摘要
在甲烷干重整反应(DRM)中,常规浸渍法制备的Ni/Al2O3催化剂常因过多积炭导致催化剂失活,因此研究如何提高Ni/Al2O3催化剂的抗积炭能力具有重要意义。通过浸渍法和高温碳化法制备的氮掺杂碳表面修饰的Ni/Al2O3催化剂Ni/Al2O3@NC-3和Ni/Al2O3@NC-5(3和5分别代表多巴胺聚合时间为3 h和5 h)在DRM中表现出了较强的抗积炭性能。使用X射线衍射(XRD)、拉曼(Raman)光谱、X射线光电子能谱(XPS)、热重(TG)和扫描电镜(SEM)等表征手段对催化剂的结构和电性质进行了分析,并探讨了氮掺杂碳的引入对催化剂稳定性和抗积炭性能的影响。XPS结果表明,Ni/Al2O3@NC-3和Ni/Al2O3@NC-5催化剂中金属Ni与氮掺杂碳发生了电子相互作用,形成了催化惰性的Ni+物种,由此减缓了CH_(4)的裂解速率,进而有效地减少了积炭的产生。在经8 h活性测试后,Ni/Al2O3@NC-3催化剂的CH_(4)转化率和CO_(2)转化率分别维持在52.2%和62.3%,且反应后Ni/Al2O3@NC-3催化剂的积炭量仅为7%(质量分数,下同),远远低于Ni/Al2O3催化剂的积炭量(25%)。
In methane dry reforming reaction(DRM),the Ni/Al2O3 catalysts prepared by conventional impregnation method easily suffers from deactivation due to the serious carbon depositions,so it is important to research how to improve the resistance to coking ability of Ni/Al2O3 catalysts.Ni/Al2O3 catalysts(Ni/Al2O3@NC-3 and Ni/Al2O3@NC-5)modified with nitrogen-doped carbons surface by impregnation method and high-temperature carbonization method(3 and 5 represent dopamine polymerization times of 3 h and 5 h,respectively)exhibited a strong resistance to coking in DRM.The structure and electronic property of catalysts were revealed by X-ray diffraction(XRD),Raman spectroscopy(Raman),X-ray photoelectron spectroscopy(XPS),thermogravimetry(TG)and scanning electron microscopy(SEM),and the effect of the introduced nitrogen-doped carbons on the resistance to coking and catalytic stability of the Ni/Al2O3 catalysts was investigated.The results of XPS show that the metallic Ni and nitrogen-doped carbons in+Ni/Al2O3@NC-3 and Ni/Al2O3@NC-5 catalysts interact electronically and form catalytically inert Ni species to slow down the rate of CH_(4) cracking and thus effectively reduce the generation of carbon depositions.After 8 h activity test,the CH_(4) conversion rate and CO_(2) conversion rate of Ni/Al2O3@NC-3 catalysts are maintained at 52.2%and 62.3%,respectively,and the amount of carbon depositions in the used Ni/Al2O3@NC-3 catalysts is only 7%(mass fraction,same below),which is much lower than that of Ni/Al2O3 catalysts(25%).
作者
任永旺
王一泽
常飞祥
俞择修
魏勤洪
REN Yongwang;WANG Yize;CHANG feixiang;YU Zexiu;WEI Qinhong(School of Naval Architecture and Maritime,Zhejiang Ocean University,Zhoushan 316022,Zhejiang,China;School of Petrochemical Engineering&Environment,Zhejiang Ocean University,Zhoushan 316022,Zhejiang,China)
出处
《低碳化学与化工》
CAS
北大核心
2023年第3期49-55,共7页
Low-Carbon Chemistry and Chemical Engineering
基金
国家自然科学基金青年基金(22202180)。
