Synthesis of Ni5Ga3 catalyst by Hydrotalcite-like compound (HTlc) precursors for CO2 hydrogenation to methanol

A Ni5Ga3 catalyst synthesized from hydrotalcite-like compound (HTlc) precursors was examined for CO2 hydrogenation to methanol. HTlc precursors with a nickel atomic percentage of 65 % balanced with gallium were prepared by a urea hydrolysis hydrothermal method, and fully characterized. The HTlc phase in the nickel-gallium precipitant became better crystallized and the structure became more stable as the synthesis reaction temperature increased. Bimetallic alloy Ni5Ga3 was obtained by reducing the as-prepared HTlc precursors in a flow of 5 % H-2 balanced with Ar at a temperature of 700 degrees C. Ni-Ga HTlc precursor prepared at a hydrothermal temperature of 110 degrees C resulted in the formation of bimetallic alloy, Ni5Ga3, which produces smaller crystal size and a stable structure. Enhanced catalytic performance was demonstrated by an endurance test with a constant CO2 conversion and 100 % methanol selectivity at 200 degrees C, and a turnover frequency of 0.27 s(-1).