Structural and mechanistic understanding of an active and durable graphene carbocatalyst for reduction of 4-nitrophenol at room temperature  

作　　者：Huawen Hu John H. Xin Hong Hu Xiaowen Wang 

机构地区：[1]Nanotechnology Centre, Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong SAR 999077, China

出　　处：《Nano Research》2015年第12期3992-4006,共15页纳米研究（英文版）

摘　　要：The development of an active, durable, and metal-free carbocatalyst that is able to replace metal-based catalysts is of increasing scientific and technological importance. The use of such a catalyst would avoid problems caused by metal- containing catalysts, for example, environmental pollution by heavy metals and depletion of rare metal resources. Herein, an active and durable graphene carbocatalyst is presented for the carbocatalytic conversion of 4-nitrophenol to 4-aminophenol at ambient temperature. The carbocatalyst was prepared via a mild, water-based reaction between L-ascorbic acid （AA） and graphene oxide （GO） and did not involve any other reactants. During the structure and catalytic property optimization, a series of carbocatalysts were fabricated at various reaction temperatures and AA/GO ratios. Using several characterization techniques, detailed structural features of these carbocatalysts were identified. Possible active species and sites on the carbocatalysts were also identified such as certain oxygen-containing groups, the ~x-conjugated system, and graphene sheet edges. In addition, the synergistic effect between these active species and sites on the resulting catalytic activity is highlighted. Furthermore, we clarified the origin of the high stability and durability of the optimized carbocatalyst. The work presented here aids the design of high-performance carbocatalysts for hydrogenation reactions, and increases understanding of the structural and mechanistic aspects at the molecular level that lead to high catalyst activity and durability.能代替基于金属的催化剂的活跃、持久、没有金属的 carbocatalyst 的发展具有增加科学、工艺的重要性。如此的催化剂的使用将避免例如，包含金属的催化剂引起的问题由稀罕金属资源的重金属和弄空的环境污染。此处，活跃、持久的 graphene carbocatalyst 在周围的温度为 4-nitrophenol 的 carbocatalytic 变换被介绍给 4-aminophenol。carbocatalyst 经由在 L 维生素酸(AA ) 和 graphene 氧化物之间的温和、以水为基的反应被准备(去) 并且没包含任何另外的反应物。在结构和催化性质优化期间，一系列 carbocatalysts 在各种各样的反应温度和 AA/GO 比率被制作。用几种描述技术，详细说明了这些 carbocatalysts 的结构的特征被识别。carbocatalysts 上的可能的活跃种类和地点也被识别例如某些包含氧的组，结合的系统，和 graphene 表边。另外，在这些之间的 synergistic 效果结果上的活跃种类和地点催化活动被加亮。而且，我们澄清了高稳定性的起源和优化 carbocatalyst 的耐久性。这里介绍的工作为加氢反应帮助高效的 carbocatalysts 的设计，并且在分子的水平增加结构、机械学的方面的理解导致高催化剂活动和耐久性。

关 键 词：metal-free graphene carbocatalyst activity and durability L-ascorbic acid active sites and domains synergistic effect carbocatalytic conversion of 4-nitrophenol （4NP） to 4-aminophenol （4AP） 

分 类 号：TQ222[化学工程—有机化工] O613.71[理学—无机化学]