Fig. 3: Catalyst characterization.
From: Cobalt-based catalyst for ammonia synthesis under ambient conditions via transient confinement
a X-ray diffraction (XRD) patterns of fresh Co and Co(N*) after N2 pre-milling. b Evolution of Co(N*) XRD patterns during hydrogenation; the reaction conditions were as follows: 20 mL/min H2; 10 °C/min rate heating to 400 °C and then holding at 400 °C for 70 min. c, d X-ray photoelectron spectroscopy (XPS) patterns of fresh Co, Co(N*) after N2 pre-milling, used Co after reaction: c N 1s and d Co 2p. e Radial distribution function (RDF) of the Co foil, CoO, CoxN, fresh Co, Co(N*) after N2 pre-milling, and used Co. The RDFs were derived from extended x-ray-absorption fine structure (EXAFS) data. f Isotope exchange experimental results. Fresh Co (15 g) was pre-milled for 24 h in 14N2, and then 15N2 and D2 were introduced to record the reaction products. Reaction conditions were as follows: 25 °C, 1 bar, 1000 rpm, and 600 g Fe balls as the milling medium. Prior to the test, the Co catalyst was pretreated in 10% H2/Ar at 250 °C for 2 h.
