MFO (44.2%) catalysts increased to 80.1% and 75.8%, respectively. BFO/h-BN and MFO/h-BN catalysts showed high catalytic performance for pharmaceutical production plant wastewater effluent containing ibuprofen. In the second part; it was aimed to improve the performances of BFO and MFO catalysts with incorporation of BNQDs. It was observed in the TEM images that spherical quantum dots were successfully added on the perovskite surfaces. The charge transfer capacities of perovskite photocatalysts were effectively improved with the addition of BNQDs. After BNQDs doping, the photocatalytic performances of pure BFO and MFO catalysts increased to 80% and 70%, respectively, which was attributed to the hole extraction ability of BNQDs. In the last part, the BFO/BNQDs/1 catalyst which showed maximum performance during the thesis study was coated on the polyester fiber filter surface and its practical applicability was investigated. The degradation by catalytic filter was achieved by peroxymonosulfate activation as an electron acceptor. Firstly, the effect of different coating ratios on the performance of the filter was investigated. After that, photocatalysis/PMS mechanism was explained by radical scavenging experiments. With the cycle experiments, the catalytic filter provided effective performance until the fifth use and it was seen by the characterization tests that the catalysts were stable on the filter surface. TC degradation in a continuous flow system with catalytic filters was investigated with the parameters of flow rate, bed height and pollutant concentration. The catalytic filters provided effective catalytic performance for 7 hours. As a result, the physicochemical, optical and photoelectrochemical properties of perovskite catalysts were succesffuly improved by different forms of boron nitride and the catalytic activities against various pollutants were greatly increased. This study demonstrated that boron nitride has a promising potential in the field of photocatalysis.