Shape- and size-controlled synthesis of Cu nanoparticles wrapped on RGO nanosheet catalyst and their outstanding stability and catalytic performance in the hydrogenation reaction of dimethyl oxalate

Abstract

A novel sonochemical approach was developed for the synthesis of morphology-controlled Cu NPs wrapped on RGO NSs catalysts and their superior stability and catalytic performance in dimethyl oxalate hydrogenation reaction.

Sonochemical catalysis as a unique strategy for the fabrication of nano-/micro-structured inorganics

“…Abbas's group once synthesized morphology-controlled Cu nanoparticles wrapped on reduced graphene oxide (Cu/RGO) when Cu(NO 3 ) 2 and graphene oxide as the precursor went through an in-situ ultrasonication reaction prior to the reduction of pre-product CuO/RGO in a H 2 gas. [171] The morphology and catalytic performance of Cu/RGO were affected by ultrasound, NH 4 OH, and Cu loading. For the pre-product CuO/RGO, the absence of NH 4 OH resulted in polydisperse CuO particles with irregular shapes or amorphous-like structure, and without the aid of ultrasound, the produced Cu catalyst had an elongated-like shape with thick RGO layers owing to the aggregation, whereas ultrasound alone was also not enough to completely reduce the GO into RGO.…”

“…For the pre-product CuO/RGO, the absence of NH 4 OH resulted in polydisperse CuO particles with irregular shapes or amorphous-like structure, and without the aid of ultrasound, the produced Cu catalyst had an elongated-like shape with thick RGO layers owing to the aggregation, whereas ultrasound alone was also not enough to completely reduce the GO into RGO. The Cu/RGO catalysts with a 10 wt% or 25 wt% Cu loading had an excellent dispersion and without any aggregation (Figure S8-IV), [171] but on the contrary, the morphology with a 45 wt% Cu loading appeared to be a leaf-like shape. In the catalytic hydrogenation reaction of dimethyl oxalate, the Cu/RGO catalysts with 25 wt% Cu loading displayed the highest selectivity of methyl glycolate, while the catalysts with 45 wt% Cu loading favored to select ethanol.…”

Recent advances in the catalytic applications of GO/rGO for green organic synthesis

“…Carbon materials have attracted great attention as support materials used in heterogeneous catalysis because of their large surface area and chemical stability by virtue of which high loading of active sites is facilitated [34]. Among carbon materials, graphene and its derivatives (GO/rGO) have extraordinary properties, comparatively activated carbon, carbon black and CNTs that make it a promising candidate for catalysis [70][71][72][83][84][85]. Metal atoms are well recognized for catalyzing the growth of CNTs, and this was the basis for the study of metal-carbon interactions that encouraged applications focused on graphene-supported metals [86].…”

“…In addition, the negatively charged surface of GO can be easily exploited to spread other catalytically active materials on its surface, including NPs of metal and metal oxide, to enhance their resultant properties [68,69]. For this purpose, many metal and/ or metal oxide NPs such as Cu [70], Ni [71], Au [72,73], Ag/CeO 2 [74], Pd [75] and Pt [76] have been incorporated into the GO/rGO. Furthermore, properties similar to that of pristine graphene can be achieved by rGO, which has been further examined for manifold catalytic applications [77][78][79][80].…”

High-performance copper-based catalysts for ethylene glycol and ethanol synthesis via ester hydrogenation reactions

“…可见, 复合载体, 并优化了载体掺杂比例 [19] , 或利用杂原子 掺杂等手段, 提升载体氧空穴数量 [23] . Li等 [21] 利用层 状类水滑石衍生的MnO [9,22,24,27] (网络版彩图) Cu-ZnO催化剂也在酯类加氢中表现出良好的催 化性能 [25,26] 碳纳米管 [29] 、石墨烯 [30] 等碳载体负载的或由金 属有机框架结构 [31] 经碳化衍生的铜基催化剂被应用 于酯加氢反应中. 载体空间限域结构及铜物种与碳载 体表面含氧官能团的相互作用有效促进了铜物种的分 散与稳定, 且多种碳载体或碳化过程均被报道存在铜 物种的自还原现象.…”