Tuning the electronic structure of platinum nanocrystals towards high efficient ethanol oxidation  

铂纳米晶的电子结构调控用于高效乙醇电化学氧化（英文）

作　　者：Sheng Zhang Hai Liu Na Zhang Rong Xia Siyu Kuang Geping Yin Xinbin Ma 张生;刘海;张娜;夏荣;况思宇;尹鸽平;马新宾(天津大学化工学院,绿色合成与转化教育部重点实验室,天津化学化工协同创新中心,天津300072;哈尔滨工业大学化工与化学学院,城市水资源与环境国家重点实验室,黑龙江哈尔滨150001;北京航天动力研究所,北京100076)

机构地区：[1]Key Laboratory for Green Chemical Technology of Ministry of Education,Collaborative Innovation Centre of Chemical Science and Engineering,School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China [2]State Key Laboratory of Urban Water Resource and Environment,School of Chemical Engineering&Technology,Harbin Institute of Technology,Harbin 150001,Heilongjiang,China [3]Beijing Aerospace Propulsion Institute,Beijing 100076,China

出　　处：《Chinese Journal of Catalysis》2019年第12期1904-1911,共8页催化学报（英文）

基　　金：grateful to the financial support from the Key Research and Development Project of Tianjin(18ZXJMTG00180);the National Nature Science Foundation of China(21433003)~~

摘　　要：Direct ethanol fuel cell is a promising low temperature fuel cell,but its development is hindered by sluggish kinetics of anode catalysts for ethanol oxidation.Here a high efficient platinum/tin oxide/Graphene nanocomposite is synthesized through a facile and environmentally benign method.The structure and morphology are carefully characterized by X-ray diffraction and Transmission electron microscopy,showing a clear platinum/tin oxide heterostructure uniformly dispersed on graphene support.This catalyst demonstrates the highest activity among the reported catalysts and much higher durability towards ethanol oxidation compared to conventional platinum nanocatalysts.The ultrahigh activity originates from promoted removal of poisoning carbon monoxide immediate species on platinum due to a strong electronic donating effect from both tin oxide and graphene,which is fully supported by carbon monoxide stripping and X-ray photoelectron spectroscopy analysis.Our platinum/tin oxide/Graphene appears to be a promising candidate for ethanol oxidation electrocatalysts.直接乙醇燃料电池是一种高效、绿色的低温燃料电池,但其发展受到阳极电催化氧化乙醇缓慢动力学的限制.目前,Pt基材料是最适合用于乙醇氧化反应(EOR)的电催化剂.然而其活性中心容易被反应过程中生成的中间体CO吸附而中毒,在很大程度上降低了催化剂的活性和稳定性.减轻Pt中毒的一种有效方法是引入第二种金属(如Sn,Ru,Rh等)以形成双金属催化剂.其中,Pt-Sn双金属催化剂由于其优异的乙醇氧化性能而得到了广泛研究.根据相关报道,与Pt相邻的Sn原子有利于H2O在其表面吸附解离并形成OHads活性物种,从而促进Pt表面反应中间体CO的氧化并重新释放出活性位.在金属氧化物中,氧化锡(SnOx)由于其在酸性电解质中较高的稳定性而被广泛用作DAFC中的助催化剂.目前,大多数研究认为,引入第二金属后催化活性的增强源于几何效应,而其中电子效应的影响却不明确.因此,深入了解Pt和SnOx之间的电子效应对于提高乙醇的电催化性能具有重要意义.本文首先通过乙二醇法合成了Pt/SnOx/石墨烯纳米复合材料,通过X-射线衍射(XRD)和透射电子显微镜(TEM)对催化剂的结构和形貌进行了表征.结果表明,Pt/SnOx异质结构均匀分散在石墨烯载体上.XPS表明,催化剂中的Pt主要以Pt0形式存在,其被认为是乙醇氧化的主要活性位点.同时,Pt/SnOx/石墨烯中Pt 4f的结合能相对于Pt/C催化剂负向移动了0.37 eV,这主要是由于存在从石墨烯和SnOx到Pt的电子转移,证明了载体和金属氧化物对Pt活性中心的电子改性.电化学循环伏安(CV)曲线中,正扫的氧化峰反映了电催化剂对乙醇的氧化能力.Pt/SnOx/石墨烯和Pt/石墨烯的峰电流密度分别是商业Pt/XC-72催化剂的2.82和1.82倍,表明Pt/SnOx/石墨烯具有更加优异的乙醇电催化氧化活性.此外,Pt/SnOx/石墨烯的正向氧化峰电位比Pt/石墨烯和Pt/XC-72低约30至40 mV,表明SnOx和石墨烯的引入降�

关 键 词：Platinum nanocrystals Ethanol oxidation ELECTROCATALYST Pt/tin oxide heterostructure Electronic effect 

分 类 号：O64[理学—物理化学]