Enhanced Solar Photothermal Catalysis over Solution Plasma Activated TiO2

• Published in: Advanced science Vol. 7; no. 16; pp. 2000204 - n/a
• Main Authors: Yu, Fei, Wang, Changhua, Li, Yingying, Ma, He, Wang, Rui, Liu, Yichun, Suzuki, Norihiro, Terashima, Chiaki, Ohtani, Bunsho, Ochiai, Tsuyoshi, Fujishima, Akira, Zhang, Xintong
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley and Sons Inc 01.08.2020; Wiley
• Subjects: Communication; Communications; oxygen vacancies; photothermal catalysis; solar energy; solution plasma
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202000204

Colored wide‐bandgap semiconductor oxides with abundant mid‐gap states have long been regarded as promising visible light responsive photocatalysts. However, their catalytic activities are hampered by charge recombination at deep level defects, which constitutes the critical challenge to practical applications of these oxide photocatalysts. To address the challenge, a strategy is proposed here that includes creating shallow‐level defects above the deep‐level defects and thermal activating the migration of trapped electrons out of the deep‐level defects via these shallow defects. A simple and scalable solution plasma processing (SPP) technique is developed to process the presynthesized yellow TiO2 with numerous oxygen vacancies (Ov), which incorporates hydrogen dopants into the TiO2 lattice and creates shallow‐level defects above deep level of Ov, meanwhile retaining the original visible absorption of the colored TiO2. At elevated temperature, the SPP‐treated TiO2 exhibits a 300 times higher conversion rate for CO2 reduction under solar light irradiation and a 7.5 times higher removal rate of acetaldehyde under UV light irradiation, suggesting the effectiveness of the proposed strategy to enhance the photoactivity of colored wide‐bandgap oxides for energy and environmental applications. Solution plasma brings H doping into oxygen vacancy type TiO2. The H dopant bridges the gap between the oxygen vacancy (Ov) and conduction band (CB), resulting in photothermal extraction of trapped electrons at the Ov to CB. The solution plasma strategy endows a 300 times higher conversion rate for CO2 reduction under solar light at 393 K than that at 298 K.