State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, 457 Zhongshan Road, Dalian 116023, Liaoning, P. R. China.
J Am Chem Soc. 2012 Aug 15;134(32):13366-73. doi: 10.1021/ja304049x. Epub 2012 Jul 31.
We have investigated the photocatalysis of partially deuterated methanol (CD(3)OH) and H(2)O on TiO(2)(110) at 400 nm using a newly developed photocatalysis apparatus in combination with theoretical calculations. Photocatalyzed products, CD(2)O on Ti(5c) sites, and H and D atoms on bridge-bonded oxygen (BBO) sites from CD(3)OH have been clearly detected, while no evidence of H(2)O photocatalysis was found. The experimental results show that dissociation of CD(3)OH on TiO(2)(110) occurs in a stepwise manner in which the O-H dissociation proceeds first and is then followed by C-D dissociation. Theoretical calculations indicate that the high reverse barrier to C-D recombination and the facile desorption of CD(2)O make photocatalytic methanol dissociation on TiO(2)(110) proceed efficiently. Theoretical results also reveal that the reverse reactions, i.e, O-H recombination after H(2)O photocatalytic dissociation on TiO(2)(110), may occur easily, thus inhibiting efficient photocatalytic water splitting.
我们使用新开发的光催化设备结合理论计算，研究了在 400nm 波长下部分氘代甲醇（CD(3)OH）和 H(2)O 在 TiO(2)(110)上的光催化作用。从 CD(3)OH 中明确检测到了在 Ti(5c)位的 CD(2)O、在桥键氧（BBO）位的 H 和 D 原子等光催化产物，而没有发现 H(2)O 光催化的证据。实验结果表明，TiO(2)(110)上 CD(3)OH 的解离是分步进行的，首先是 O-H 解离，然后是 C-D 解离。理论计算表明，C-D 复合的反向势垒较高，以及 CD(2)O 的易脱附使得 TiO(2)(110)上的甲醇光解反应高效进行。理论结果还表明，TiO(2)(110)上 H(2)O 光解后的反向反应，即 O-H 复合，可能很容易发生，从而抑制了高效的光催化水分解。
