Graphene oxide-ordered mesoporous silica composite supported Co-based catalysts for CO hydrogenation to higher alcohols

Abstract

Abstract Higher alcohols synthesis (HAS) directly from syngas has attracted lots of attentions due to its advantages on environmental-friendliness, versatility and economy. Recently, researches proposed that the Co-Co2C dual sites could act as efficient active species for HAS. But the role of carbides as well as its formation process needs further investigation. Here, we synthesized a series of graphene oxide (GO)-ordered mesoporous silica (OMS) composite supported cobalt-based catalysts, which presented excellent activity and selectivity in HAS. It is found that the addition of GO could not only improve the dispersion of cobalt species, but also act as an electron donor to promote CO adsorption and disassociation on Co species, both leading to a higher catalytic activity. The electron donor effect of GO could facilitate the carbide formation process as well. The increased ratio of Co2C/Co with GO addition linearly improved the alcohol selectivity in HAS. However, excess GO addition would cover a part of active sites and weaken the electron donor effect, resulting in a lower alcohol yield. This work gives insights into the effects of carbon materials on active sites distribution and performance of cobalt-based catalysts, which could be used to rationalize the design of catalysts for HAS.