Degaga Gemechis D, Trought Mikhail, Nemsak Slavomir, Crumlin Ethan J, Seel Max, Pandey Ravindra, Perrine Kathryn A
Department of Physics, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931-1295, USA.
Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931-1295, USA.
J Chem Phys. 2020 Feb 7;152(5):054717. doi: 10.1063/1.5138941.
Reactions on iron oxide surfaces are prevalent in various chemical processes from heterogeneous catalysts to minerals. Nitrogen (N) is known to dissociate on iron surfaces, a precursor for ammonia production in the Haber-Bosch process, where the dissociation of N is the limiting step in the reaction under equilibrium conditions. However, little is known about N adsorption on other iron-based materials, such as iron oxide surfaces that are ubiquitous in soils, steel pipelines, and other industrial materials. An atomistic description is reported for the binding of N on the FeO(001) surface using first principles calculations with ambient pressure X-ray photoelectron spectroscopy. Two primary adsorption sites are experimentally identified from N dissociation on FeO(001). The electronic signatures associated with the valence band region unambiguously show how the electronic structure of magnetite transforms near ambient pressures due to the binding of atomic nitrogen to different surface sites. Overall, the experimental and theoretical results of our study bridge the gap between ultra-high vacuum studies and reaction conditions to provide insight into other nitrogen-based chemistry on iron oxide surfaces that impact the agriculture and energy industries.
从多相催化剂到矿物质，氧化铁表面的反应在各种化学过程中都很普遍。已知氮（N）会在铁表面解离，这是哈伯-博施法中氨生产的前体，在平衡条件下，N的解离是该反应的限速步骤。然而，对于N在其他铁基材料上的吸附情况却知之甚少，比如在土壤、钢铁管道和其他工业材料中普遍存在的氧化铁表面。本文利用常压X射线光电子能谱的第一性原理计算，报道了N在FeO(001)表面结合的原子描述。通过N在FeO(001)上的解离，实验确定了两个主要吸附位点。与价带区域相关的电子特征明确显示，由于原子氮与不同表面位点的结合，磁铁矿的电子结构在接近常压时如何转变。总的来说，我们研究的实验和理论结果弥合了超高真空研究与反应条件之间的差距，为氧化铁表面其他影响农业和能源行业的氮基化学提供了深入见解。
