柴油超深度加氢脱硫研究取得新进展 - 图文(2)

mal synthesis ? Raman spectroscopy ? reaction mechanisms ? UV/Vis spectroscopy t itu UV Raman spectroscopy has been found to be a potential tool to study the evolution of both the organic te

ganic framework simultaneously, thus revealing the interaction between the organic template and framework

n.

his manuscript, we propose, for the first time, a detailed synthesis mechanism of AlPO-5 using in situ UV Rama

copy. The building blocks from the intermediates to the final crystals were well identified by taking the advanta

erful technique. . A very important intermediate composed of 4-membered rings for the channel formation has

The intermediate was formed due to the existence of the templates which provide steric support for channel fo

ecific molecular vibrations in the very early stages. The building blocks from the intermediate to the final cryst

ntified by taking the advantage of this powerful technique. This work provides molecular-level insights into the

late in channel formation. We anticipate that this will facilitate the choice of organic templates and tailoring the

blocks for the rational synthesis of zeolites.

太阳能光催化制氢研究取得新进展

我组利用双共催化剂发展了Pt-PdS/CdS三元光催化剂，在可见光照射下，利用Na2S作为牺牲试剂，产氢量子效率达到93%，这是迄今为止报道的光催化产氢最高的量子效率。该工作以priority communication发表在近期的《Journal of Catalysis》上（J. Catal., DOI: 10.1016/j.jcat.2009.06.024）。美国C&E News立即进行了a full-page story的报道。其中，日本东京大学光催化研究专家K. Domen 教授也给予了高度评价，认为该工作提供了一种人工设计高效光催化剂的方法。这是李灿研究组继在光催化剂表面异相结（Angew. Chem. Int. Ed.2008，DOI: 0.1002/anie.200704788）和异质结及其光催化制氢性能（J. Am. Chem. Soc. 2008，DOI: 10.1021/ja8007825）的研究工作之后在太阳能光催化制氢方面取得的又一重要进展。

太阳能光催化制氢作为解决能源危机和环境问题的一个重要途径，受到世界各国的高度重视。提高可见光区量子效率是这一领域的研究目标和最大挑战之一。在光催化过程的两个半反应中（电子还原和空穴氧化），氧化半反应被认为是光催化过程的主要瓶颈。我们通过精心设计组装光催化剂，在光催化剂 (CdS) 表面共担载还原 (Pt) 和氧化 (PdS) 双组份共催化剂，有效地解决了电子和空穴的分离和传输问题，利用牺牲试剂在可见光照射下取得了93%的产氢量子效率，已经接近自然界光合作用原初过程的量子效率水平。该工作发展了一种高效光催化重整硫化氢溶液制氢的技术，由于氧化共催化剂的担载有效地避免了光催化剂的光腐蚀现象，使该三元催化剂表现出很高的稳定性，显示出重要的工业应用前景。

这项工作提出了一种人工模拟光合作用设计高效光催化剂的思路，即通过分别组装合适的氧化和还原双共催化剂在空间上避免光生电荷复合，可以极大地提高光生电荷的分离和传输效率，从而大幅提高量子效率。这对发展太阳能高效光催化剂及光催化制氢和还原CO2过程具有重要指导意义。(文/杨金辉 图/ 杨金辉 余松华)

Visible-light-driven hydrogen production with extremely high quantum efficiency on Pt–PdS/CdS photocatalyst

Hongjian Yan, Jinhui Yang, Guijun Ma, Guopeng Wu, Xu Zong, Zhibin Lei, Jingying Shi and Can Li*

Journal of Catalysis., 2009 in press

Communication. http://dx.doi.org/10.1016/j.jcat.2009.06.024

Abstract: To efficiently convert solar energy into chemical energy by artificial photosynthesis, we need to develop visible-light-responsive

photocatalysts with a high quantum efficiency (QE). Here we report that an artificial photocatalyst (Pt–PdS/CdS) can achieve a QE up to 93% in photocatalytic H2 production in the presence of sacrificial reagents under visible light irradiation, and is very stable under the photocatalytic reaction conditions. The extremely high QE could be achieved by loading as low as 0.30 wt% of Pt and 0.13 wt% of PdS as cocatalysts on CdS.

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