The ternary systems AlGaPd and GaSbPd. Search for new catalytic materials

 

Chem. Met. Alloys 11 (2018) 6-13

 

Oksana MatselkO, Ulrich Burkhardt, Yuri Grin, Roman GLADYSHEVSKII

 

The phase relations in the Pd-rich region (≥ 50 at.% Pd) of the ternary systems AlGaPd at 600C and GaSbPd at 500C have been investigated by means of X-ray powder diffraction and EDX analysis. Four continuous substitutional solid solutions were found in the AlGaPd system: Al1-xGaxPd (FeSi-type structure, space group P213, Pearson symbol cP8), (Al1-xGax)3Pd5 (Rh5Ge3-type structure, space group Pbam, Pearson symbol oP16), Al1-xGaxPd2 (Co2Si-type structure, space group Pnma, Pearson symbol oP12), (Al1-xGax)2Pd5 (Pd5Ga2-type structure, space group Pnma, Pearson symbol oP28). In the Pd-rich part of the GaSbPd system, three new ternary phases were revealed: Ga1-xSbxPd2 (Fe2P-type structure, space group P‑62m, Pearson symbol hP9) and two tetragonal phases with approximate compositions close to Ga0.5Sb0.5Pd3, one of which crystallizes with Pt3Ga-type structure (space group P4/mbm, Pearson symbol tP16). The existence of the previously reported phase Ga4.5Sb4.5Pd25 was confirmed. The isothermal sections were constructed for the Pd-rich regions of both systems. The catalytic properties of the sample Ga28.3Sb5Pd66.7 were investigated for semi-hydrogenation of acetylene.

 

 

Isothermal sections of the phase diagrams of the systems AlGaPd at 600C and ≥ 50 at.% Pd and GaSbPd at 500C and ≥ 50 at.% Pd.

 

Keywords

Aluminum / Gallium / Antimony / Palladium / Isothermal section / Phase diagram / Semi-hydrogenation of acetylene