|
|
[交流]
大化所包信和院士最新ACCOUNTS OF CHEMICAL RESEARCH綜述 已有12人參與
包信和院士長期從事表面化學(xué)與催化基礎(chǔ)和應(yīng)用研究,在催化選擇氧化、界面和納米催化以及甲烷催化活化等理論和實(shí)踐中取得了系統(tǒng)、深入、具有創(chuàng)新意義的成果。近年來,包信和院士帶領(lǐng)的研究團(tuán)隊(duì)研制和開發(fā)了多種原位、動(dòng)態(tài)催化研究方法,如原位高壓NMR、動(dòng)態(tài)光發(fā)射電子顯微鏡PEEM等,發(fā)現(xiàn)并從理論上證實(shí)了碳納米管的限域效應(yīng),提出了納米催化體系的“協(xié)同束縛”概念,成功研制出CO脫除和合成氣高效轉(zhuǎn)化催化劑。其取得的理論和實(shí)驗(yàn)成果在國際、國內(nèi)相關(guān)領(lǐng)域形成了重要影響。
Title:Interface-Confined Oxide Nanostructures for
Catalytic Oxidation Reactions
Abstract:eterogeneous catalysts, often consisting of metal nanoparticles supported on high-surface-area oxide solids, are common in industrial chemical reactions. Researchers have increasingly recognized the importance of oxides in heterogeneous catalysts: that they are not just a support to help the dispersion of supported metal nanoparticles, but rather interact with supported metal nanoparticles and affect the catalysis. The critical role of oxides in catalytic reactions can become very prominent when oxides cover metal surfaces forming the inverse catalysts.
The source of the catalytic activity in homogeneous catalysts and metalloenzymes is often coordinatively unsaturated (CUS) transition metal (TM) cations, which can undergo facile electron transfer and promote catalytic reactions. Organic ligands and proteins confine these CUS cations, making them highly active and stable. In heterogeneous catalysis, however, confining these highly active CUS centers on an inorganic solid so that they are robust enough to endure the reaction environment while staying flexible enough to perform their catalysis remains a challenge.
In this Account, we describe a strategy to confine the active CUS centers on the solid surface at the interface between a TM oxide (TMO) and a noble metal (NM). Among metals, NMs have high electron negativity and low oxygen affinity. This
means that TM cations of the oxide bind strongly to NM atoms at the interface, forming oxygen-terminated-bilayer TMO nanostructures. The resulting CUS sites at the edges of the TMO nanostructure are highly active for catalytic oxidation reactions. Meanwhile, the strong interactions between TMOs and NMs prevent further oxidation of the bilayer TMO phases, which would otherwise result in the saturation of oxygen coordination and the deactivation of the CUS cations. We report that we can also tune the oxidemetal interactions to modulate the bonding of reactants with CUS centers, optimizing their catalytic performance.
We review our recent progress on oxide-on-metal inverse catalysts, mainly the TMO-on-Pt (TM = Fe, Co, and Ni) systems and discuss the interface-confinement effect, an important factor in the behavior of these catalytic systems. We have studied both model catalyst systems and real supported nanocatalysts. Surface science studies and density functional theory calculations in model systems illustrate the importance of the oxidemetal interfaces in the creation and stabilization of
surface active centers, and reveal the reaction mechanism at these active sites. In real catalysts, we describe facile preparation processes for fabricating the oxide-on-metal nanostructures. We have demonstrated excellent performance of the inverse catalysts in oxidation reactions such as CO oxidation. We believe that the interface confinement effect can be employed to design highly efficient novel catalysts and that the inverse oxide-on-metal catalysts may find wide applications
in heterogeneous catalysis.![]()
1.gif
[ Last edited by jiaxe2003 on 2013-3-9 at 23:30 ] |
» 本帖附件資源列表
-
歡迎監(jiān)督和反饋:小木蟲僅提供交流平臺(tái),不對(duì)該內(nèi)容負(fù)責(zé)。
本內(nèi)容由用戶自主發(fā)布,如果其內(nèi)容涉及到知識(shí)產(chǎn)權(quán)問題,其責(zé)任在于用戶本人,如對(duì)版權(quán)有異議,請(qǐng)聯(lián)系郵箱:xiaomuchong@tal.com
- 附件 1 : ar300249b.pdf
2013-03-05 19:35:12, 1023.16 K
» 本帖已獲得的紅花(最新10朵)
» 猜你喜歡
» 本主題相關(guān)價(jià)值貼推薦,對(duì)您同樣有幫助:
|