PNNL

Abstract

Co, Ni and Zn-containing MOFs are prepared and then pyrolyzed to generate materials for ambient temperature NO adsorption. Materials containing Co are much more efficient for NO adsorption than those containing Ni and Zn; therefore, Co is identified as the active phase. The best performing material studied here achieves 100% low concentration (10ppm) NO adsorption for more than 15 h under a weight hourly space velocity (WHSV) of 120,000 ml g-1 h-1. Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), FT-IR and Raman spectroscopies, along with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are used to probe the physicochemical properties of the materials, particularly the Co active phase, and chemistries involved in NO adsorption-desorption. NO adsorbs on oxygen-covered Co nanoparticle surfaces in the form of nitrates, and desorbs as NO at higher temperatures as a result of surface nitrate decomposition. NO storage capacity decreases slowly upon repeated NO adsorption-desorption cycles, likely because of Co3O4 formation during these processes. The authors from East China University of Science and Technology acknowledge support from National Basic Research Program of China (2013CB933200), National Natural Science Foundation of China (21577035, 21577034), Commission of Science and Technology of Shanghai Municipality (15DZ1205305) and 111 Project (B08021). Aiyong Wang acknowledges the China Scholarship Council for the Joint-Training Scholarship Program with the Pacific Northwest National Laboratory (PNNL). PNNL is operated for the U.S. Department of Energy (DOE) by Battelle. FG is supported by the U.S. DOE/Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office.