Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Co3Mo3N”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

Materials Data on Co3Mo3N by Materials Project

Co3Mo3N crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Mo is bonded in a 2-coordinate geometry to six Co and two equivalent N atoms. There are a spread of Mo–Co bond distances ranging from 2.67–2.73 Å. Both Mo–N bond lengths are 2.13 Å. There are two inequivalent Co sites. In the first Co site, Co is bonded to six equivalent Mo and six equivalent Co atoms to form CoCo6Mo6 cuboctahedra that share edges with six equivalent NMo6 octahedra and faces with six equivalent CoCo6Mo6 cuboctahedra. All Co–Co bond lengths are 2.37 Å. In the second Co site, Co is bonded in a 12-coordinate geometry to six equivalent Mo and six Co atoms. All Co–Co bond lengths are 2.51 Å. N is bonded to six equivalent Mo atoms to form NMo6 octahedra that share corners with six equivalent NMo6 octahedra and edges with six equivalent CoCo6Mo6 cuboctahedra. The corner-sharing octahedral tilt angles are 47°.

36 MATERIALS SCIENCE↗

Two-Step Chemical Looping Cycle for Renewable NH 3 Production Based on Non-Catalytic Co 3 Mo 3 N/Co 6 Mo 6 N Reactions

A two-step solar thermochemical looping cycle based on Co 3 Mo 3 N/Co 6 Mo 6 N reduction/nitridation reactions offers a pathway for green NH 3 production that utilizes concentrated solar irradiation, H 2 O, and air as feedstocks. The NH 3 production cycle steps both derive process heat from concentrated solar irradiation and encompass 1) the reduction of Co 3 Mo 3 N in H 2 to Co 6 Mo 6 N and NH 3 ; and 2) nitridation of Co 6 Mo 6 N to Co 3 Mo 3 N with N 2 . Co 3 Mo 3 N reduction/nitridation reactions are examined at different H 2 and/or N 2 partial pressures and temperatures. NH 3 production is quantified in situ using liquid conductivity measurements coupled with mass spectrometry (MS). Solid-state characterization is performed to identify a surface oxygen layer that necessitates the addition of H 2 during cycling to prevent surface oxidation by trace amounts of O 2 . H 2 concentrations of > 5% H 2 /Ar and temperatures >500 °C are required to reduce Co 3 Mo 3 N to Co 6 Mo 6 N and form NH 3 at 1 bar. Complete regeneration of Co 3 Mo 3 N from Co 6 Mo 6 N is achieved at conditions of 700 °C under 25–75% H 2 /N 2 . H 2 pressure-swings are observed to increase NH 3 production during Co 3 Mo 3 N reduction. In conclusion, the results represent the first comprehensive characterization of and definitive non-catalytic production of NH 3 via chemical looping with metal nitrides and provide insights for technology development.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗