School of Civil & Environmental Engineering, Nanyang Technological University, Singapore.
Chemistry. 2013 Feb 25;19(9):3061-70. doi: 10.1002/chem.201204013. Epub 2013 Jan 30.
We report a facile non-hydrothermal method for the large-scale production of hierarchical TiO(2) nanorod spheres for the photocatalytic elimination of contaminants and killing bacteria. Crescent Ti/RF spheres were prepared by deliberately adding titanium trichloride (TiCl(3)) to the reaction of resorcinol (R) and formaldehyde (F) in an open reactor under heating and stirring. The hierarchical TiO(2) nanorod spheres were obtained by calcining the crescent Ti/RF spheres in a furnace in air to burn off the RF spheres. This method has many merits, such as large-scale production, good crystallisation of TiO(2), and good reproducibility, all of which are difficult to realise by conventional hydrothermal methods. The calcination temperature plays a significant role in influencing the morphology, crystallisation, porosity, Brunauer-Emmett-Teller (BET) specific surface area, and hierarchy of the TiO(2) nanorod spheres, thus resulting in different photocatalytic performances under UV light and solar light irradiation. The experimental results have demonstrated that the hierarchical TiO(2) nanorod spheres obtained after calcination of the crescent Ti/RF spheres at different temperatures displayed similar photocatalytic activities under irradiation with UV light. We attribute this to a balance of opposing effects of the investigated factors. A higher calcination temperature leads to greater light absorption capability of the TiO(2) nanorod spheres, thus resulting in higher photocatalytic antibacterial activity under solar light irradiation. It is also interesting to note that the hierarchical TiO(2) nanorod spheres displayed intrinsic antibacterial activity in the absence of light irradiation, apparently because their sharp outward spikes can easily pierce and penetrate the walls of bacteria. In this study, the sharpest hierarchical TiO(2) nanorod spheres were obtained after calcination at 500°C, and these exhibited the highest antibacterial activity without light irradiation. A higher calcination temperature proved detrimental to the sharpness of the TiO(2) nanorods, thus reducing their intrinsic antibacterial activity.
我们报告了一种简便的非水热法，用于大规模生产用于光催化消除污染物和杀菌的分级 TiO(2)纳米棒球。通过在敞开式反应器中加热和搅拌，故意将三氯化钛（TiCl(3)）添加到间苯二酚（R）和甲醛（F）的反应中，制备了新月形 Ti/RF 球。通过在空气中将新月形 Ti/RF 球在炉中煅烧以烧掉 RF 球，得到分级 TiO(2)纳米棒球。该方法具有许多优点，例如大规模生产、TiO(2)结晶良好、重现性好，这些都是常规水热法难以实现的。煅烧温度对 TiO(2)纳米棒球的形态、结晶度、孔隙率、BET 比表面积和分级结构有显著影响，因此在紫外光和太阳光照射下表现出不同的光催化性能。实验结果表明，在不同温度下煅烧新月形 Ti/RF 球得到的分级 TiO(2)纳米棒球在紫外光照射下表现出相似的光催化活性。我们认为这是由于研究因素的相反影响达到平衡。较高的煅烧温度导致 TiO(2)纳米棒球具有更高的光吸收能力，因此在太阳光照射下具有更高的光催化杀菌活性。有趣的是，还注意到分级 TiO(2)纳米棒球在没有光照的情况下表现出固有杀菌活性，显然是因为它们尖锐的向外刺很容易刺穿和穿透细菌的细胞壁。在本研究中，在 500°C 煅烧得到的分级 TiO(2)纳米棒球最尖锐，在没有光照的情况下表现出最高的杀菌活性。较高的煅烧温度不利于 TiO(2)纳米棒的尖锐度，从而降低了其固有杀菌活性。
