NiSn alloy properties in Ni–Sn/γ-Al2O3 catalyst under propylene hydrogenation

Abstract Several efforts have been made to design low-cost metal-based catalysts with high performance in various biorefinery processes, making them more feasible and economically competitive. At this point, the NiSn alloys have shown significant potential. This study aims to investigate the properties of γ-Al 2 O 3 -supported Ni–Sn catalysts synthesized under conditions that allow alloy formation. First, the wet impregnation method was used to prepare the catalysts and then characterized using the techniques: N 2 physisorption, X-ray fluorescence, X-ray diffraction, H 2 temperature programmed reduction, and H 2 temperature programmed desorption. After, the catalytic test was performed through propylene hydrogenation. Characterization data revealed a decrease in the surface area of the catalysts after impregnation with Sn. The X-ray diffraction results showed a weak interaction between the active metal and the support, favoring a stronger interaction between Ni and Sn, which led to the formation of Ni 3 Sn and Ni 3 Sn 2 alloys. The presence of high Sn content also favored the formation of the NiSn alloys; however, the high tin content contributed to a decrease in the Ni dispersion on the support, increasing the Ni 0 crystallite size. The catalyst with the highest Sn concentration showed mostly Ni 3 Sn 2 alloy diffraction peaks, whereas the catalyst with the lowest Sn content showed the Ni 3 Sn alloy. The H 2 temperature programmed desorption showed that the presence of alloys possibly modified the active sites, leading to a different catalytic performance compared with Ni/γ-Al 2 O 3 . The catalysts with Ni 3 Sn alloy, as determined by catalytic tests, showed a conversion of up to 87%, better activity, and stability for 24 h compared to the catalyst with Ni 3 Sn 2 alloy.