钒钛基SCR催化剂密度泛函理论计算研究进展

摘要

从基本结构模型和相关化学反应两大方面综述了选择性催化还原（ SCR）脱硝催化剂密度泛函理论（ DFT）计算的研究现状，对理论模型构建方法、基于理论计算的催化剂表面特性以及相关化学反应机理进行了总结。负载型周期性结构模型更接近真实催化剂表面结构，其计算结果与实验的可对照性更强。钒氧化物（ VOx ）在TiO2（001）面上负载时体系结构最稳定，以类似表面重构的结构或延伸TiO2晶体结构的形式与TiO2载体键合。V多以四面体配位形式存在，V-O-V和V-O-Ti是重要的活性位点。NH2 NO是SCR反应过程中的重要中间体，存在多种生成路径。SCR催化剂表面零价汞（ Hg0）氧化生成HgCI2的反应遵循Langmuir-HinsheIwood机理。%A review on density functionaI theory( DFT)study of V2 O5/TiO2 based seIective cataIytic re-duction( SCR)cataIyst was presented. Construction of the theoreticaI modeI,surface property of the cata-Iyst and mechanisms of SCR and mercury oxidation reaction were reviewed. Periodic modeI is more appro-priate to represent the cataIyst surface. Vanadium oxides(VOx)preferentiaIIy anchor to the(001)facet of anatase,in the“ad-moIecuIe”form or with an anatase-Iike structure. VOx is usuaIIy tetrahedraIIy coor-dinated and the bridging oxygens in V-O-V and V-O-Ti are cruciaI active sites. NH2 NO is the key inter-mediate in SCR reaction,with muItipIe paths to generate. Oxidation of Hg to HgCI2 on SCR cataIyst sur-face foIIows a Langmuir-HinsheIwood mechanism.