Black TiO2−x with stable surface oxygen vacancies as the support of efficient gold catalysts for water-gas shift reaction†,Catalysis Science & Technology

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Black TiO2−x with stable surface oxygen vacancies as the support of efficient gold catalysts for water-gas shift reaction†
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2018-01-05 00:00:00 , DOI: 10.1039/c7cy02429k
Lei Li _{1,

2,

3,

4} , Li Song _{1,

2,

3,

4} , Longfeng Zhu _{1,

2,

3,

4} , Zheng Yan _{1,

2,

3,

4} , Xuebo Cao _{1,

2,

3,

4}

Affiliation

Exploring appropriate supports is a key step to prepare efficient water-gas shift (WGS) catalysts. In this sense, supports with some oxygen vacancies are preferable, but there have been no efficient methods to obtain abundant stable surface oxygen vacancies. Here, a black TiO_2−x support rich in stable surface oxygen vacancies was prepared by hydrogen-etching technology. More impressively, compared with the gold catalyst supported on traditional white TiO₂, the gold catalyst supported on black TiO_2−x has been proven to be an efficient and stable WGS catalyst. According to the in-depth characterization of its structural properties, the disordered layer and abundant stable surface oxygen vacancies of the black TiO_2−x support lead to higher microstrain and more metallic Au⁰ species, respectively, which are all in favor of higher WGS catalytic activities. Furthermore, we successfully linked the WGS thermocatalytic activities with the optoelectronic properties, and then tried to understand the WGS pathway from the view of an electron flow process. Hereinto, the Ohmic barrier has been decreased because of the narrowed forbidden band gap, which improves the transmission efficiency of “hot-electron flow”. Meanwhile, the abundant surface oxygen vacancies function as electron traps, thus promoting the flow of “hot-electrons” and reduction reaction of H₂O. As a consequence, the WGS catalytic activity is enhanced. The involved hydrogen-etching method resulting in abundant stable surface oxygen vacancies can be extended to other supported catalysts for WGS reaction or other thermocatalytic reactions.

中文翻译：

具有稳定的表面氧空位的黑色TiO _{2- x}作为水煤气变换反应的有效金催化剂的载体†

探索合适的载体是制备高效水煤气变换（WGS）催化剂的关键步骤。从这个意义上讲，具有一些氧空位的载体是优选的，但是还没有有效的方法来获得大量稳定的表面氧空位。在此，通过氢蚀刻技术制备了富含稳定的表面氧空位的黑色TiO _{2- x}载体。更令人印象深刻的是，与传统的白色TiO ₂上负载的金催化剂相比，负载在黑色TiO _{2- x}上的金催化剂已被证明是一种高效，稳定的WGS催化剂。根据其结构性质的深入表征，黑色TiO ₂₋的无序层和丰富的稳定表面氧空位_x载体分别导致更高的微应变和更多的金属Au⁰物种，所有这些都有利于更高的WGS催化活性。此外，我们成功地将WGS的热催化活性与光电特性联系起来，然后尝试从电子流动过程的角度了解WGS的途径。其中，由于禁带宽度变窄，欧姆势垒减小，从而提高了“热电子流”的传输效率。同时，大量的表面氧空位起电子陷阱的作用，从而促进了“热电子”的流动和H_2的还原反应。O.结果，提高了WGS的催化活性。所涉及的氢蚀刻法可产生大量稳定的表面氧空位，可扩展至用于WGS反应或其他热催化反应的其他负载型催化剂。

更新日期：2018-01-05

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