Synergistic Effect of a Boron‐Doped Carbon‐Nanotube‐Supported Cu Catalyst for Selective Hydrogenation of Dimethyl Oxalate to Ethanol

Abstract

Heteroatom doping is a promising approach to improve the properties of carbon materials for customized applications. Herein, a series of Cu catalysts supported on boron-doped carbon nanotubes (Cu/xB-CNTs) were prepared for the hydrogenation of dimethyl oxalate (DMO) to ethanol. The structure and chemical properties of boron-doped catalysts were characterized by XRD, TEM, N O pulse adsorption, CO chemisorption, H temperature-programmed reduction, and NH temperature-programmed desorption, which revealed that doping boron into CNT supports improved the Cu dispersion, strengthened the interaction of Cu species with the CNT support, introduced more surface acid sites, and increased the surface area of Cu and especially Cu sites. Consequently, the catalytic activity and stability of the catalysts were greatly enhanced by boron doping. 100 % DMO conversion and 78.1 % ethanol selectivity could be achieved over the Cu/1B-CNTs catalyst, the ethanol selectivity of which was almost 1.7 times higher than that of the catalyst without boron doping. These results suggest that doping CNTs with boron is an efficient approach to improve the catalytic performance of CNT-based catalysts for hydrogenation of DMO. The boron-doped CNT-based catalyst with improved ethanol selectivity and catalytic stability will be helpful in the development of efficient Cu catalysts supported on non-silica materials for selective hydrogenation of DMO to ethanol.

One‐Pot Synthesis of Cyclodextrin‐Doped Cu‐SiO2 Catalysts for Efficient Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

“…Ai et al. reported that suitable surface acidity could promote the hydrogenation of DMO . Furthermore, as mentioned above, it possessed large Cu NPs, a low dispersion, and a low copper surface area, as well as a low ratio of Cu + /(Cu + +Cu 0 ).…”

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.…”

Insight into the Correlation between Cu Species Evolution and Ethanol Selectivity in the Direct Ethanol Synthesis from CO Hydrogenation

“…Despite that Al 2 O 3 support has been used for widespread applications, the relatively high quantity of acid sites on Al 2 O 3 surface may catalyze unwanted isomerization or oligomerization reactions according to many studies ,,,. Therefore, in the present study, an inert SiO 2 support with a large surface was considered as a suitable choice ,…”

“…It is generally thought that Cu dispersion and/or the distribution of Cu 0 and Cu + species have great influence on the product selectivity during the hydrogenation process over Cu‐based catalysts . Tuning catalyst preparation parameters (e. g. promoters, Cu loading, calcination temperature) of Cu‐based catalysts is really efficient to modify Cu dispersion and Cu + /(Cu 0 +Cu + ) value. According to the previous literatures, it is plausible that both more dispersed Cu species and higher Cu + /(Cu 0 +Cu + ) value are effective to improve the product selectivity.…”