Effect of MCAA Synthesis and Calcination Temperature on Heterojunction Formation and Photocatalytic Activity of Biphasic TiO2 (B/A)

Effect of MCAA Synthesis and Calcination Temperature on Heterojunction Formation and Photocatalytic Activity of Biphasic TiO2 (B/A)

Článek WoS

This study investigates the impact of calcination temperature and the use of monochloroacetic acid (MCAA) as a complexing agent during the synthesis of TiO2 heterojunctions on the photocatalytic performance of TiO2 containing a heterojunction of anatase (A) and brookite (B). The TiO2 samples were dried at 100 °C and subjected to calcination in the temperature range of 200–500 °C. As the calcination temperature increased, changes in chemical composition, phase composition, specific surface area, pore size distribution, and band gap energy were observed, influencing the photocatalytic behavior during Acid Orange (AO7) photodegradation. With increasing calcination temperature, the anatase content slightly increased to 81.8 wt.%, while the brookite content decreased. Additionally, the anatase crystallite size increased from 5 to 7 nm, and the brookite crystallite size increased from 8 to 11 nm. These phase changes were characterized by a slight decrease in the brookite/anatase (B/A) molar ratio from 0.27 to 0.22. Concurrently, the specific surface area of TiO2 samples decreased from 180 to 70 m2 g−1, accompanied by alterations in the pore size distribution. The decrease in photocatalytic activity was evident, as the apparent rate constant kapp of AO7 photodegradation declined from 2.1 × 10–3 min−1 (100 °C) to 0.7 × 10–3 min−1 (500 °C). This reduction was attributed to the partial destruction of anatase/brookite heterojunctions on the photocatalyst surface, which underwent changes in size and surface structure due to sintering. Moreover, the presence of Ti3+, Ti4+, Ti–O, and Ti–OH hydroxyl groups played a significant role in the degradation process. Overall, this investigation sheds light on the crucial role of calcination temperature in modulating the photocatalytic properties of TiO2 heterojunctions and highlights the importance of heterojunction in enhancing photocatalytic activity.

This study investigates the impact of calcination temperature and the use of monochloroacetic acid (MCAA) as a complexing agent during the synthesis of TiO2 heterojunctions on the photocatalytic performance of TiO2 containing a heterojunction of anatase (A) and brookite (B). The TiO2 samples were dried at 100 °C and subjected to calcination in the temperature range of 200–500 °C. As the calcination temperature increased, changes in chemical composition, phase composition, specific surface area, pore size distribution, and band gap energy were observed, influencing the photocatalytic behavior during Acid Orange (AO7) photodegradation. With increasing calcination temperature, the anatase content slightly increased to 81.8 wt.%, while the brookite content decreased. Additionally, the anatase crystallite size increased from 5 to 7 nm, and the brookite crystallite size increased from 8 to 11 nm. These phase changes were characterized by a slight decrease in the brookite/anatase (B/A) molar ratio from 0.27 to 0.22. Concurrently, the specific surface area of TiO2 samples decreased from 180 to 70 m2 g−1, accompanied by alterations in the pore size distribution. The decrease in photocatalytic activity was evident, as the apparent rate constant kapp of AO7 photodegradation declined from 2.1 × 10–3 min−1 (100 °C) to 0.7 × 10–3 min−1 (500 °C). This reduction was attributed to the partial destruction of anatase/brookite heterojunctions on the photocatalyst surface, which underwent changes in size and surface structure due to sintering. Moreover, the presence of Ti3+, Ti4+, Ti–O, and Ti–OH hydroxyl groups played a significant role in the degradation process. Overall, this investigation sheds light on the crucial role of calcination temperature in modulating the photocatalytic properties of TiO2 heterojunctions and highlights the importance of heterojunction in enhancing photocatalytic activity.

anatase, brookite, heterophase junction, calcination temperature, AO7 photodegradation.

anatase, brookite, heterophase junction, calcination temperature, AO7 photodegradation.

TINOCO NAVARRO, L.; CIHLÁŘ, J.; MICHALIČKA, J.; KAŠTYL, J.; ČÁSTKOVÁ, K.

2024

24.10.2023

SpringerNature

1011-372X

CATALYSIS LETTERS

153

11

Spojené státy americké

21

21

https://link.springer.com/article/10.1007/s10562-023-04489-7