原子钼催化剂配位结构的动态演变促进氢分子在浆态床加氢裂化过程中的高效活化  

Atomic coordination structural dynamic evolution of single-atom Mo catalyst for promoting H2 activation in slurry phase hydrocracking

作　　者：孙广洵 刘东源 李敏 陶舒 管泽坤 陈彦飞 刘士欢 杜青洲 国含 苑馨月 张心颖 朱后禹 刘宾 潘原 Guangxun Sun;Dongyuan Liu;Min Li;Shu Tao;Zekun Guan;Yanfei Chen;Shihuan Liu;Qingzhou Du;Han Guo;Xinyue Yuan;Xinying Zhang;Houyu Zhu;Bin Liu;Yuan Pan(State Key Laboratory of Heavy Oil Processing,China University of Petroleum(East China),Qingdao 266580,China;School of Materials Science and Engineering,China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]State Key Laboratory of Heavy Oil Processing,China University of Petroleum(East China),Qingdao 266580,China [2]School of Materials Science and Engineering,China University of Petroleum(East China),Qingdao 266580,China

出　　处：《Science Bulletin》2023年第5期503-515,M0004,共14页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation of China(22108306 and 22078362);Shandong Provincial Natural Science Foundation(ZR2021YQ15 and ZR2020QB174);PetroChina Innovation Foundation(2019D-5007-0401);Taishan Scholars Program of Shandong Province(tsqn201909065);the Fundamental Research Funds for the Central Universities(22CX07009A,19CX05001A);Postgraduate Innovation Fund of China University of Petroleum(East China)(YCX2020037).

摘　　要：开发具有高原子利用率和高转化频率的高效催化剂,用于减压渣油浆态床加氢裂化过程中H2分子的活化至关重要.本文采用“聚合-热解-原位硫化”策略,首次报道了一种高效稳定的单原子钼催化剂用于减压渣油浆态床加氢裂化反应,并发现了单原子Mo活性位点的原子配位结构动态演化机制.在VR加氢裂化过程中,与Mo配位的O原子逐渐被S原子取代,从而导致O/S交换过程.单原子钼的配位结构从反应前的Mo-O3S1演变为反应后的Mo-O1S3配位构型,有效促进了H2分子均裂活化为H自由基物种.所演变的单原子钼催化剂表现出优异的催化加氢活性和循环稳定性,其对减压渣油的单程转化率为65 wt.%,轻油收率为93 wt.%,焦炭产率仅为0.63 wt.%,按照所有金属计算的转化频率为0.35 s^(-1).理论计算表明,H2相互作用前后Mo 4d占据态的显著变化与单原子钼催化剂结构的动态演变有直接关系,并且Mo-O1S3位点较低的d带中心表明原子H扩散容易,有利于催化加氢.本文研究结果对于开发高原子经济性催化剂用于重油改质技术的工业应用具有重要意义.Development of efficient catalysts with high atomic utilization and turnover frequency(TOF)for H2activation in slurry phase hydrocracking(SPHC)is crucial for the conversion of vacuum residue(VR).Herein,for the first time,we reported a robust and stable single atoms(SAs)Mo catalyst through a polymerization-pyrolysis-in situ sulfurization strategy for activating H2in SPHC of VR.An interesting atomic coordination structural dynamic evolution of Mo active sites was discovered.During hydrocracking of VR,the O atoms that coordinated with Mo were gradually replaced by S atoms,which led to the O/S exchange process.The coordination structure of the Mo SAs changed from pre-reaction Mo-O3S1to postreaction Mo-O1S3coordination configurations,promoting the efficient homolytic cleavage activation of H2into H radical species effectively.The evolved Mo SAs catalyst exhibited robust catalytic hydrogenation activity with the per pass conversion of VR of 65 wt%,product yield of liquid oils of 93 wt%,coke content of only 0.63 wt%,TOF calculated for total metals up to 0.35 s^(-1),and good cyclic stability.Theoretical calculation reveals that the significant variation of occupied Mo 4d states before and after H2interaction has a direct bearing on the dynamic evolution of Mo SAs catalyst structure.The lower d-band center of Mo-O1S3site indicates that atomic H diffusion is easy,which is conducive to catalytic hydrogenation.The finding of this study is of great significance to the development of high atom economy catalysts for the industrial application of heavy oil upgrading technology.

关 键 词：加氢裂化 减压渣油 轻油收率 配位结构 单原子 动态演变 浆态床 原子利用率 

分 类 号：TE624[石油与天然气工程—油气加工工程]