Elucidation of mechanistic and kinetic aspects of water-gas shift reaction on supported Pt and Au catalysts via transient isotopic techniques
Elucidation of mechanistic and kinetic aspects of water-gas shift reaction on supported Pt and Au catalysts via transient isotopic techniques
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DOI：
10.1039/9781782626855-00175
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发表时间：
2016-01-01
期刊：
影响因子：
--
通讯作者：
Efstathiou, Angelos M.
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文献类型：
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作者：
Efstathiou, Angelos M.
随着人们对氢燃料电池应用的兴趣日益浓厚，需要具有高活性的新型和强大的水气转换（WGS）工业催化剂，最好是在低温（T < 250℃）下。在可还原性金属氧化物上负载的铂和金在这类应用中显得非常有前途。为了实现这一目标，有必要深入研究潜在催化体系的实际机制和微动力学，并需要获得活性吸附相的部位反应活性和化学成分（质量和数量）之间的内在相关性。使用原位动力学与光谱测量（operando方法）满足这些要求。稳态同位素瞬态动力学分析（SSITKA）在operando模式下与其他瞬态同位素实验相结合，可以灵敏地探测活性反应中间体的化学性质和表面组成。竞争机制（“氧化还原”和“与-OH基团结合再生”）也可以筛选，动力学参数（如速率常数）可以通过气体和吸附物质的瞬态同位素响应的先进微动力学建模获得。本文以DFT计算和实验研究为基础，介绍了WGS在负载型Pt（或Au）金属催化剂上的反应机理，以及SSITKA-operando （ftir -质谱）方法的应用，重点介绍了其优点和局限性。
With growing interest in hydrogen fuel cell applications, novel and robust water-gas shift (WGS) industrial catalysts are required with high activity, preferably at low-temperatures (T < 250 degrees C). Supported Pt and Au on reducible metal oxides appear very promising candidates for such applications. Towards this goal, the need for in-depth investigations of the actual mechanism(s) and micro-kinetics of potential catalytic systems and the need to obtain intrinsic correlations between site reactivity and chemical composition (quality and quantity) of the active adsorbed phase are imperative. The use of in situ kinetics coupled with spectroscopic measurements (operando methodology) fulfils these requirements. Steady state isotopic transient kinetic analysis (SSITKA) used in the operando mode coupled with other transient isotopic experiments can sensitively probe the chemical nature and surface composition of the active reaction intermediates. Rival mechanisms ("redox'' versus `` associative with -OH group regeneration'') can also be screened and kinetic parameters (e. g. rate constants) can be obtained through advanced micro-kinetic modelling of the transient isotopic responses of both gaseous and adsorbed species. The mechanisms of the WGS reaction on supported Pt (or Au) metal catalysts on the basis of recent DFT computations and experimental investigations, and the application of SSITKA-operando (FTIR-Mass Spectroscopy) methodology with a focus on its advantages and limitations are presented through several case studies.