生物油水相催化蒸汽重整制氢催化剂氧缺陷效应的调控及其机理研究

Hydrogen production via steam reforming of bio-oil aqueous-phase (SRBA) could take full advantage of biomass renewable energy and is significant for establishing energy saving and environment friendly society. In this project, the construction of high-performance catalyst with oxygen defect effect for hydrogen production via SRBA has been put forward based on both the bio-oil characteristics and the key scientific problems of sintering and coking of Ni-based catalysts. The project proposes to remodel the porous structure of attapulgite-based zeolite-type support, create the surface Si/Al vacancies and realize the selective loading of Ni-Zr active component in Si/Al vacancies. The applicant used in-situ analysis techniques combined with XPS、TPO/TPH/TPD-MS and GC/MS instrument analytical techniques to study the capacity of active sites (such as terrace, kink, edge and metal-support interface) for breaking C-C, C-O and C-H bonds of bio-oil, to exhibit the influence of oxygen defect effect on the concentration and space-time distribution of carbon- and oxygen-contained intermediate species formed on the catalyst surface, to reveal the effect of oxygen defect effect on synergistic inhibition mechanism for sintering and carbon deposition. In addition, the applicant established the mathematic model of heat transfer and mass transfer in the interior of catalyst particle to illuminate the effect of active sites and porous structure on heat transfer and mass transfer. Furthermore, the applicant constructed the reaction kinetics model to master the effect of oxygen defect effect in catalyst on the rule of hydrogen production via SRBA. This program can supply the theoretical foundation for hydrogen production from SRBA.

生物油水相蒸汽重整制氢可以充分利用生物质能源，对建立能源节约与环境友好型社会具有重要意义。本项目针对生物油结构特性及催化剂烧结和积炭关键科学问题，提出构建具有氧缺陷效应、适合于生物油制氢催化剂。通过对凹凸棒石基沸石型载体孔道结构重塑、构建表面Si/Al空穴、实现Ni-Zr活性组分在空穴内选择性负载。采用原位分析并结合XPS、TPO/TPH/TPD-MS、GC/MS等仪器分析技术，研究台阶、拐点、边界及金属-载体界面等催化活性位点对生物油分子C-C、C-O及C-H等键的断裂行为，明晰氧缺陷效应对催化剂表面生成涉碳、涉氧中间物种浓度及时空分布的影响，揭示氧缺陷效应对催化剂烧结和积炭协同抑制机理；构建催化剂颗粒内部传热传质模型，研究催化活性中心、孔道结构对传热传质的影响；建立生物油水相蒸汽重整制氢反应动力学模型，掌握催化剂氧缺陷效应催化生物油制氢规律。本项目可为生物油制氢提供基础数据和理论依据。

针对生物油结构特性及催化剂烧结和积炭关键科学问题，选用凹凸棒石（ATP）和海泡石（SEP）作为载体原料，Ni、Co、Cu等为活性组分，制备高性能催化剂：Ni-6Ca/ATP-hs、Ni0.5Fe0.5Mn/ATP、NiFe/MA-E、10Ce-Ni/ATP、Ni-TiS/ATP、Cu-Zr/AZ（AZ为凹凸棒石基沸石）、含有Co-Al尖晶石15Co/SEP、页硅酸盐型Co/SEP-NaOH等。采用多种表征技术对催化剂进行结构分析，发现ATP和SEP具有优良的水热稳定性、丰富的微纳米多孔性以及灵活的结构可塑性；催化剂形成的特定表界面位点、微观结构、Ni-Fe合金、氧缺陷等有效地增强了金属与载体/助剂原子间电子相互作用、活性金属分散度，优化了表面酸性位点分布。. 其中，Ni-6Ca/ATP-hs催化剂具有丰富界面位点、均匀分布Ni金属颗粒在甘油蒸汽重整（GSR）过程表现出最高的转化率（86.77%）和H2氢产率（76.17%）；Ni0.5Fe0.5Mn/ATP催化剂具有最高Ni0/Ni2+比例和最优化的Ni、Fe和Mn组分之间电子协同作用，在催化蒸汽重整甲苯制氢反应中，实现了最高的甲苯转化率（99.2%）和H2产率（80.1%）；NiFe/MA-E（E表示ATP采用EDTA预处理）形成了Ni-Fe合金、具有最高的金属分散度和表面Ni0含量，在甘油水相重整制氢反应中表现出了最高的甘油向气体产物转化率（54.4%）和H2选择性（84.6%）；含有丰富Niδ--OV-Ti3+界面位点的Ni-TiS/ATP催化剂，在乙酸蒸汽重整制氢实验，表现出了93.4%的碳转化率和77.6%的氢产率；以ATP基沸石为载体制备的1Cu1Zr/AZ催化剂最高的活性金属表面积和独特的Cu0/Cu+-ZrOxHy界面位点，在甲醇蒸汽重整制氢中氢气产率达到655.1mmol/gcat/h。. 同时，对反应后的催化剂进行系列XRD、Raman、TG-DTG、TPO-MS和HRTEM-EDS表征分析，发现上述催化剂都具有优异的抗烧结和结焦性能，在长期的稳定测试活性基本保持不变。通过上述研究，初步掌握了生物油水相催化蒸汽重整制氢催化剂调控及反应规律，为进一步深化研究提供了基础数据和技术基础。