TiO2 decorated hydrogel hollow microspheres and their photocatalytic property

Abstract

This paper presents a novel, facile method for fabricating pH-responsive inorganic/organic composite microspheres with hollow structures in the absence of a step for the removal of the core. Using polyelectrolyte hollow microspheres without a need for further calcination and chemical etching, minimally cross-linked poly(methacrylic acid/ethylene glycol dimethacrylate/3-(trimethoxysilyl) propylmethacrylate) [poly(MAA/EGDMA/TMSPM), pMET] microspheres were prepared by a distillation-precipitation method. Once the pMET microspheres disperse in 2-propanol, the hollow structure is clearly observed and can be maintained more rigidly in a dry state after amorphous TiO2 (a-TiO2) is incorporated into the shell of a microsphere by a sol-gel method. The a-TiO2-incorporated pH-responsive pMET composite (pMET/a-TiO2) hollow microspheres were tested as a photocatalyst in acidic and neutral conditions. The photocatalytic performance of the hollow pMET/a-TiO2 composite microcapsules under neutral condition was better than under acidic condition due to their large active surface and strong adsorption ability against methylene blue (MB).|본 연구에서는 저가교도의poly(MAA/EGDMA/TMSPM) (pMET) 하이드로겔 마이크로입자를 이용하여 추후 Calcination이나 Etching과 같은 코어를 제거하는 공정이 필요없는 중공구조의 poly(MAA/EGDMA/TMSPM)/amorphous TiO2 입자 (pMET/a-TiO2)를 손쉽게 제조했다. 저가교도의 pMET 입자는 2-propanol에 분산 되었을 때 더 명확한 중공구조가 관찰되었으며, Amorphous TiO2 (a-TiO2)입자는 pMET 입자의 쉘 부분에 졸-겔법으로 도입되었다. 제조된 입자의 모폴로지 및 pH에 따른 입자의 거동은 SEM, FIB-SEM, TEM, HR-TEM, OM, CLSM을 통하여 조사하였다. 중공구조의 pMET/a-TiO2 입자는 광촉매로써 산성 조건과 중성 조건에서 광특성 테스트를 실시하였으며, 비어있는 내부와 외부의 비표면적과 Methylene blue (MB)의 흡착도에 따라 다른 성능을 나타내었다. pH에 따라 반응하는 중공구조의 pMET/a-TiO2 입자는 산성 조건보다 중성 조건에서 더 좋은 광특성을 보였다. 이 광특성은 UV-vis spectrometer를 사용하여 조사하였다.; This paper presents a novel, facile method for fabricating pH-responsive inorganic/organic composite microspheres with hollow structures in the absence of a step for the removal of the core. Using polyelectrolyte hollow microspheres without a need for further calcination and chemical etching, minimally cross-linked poly(methacrylic acid/ethylene glycol dimethacrylate/3-(trimethoxysilyl) propylmethacrylate) [poly(MAA/EGDMA/TMSPM), pMET] microspheres were prepared by a distillation-precipitation method. Once the pMET microspheres disperse in 2-propanol, the hollow structure is clearly observed and can be maintained more rigidly in a dry state after amorphous TiO2 (a-TiO2) is incorporated into the shell of a microsphere by a sol-gel method. The a-TiO2-incorporated pH-responsive pMET composite (pMET/a-TiO2) hollow microspheres were tested as a photocatalyst in acidic and neutral conditions. The photocatalytic performance of the hollow pMET/a-TiO2 composite microcapsules under neutral condition was better than under acidic condition due to their large active surface and strong adsorption ability against methylene blue (MB).