期刊
NANO RESEARCH
卷 11, 期 1, 页码 126-141出版社
TSINGHUA UNIV PRESS
DOI: 10.1007/s12274-017-1612-5
关键词
Ag; TiO2; 4-nitrophenol; heterojunction; photothermal catalysis
类别
资金
- National Natural Science Foundation of China [21631004, 21601055]
- International Science & Technology Cooperation Program of China [2014DFR41110]
- Fundamental Research Funds for the Central Universities [2572015CB27]
The development of effective catalysts for the catalytic conversion of the harmful nitrophenol (NP) into the useful aminophenol (AP) has received extensive interest. Herein, we report the easy and large-scale synthesis of strongly coupled Ag/TiO2 heterojunctions based on the coordinated action of organic components with a multi-kind metal precursor. The heterojunctions were effective and stable catalysts for the photothermal catalytic reduction of 4-NP to 4-AP. In the synthesis, critic acid, ethylene glycol, AgNO3, and tetrabutyl titanate were dissolved and coordinated in water. Under heating, a precursor gel having a uniform distribution of Ag and Ti was gradually formed. Via calcination in air, the Ti precursor was transformed into TiO2, accompanied by the reduction of Ag+ to Ag nanoparticles. The formation of Ag/TiO2 composites with intimate interface contact benefited from the uniform distribution of different components in the precursor gel. The Ag/TiO2 functioned as an effective catalyst for the reduction of 4-NP, exhibiting higher activity than the many reported Ag-based catalysts. The catalytic reaction over Ag/TiO2 had a small t(0) with good activity and reuse performance. After 10 cycles of reuse, the conversion efficiency exhibited no obvious change. Importantly, the conversion of 4-NP was significantly enhanced under light irradiation provided by a 150-W Xe lamp (the visible light from cutoff have equal function), but ultraviolet light did not promote the conversion. The conversion time was reduced from 620 to 270 s with light irradiation (15 degrees C). The reaction rate under light irradiation (0.014 s(-1)) was approximately three times higher than that in the dark at 15 degrees C (0.0044 s(-1)) and even better than that in the dark at 25 degrees C (0.01 s(-1)). A series of experiments indicated that the light irradiation promoted the conversion of 4-NP because of the localized surface plasmon resonance effect of Ag, which generated hot e(-) and h(+) particles and local heating around the particles via their absorption of the light.
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