In-situ infrared spectroscopy of base metal catalysts for automotive applications

在汽车工业中，消除催化转化器中的贵金属是一个备受追捧的目标。催化转化器由涂有催化剂层的陶瓷塞组成。该插头被集成到汽车的排气系统中，用于被动地将一氧化碳、未燃烧的碳氢化合物和氮氧化物转化为毒性较小的产品，如二氧化碳、水和双原子氮。目前这一代的催化剂材料使用贵金属，如铂、钯和铑，在几百摄氏度的温度下完成还原和氧化反应。由富含地球的金属如铁、钴、铜和镁制成的催化剂的开发将大大降低催化转化器的成本。然而，贱金属催化剂广泛应用的一个主要挑战是水和长时间老化对催化剂效率的有害影响。了解水吸附/解吸和金属氢氧化物形成的机理细节对于设计更坚固的材料至关重要。此外，了解高性能催化剂材料的化学组成和晶体结构对知识产权的开发具有重要意义。为了应对这些挑战，我们将对在不同条件下制备和测试的贱金属催化剂进行红外光谱分析，并通过对所得光谱的仔细分析，确定有害或有助于催化剂材料效率的关键化学成分。此外，我们将实时观察材料老化，并使用自制的原位红外光谱实验，监测催化剂在几百摄氏度下进行反应时的反应物、产物和任何中间体。

Eliminating precious metals in catalytic converters is a highly sought-after goal in the automotive industry.Catalytic converters consist of a ceramic plug that is coated with a catalyst layer. The plug is incorporated intothe exhaust system of an automobile and is used to passively convert carbon monoxide, unburnedhydrocarbons, and nitrogen oxides into less toxic products like carbon dioxide, water, and diatomic nitrogen.The current generation of catalyst materials use precious metals like platinum, palladium, and rhodium toaccomplish the reduction and oxidation reactions at temperatures of several hundred degrees Celsius. Thedevelopment of catalysts made from earth abundant metals like iron, cobalt, copper, and magnesium wouldprovide a significant reduction in the cost of a catalytic converter. However, a major challenge to thewidespread application of base metal catalysts is the harmful effect of water and extended aging on theefficiency of the catalyst. Understanding the mechanistic details of water adsorption/desorption and theformation of metal hydroxides is critical in the design of more robust materials. Moreover, a clearunderstanding of the chemical composition and crystal structure of high performance catalyst materials isimportant in the development of intellectual property. In order to address these challenges, we will performinfrared spectroscopy on base metal catalysts that were prepared and tested under different conditions, andthrough careful analysis of the resulting spectra, identify key chemical components that either harm or help theefficiency of the catalyst material. In addition, we will watch material aging in real time and monitor reactants,products, and any intermediates as the catalysts perform reactions at several hundred degrees Celsius using ahome-built in-situ infrared spectroscopic experiment.