钴高度分散于还原氧化石墨烯用于高级氧化降解有机污染物

High dispersion of cobalt on the reduced graphene oxide for advanced oxidation degradation of organic pollutants

在废水处理技术中,基于过氧单硫酸盐(PMS)的高级氧化工艺被认为是降解有机污染物中最高效且绿色的方法之一。在激活PMS的方法中,负载过渡金属的催化剂由于金属离子溶出量低而广受关注,但却面临金属物种易团聚引发的降解活性低的问题。将Co负载在还原氧化石墨烯(rGO)上,经简单方法分别合成了Co高分散的QSCo-rGO和Co团聚的AGCo-rGO。XRD、HRTEM和元素分布研究表明,QSCo-rGO中的Co未发生金属团聚现象,实现了高度分散;而AGCo-rGO中的Co以CoO纳米颗粒的形式团聚。在激活PMS降解苯酚的反应中,QSCo-rGO可在30 min内完成100%的降解,而AGCo-rGO需要90 min。此外,QSCo-rGO展现出较好的可重复性和使用广泛性。机理研究表明,催化剂QSCo-rGO中的Co高度分散,暴露出更多活性金属位点,其通过激活PMS产生非自由基^(1)O_(2)从而高活性降解苯酚。本文可为设计增强降解活性的高级氧化催化剂提供思路。

In wastewater treatment,the advanced oxidation process based on peroxymonosulfate(PMS)is considered to be one of the most efficient and green methods for degrading organic pollutants.Among the methods of activating PMS,transition metal-supported catalysts have attracted much attention due to the low dissolution of metal ions,but they face the problem of low degradation activity,which is caused by the easy aggregation of metal species.In this work,Co was loaded on reduced graphene oxide(rGO),and Co highly dispersed QSCo-rGO and Co agglomerated AGCo-rGO were synthesized by a simple method.XRD,HRTEM and element mapping studies showed that Co in QSCo-rGO was highly dispersed without metal agglomeration.The Co in AGCo-rGO was aggregated in the form of CoO nanoparticles.In the reaction of activating PMS to degrade phenol,QSCo-rGO could complete 100%degradation efficiency within 30 min,while AGCo-rGO required up to 90 min.In addition,QSCo-rGO exhibited good reusability and versatility.The mechanism study indicated that Co in QSCo-rGO catalyst was highly dispersed,which exposed more active sites,and it generated non-free radical ^(1)O_(2) by activating PMS to degrade phenol with high activity.This work provides a new idea for designing advanced oxidation catalysts with enhanced degradation activity.