Sambandam Balaji, Michael Robin Jude Vimal, Manoharan Periakaruppan T
Department of Chemistry, Indian Institute of Technology-Madras, Chennai-60036, India.
Nanoscale. 2015 Sep 7;7(33):13935-42. doi: 10.1039/c5nr02666k. Epub 2015 Jul 29.
ZnO nanorods and Mn/ZnO microflowers with nano-sized petals exhibit singly ionized oxygen vacancies, V. This is strongly supported by a green photoluminescence emission at 2.22 eV and an EPR g value of 1.953, both of which are suppressed greatly after annealing in an oxygen atmosphere. A strong red emission observed during exposure to X-rays reveals the presence of F(+) centres as a consequence of the V. Mn/ZnO displayed enhanced H2 generation with visible light exposure, when compared to pure ZnO and annealed Mn/ZnO in the visible region, which directly correlated with the oxygen vacancy concentration. There is an interesting correlation between the intensities of the EPR lines at the g-value of 1.953 due to the oxygen vacancies, the intensity of light emitted from the exposure to X-rays, the intensity of the photoluminescence due to oxygen vacancies and the quantity of H2 produced by the photocatalytic effect when comparing the three different nanomaterials, viz. pure ZnO, Mn/ZnO before and after annealing, all having been made exactly by the same methodologies.
具有纳米尺寸花瓣的氧化锌纳米棒和锰掺杂氧化锌微花呈现出单电离氧空位V。这得到了2.22电子伏特处的绿色光致发光发射以及1.953的电子顺磁共振g值的有力支持，在氧气气氛中退火后，这两者都大大受到抑制。在X射线照射期间观察到的强烈红色发射表明，由于氧空位V的存在，出现了F(+)中心。与纯氧化锌以及在可见光区域中退火的锰掺杂氧化锌相比，锰掺杂氧化锌在可见光照射下表现出增强的氢气生成，这与氧空位浓度直接相关。在比较三种不同的纳米材料（即纯氧化锌、退火前后的锰掺杂氧化锌，所有这些都是通过完全相同的方法制备的）时，由于氧空位导致的g值为1.953处的电子顺磁共振线强度、X射线照射发出的光强度、由于氧空位导致的光致发光强度以及光催化效应产生的氢气量之间存在有趣的相关性。
