碳结构锯齿形边缘对SO2的催化氧化机制研究

利用多孔碳实现SO2脱除和高值资源化具有耗水少、吸附剂可循环等优点,是当前重要技术方向,探究SO2在碳材料纳米空间中的吸附转化机制是该技术的理论基础。前期研究表明O2存在的条件下,碳材料中SO2会被催化氧化形成SO3,但具体的吸附催化位点和氧化路径有待进一步研究。本文采用密度泛函理论计算了SO2碳材料锯齿形不饱和碳原子处的吸附和催化氧化路径,发现:SO2和O2在不饱和碳原子处发生化学吸附。当O2在不饱和碳原子处优先吸附时,SO2会与活化的O2反应生成SO3和化学吸附态的O;当SO2在不饱和碳原子处优先吸附时,O2会在S原子附近活化,活化后的O2会与SO2反应生成气相SO3、化学吸附态SO3。本文计算结果为用于硫资源化的高性能碳材料合成提供了理论指导。

SO2 Oxidation at Zigzag Edge of Carbon Materials:a Mechanistic Study

The utilization of porous carbon materials to achieve the conversion from pollutant SO2 to high-value S containing resource possesses the advantages of low water consumption and the availability to recycle the adsorbent is regarded as an important technical direction.The mechanisms of SO2 adsorption and conversion in nano-spaces are the theoretical basis of this technology.It has been found that SO2 can be catalytically oxidized to SO3 at the presence of O2,but the active sites and detailed reaction mechanism remain to be investigated.In this work,the pathways of SO2 adsorption and oxidation at the zigzag unsaturated carbon atom was calculated using density functional theory(DFT).The results show that SO2 and O2 both can chemisorb at the zigzag unsaturated carbon atom.When the O2 molecule is firstly chemisorbed at the unsaturated carbon atom,the activated O2 can react with SO2 molecule,generating SO3 and chemisorbed O atom.In the case that SO2 is firstly chemisorbed at the unsaturated carbon atom,O2 can be activated at the S atom in SO2,and then activated O2 molecule can react with SO2,forming gas SO3 and chemisorbed SO3.The calculated results in this work provide theoretical guide to the preparation of carbon materials for converting SO2 to high-value S containing resource.