Wang Yuquan, Zhang Zhengjun, Zhu Yu, Li Zhengcao, Vajtai Robert, Ci Lijie, Ajayan Pulickel Madhavapanicker
Advanced Materials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, P.R. China.
ACS Nano. 2008 Jul;2(7):1492-6. doi: 10.1021/nn800223s.
Vanadium dioxide (VO(2)) is a well-known semiconductor material with a band gap of 0.7 eV, and is seldom used as a photocatalyst. We report here a new crystal structure for nanostructured VO(2), with body-centered-cubic (bcc) structure and a large optical band gap of approximately 2.7 eV, which surprisingly shows excellent photocatalytic activity in hydrogen production. The bcc VO(2) phase exhibited a high quantum efficiency of approximately 38.7% when synthesized as nanorods. Using films of the aligned VO(2) nanorods, the hydrogen production rate can be tuned by varying the incident angle of UV light on the films and reaches a high rate of 800 mmol/m(2)/h from a mixture of water and ethanol under UV light, at a power density of approximately 27 mW/cm(2), allowing possible commercial application of this material as photoassisted hydrogen generators.
二氧化钒（VO₂）是一种著名的半导体材料，带隙为0.7电子伏特，很少用作光催化剂。我们在此报告一种纳米结构VO₂的新晶体结构，具有体心立方（bcc）结构和大约2.7电子伏特的大光学带隙，令人惊讶的是，它在制氢方面表现出优异的光催化活性。当合成纳米棒时，bcc VO₂相表现出约38.7%的高量子效率。使用排列的VO₂纳米棒薄膜，通过改变紫外光在薄膜上的入射角可以调节产氢速率，在紫外光下，从水和乙醇的混合物中，在约27毫瓦/平方厘米的功率密度下，产氢速率可达800毫摩尔/平方米/小时，使得这种材料有可能作为光辅助制氢发生器进行商业应用。
