Ordering in mechanically alloyed Ni(Ga) and Ni(Ga, C) solid solutions during heating

Layered Double Hydroxide-Derived Intermetallic Ni3GaC0.25 Catalysts for Dry Reforming of Methane

“…The lattice of the DFT-optimized Ni 3 GaC x structure expanded linearly with x and crossed the lattice expansion of 1.16% with a composition of Ni 3 GaC 0.25 (Figure a). It is noteworthy that a previous report also suggested Ni 3 GaC 0.25 as the equilibrium structure when the synthesis temperature was above 500 °C …”

“…As mentioned, the as-prepared NMG-LDH was completely reduced to the Ni 3 Ga phase during the reduction step at 600 °C for 5 h. This caused the reducing gas flow (50% H 2 in at 20 sccm) was switched to the DRM reaction feed (CH 4 /CO 2 = 1:1, total flow: 30 sccm). Then, the XRD reflections for Ni 3 Ga to shift toward lower angles within 1 h, indicating that Ni 3 Ga (structure type L1 2 ) was converted into the Ni 3 GaC x (structure type E2 1 ) phase, as carbon atoms penetrated to the octahedral interstices of the Ni 3 Ga lattice . This Ni 3 GaC x structure persisted for up to 5 h during the in situ XRD measurement, demonstrating that the carbon atoms initially generated by DRM at 600 °C on the NMG-600 catalyst formed the stable Ni 3 GaC x phase instead of polymeric carbon.…”

“…The space groups of Ni and Ni 3 Ga 1 were Fm 3̅ m and Pm 3̅ m , respectively. The structure of Ni 3 Ga 1 C x was modelled by inserting a C atom into the interstitial sites of a Ni 3 Ga 1 lattice according to the literature . The surface slabs of all the three materials consist of a (111) surface structure.…”

Intermetallic Ni3Ga1 Catalyst for Efficient Ammonia Reforming of Light Alkane

“…As shown in Figure a, the diffraction of Ni 3 Ga 1 shifted toward lower angles (from 43.6 to 43.3°) after the reaction, indicating the partial dissolution of C into the Ni 3 Ga 1 lattice . As carbon atoms penetrated the octahedral interstices of the Ni 3 Ga 1 , the lattice parameter increased from 0.3587 to around 0.362 nm according to Portnoi et al Consequently, the diffraction peak was shifted to lower 2θ, and all of the peaks in the PDF of used Ni 3 Ga 1 (see Figure b) slightly shifted toward higher R distance after the reaction. Noteworthily, the PDF of the fresh Ni 3 Ga 1 sample fits well with the Ni 3 Ga 1 IMC (Figure S12).…”

“…The Ni 3 Ga 1 IMC catalyst after the ethane AmmoReform has been extensively characterized by ex situ XRD and X-ray atomic pair distribution function (PDF) to identify the structural transformation during the reaction process. As shown in Figure a, the diffraction of Ni 3 Ga 1 shifted toward lower angles (from 43.6 to 43.3°) after the reaction, indicating the partial dissolution of C into the Ni 3 Ga 1 lattice . As carbon atoms penetrated the octahedral interstices of the Ni 3 Ga 1 , the lattice parameter increased from 0.3587 to around 0.362 nm according to Portnoi et al Consequently, the diffraction peak was shifted to lower 2θ, and all of the peaks in the PDF of used Ni 3 Ga 1 (see Figure b) slightly shifted toward higher R distance after the reaction.…”