Effects of nonequilibrium atmospheric-pressure O2 plasma-assisted annealing on anatase TiO2 nanoparticles
Effects of nonequilibrium atmospheric-pressure O2 plasma-assisted annealing on anatase TiO2 nanoparticles
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DOI：
10.1016/j.apsusc.2020.146684
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发表时间：
2020-10
影响因子：
6.7
通讯作者：
Retsuo Kawakami;Yuki Yoshitani;A. Shirai;S. Yanagiya;Hirofumi Koide;Yuki Mimoto;Kosuke Kajikawa;M. Niibe;Y. Nakano;Chisato Azuma;T. Mukai
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文献类型：
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作者：
Retsuo Kawakami;Yuki Yoshitani;A. Shirai;S. Yanagiya;Hirofumi Koide;Yuki Mimoto;Kosuke Kajikawa;M. Niibe;Y. Nakano;Chisato Azuma;T. Mukai
固定在玻璃基板上的锐钛矿型 TiO2 纳米颗粒 (NPs) 在非平衡大气压 O2 等离子体的辅助下进行退火。与电炉退火相比，等离子体辅助退火大大增强了光分解和光杀菌活性。等离子体辅助退火降低了TiO2NP团聚体的尺寸，增加了光吸收、光致电导率、桥接和端氧基的数量以及(1 1 2)/(1 0 1)平面强度比，导致晶格氧缺陷，形成部分富钛表面部分。增强的光杀菌活性源自桥接和末端氧基团。由于以下三个因素，光生载流子浓度增加会导致光分解增强。第一个是团聚体尺寸减小和 (1 1 2) 平面生长或出现而增加的光吸收，这会散射更多的入射光子。第二个是桥接和末端氧基团促进光生载流子的电荷分离，这些氧基团源自等离子体的氧离子撞击产生的氧空位。第三个是等离激元激发的电子从部分富钛部分到 TiO2 的电荷转移。增强的光分解也将由光生载流子从桥接和末端氧基团产生的更多活性氧物质引起。
Anatase TiO2nanoparticles (NPs) immobilized on glass substrates were annealed with the assistance of nonequilibrium atmospheric-pressure O2plasma. The plasma-assisted annealing greatly enhanced the photodecomposition and photobactericidal activity as compared with electric-furnace annealing. The plasma-assisted annealing reduced the TiO2NP agglomerate size and increased the optical absorption, the photoinduced electrical conductivity, the amounts of bridging and terminal oxygen groups, and the (1 1 2)/(1 0 1) plane intensity ratio, causing the lattice oxygen deficiency that formed partially Ti-rich surface portions. The enhanced photobactericidal activity would arise from the bridging and terminal oxygen groups. The enhanced photodecomposition would arise from the increased concentration of photogenerated carriers due to the following three factors. The first is the optical absorption increased by the agglomerate size reduction and the (1 1 2) plane growth or appearance, which exert scattering more incident photons. The second is the charge separation of photogenerated carriers facilitated by the bridging and terminal oxygen groups, which originate from oxygen vacancies via oxygen ion impact from the plasma. The third is the charge transfer of plasmon-excited electrons from the partially Ti-rich portions to TiO2. The enhanced photodecomposition would also arise from more reactive oxygen species generated from the bridging and terminal oxygen groups by the photogenerated carriers.