Ag-loading on brookite TiO2 quasi nanocubes with exposed {210} and {001} facets: Activity and selectivity of CO2 photoreduction to CO/CH4
Ag-loading on brookite TiO2 quasi nanocubes with exposed {210} and {001} facets: Activity and selectivity of CO2 photoreduction to CO/CH4
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具有暴露的{210}和{001}面的板钛矿TiO2准纳米立方体上的Ag负载：CO2光还原成CO/CH4的活性和选择性
DOI：
10.1016/j.apcatb.2015.06.022
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发表时间：
2016-01-01
影响因子：
22.1
通讯作者：
Zhang, Jing
中科院分区：
文献类型：
--
作者：
Li, Kan;Peng, Tianyou;Zhang, Jing
以4个{2 1 0}晶面和2个{0 0 1}裸露晶面为主的板钛矿型准纳米立方体(平均尺寸约为5 0 nm)作为CO2光还原催化剂.结果表明，不同载银量对纳米立方体裸露面上的银纳米粒子的大小和分布有显著影响，从而导致二氧化碳光还原生成CO/CH4的活性和选择性存在明显差异。在负载量为0.5%时，沸石纳米立方体的总活性最高，CO/CH4的产率为128.8/11.5ppmh(-1)，是原始沸石的3.89倍。当载银水平为0.5%时，载银可以形成聚集在{210}面上的银纳米粒子，同时一些银纳米粒子分散在{001}面上，从而提高了甲烷生成的选择性。借助各种表征技术对这一新现象进行了探索。这一结果为研究负载银对沸石纳米立方体裸露面上CO2光还原反应的活性和选择性的影响提供了一个重要的指标，并展示了一种通过调节沸石二氧化钛的形貌和表面结构来调节CO2光还原性能的策略。(C)2015爱思唯尔B.V.保留所有权利。
Brookite TiO2 quasi nanocubes (mean size of similar to 50 nm) mainly surrounded by four {2 1 0} and two {0 0 1} exposed crystal facets were used as catalyst for the CO2 photoreduction. It is found that the Ag nanopartide size and its distribution on the exposed facets of the brookite nanocubes are significantly influenced by the Ag-loading levels, which then causing obvious differences in the activity and selectivity of CO2 photoreduction to CO/CH4 generation. At 0.5% Ag-loading, the brookite nanocubes show the highest overall activity with CO/CH4 production rates of 128.8/11.5 ppm h(-1), which is 3.89 times higher than that of the pristine brookite. When the Ag-loading level is 0.5% Ag-loading could lead to the formation of Ag nanoparticles aggregated on the {2 1 0} facets with some Ag nanoparticles dispersed on the {0 0 1} facets, and then causing more selectivity for the CH4 generation. This novel phenomenon was explored with the aid of various characterization techniques. The present results provide an important indication about the effects of Ag-loading on the activity and selectivity of CO2 photoreduction reaction over the exposed facets of brookite nanocubes, and demonstrate a strategy for tuning the CO2 photoreduction performance through tailoring the morphology and surface structure of brookite TiO2. (C) 2015 Elsevier B.V. All rights reserved.