Preparation and characterization of TiO2-based nanosheets for photocatalytic degradation of acetylsalicylic acid: Influence of calcination temperature

•TiO2-BNSs were synthesized by hydrothermal method on the surface of Ti plates.•Calcination temperature affected the architecture and crystal property of BNSs.•TiO2-BNSs-500 showed high anatase crystallinity and highly ordered structure.•TiO2-BNSs-500 displayed high separation and transfer of the photoinduced electrons.•TiO2-BNSs-500 exhibited excellent photocatalytic efficiency.

TiO2-based nanosheets (BNSs) were synthesized via hydrothermal method and acid-washing procedure, followed by calcinating at different temperatures in air. The resulting TiO2-BNSs were characterized by XRD, SEM, DRS and PL. The photoelectrochemical properties of TiO2-BNSs were measured through transient photocurrent response (TPR), open-circuit potential (OCP) and electrochemical impedance spectroscopy (EIS). The prepared TiO2-BNSs were used to the photocatalytic degradation of acetylsalicylic acid. The results indicated that the samples calcinated at different temperatures exhibited the nanosheets architectures with the lengths in the range of 500–1500 nm and thickness of approximately 30 nm. The crystallinity of the samples enhanced as increasing the calcination temperature from 400 °C to 600 °C. Among the TiO2-BNSs samples, the 500 °C-calcinated nanosheets (TiO2-BNSs-500) exhibited the relatively uniform and regular nanosheet structure. The phase transformation from anatase to rutile phase happened at 500 °C. TiO2-BNSs-500, TiO2-BNSs-550 and TiO2-BNSs-600 possessed the biphase structure of anatase–rutile. And, the visible light absorption, electron–hole pairs separation and transfer efficiency, photocatalytic activities for the degradation of acetylsalicylic acid and OH yield of the samples presented the similar variation tendency which improved as increasing the calcinated temperatures from 400 to 500 °C and then declined at 550 and 600 °C. Accordingly, the degradation rate of acetylsalicylic acid for 120 min reaction was 87.8% when TiO2-BNSs-500 was employed as the photocatalyst. The photocatalytic degradation reaction fitted the pseudo-first-order kinetics and OH was the crucial oxidative species.

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