Synthesis of methanol over highly dispersed Cu-Fe based catalysts derived from layered double hydroxides

In this paper, catalysts with different aluminum contents were prepared by a co-precipitation method using LDHs (layered double hydroxides) as the precursors through the adjustment of Cu2+ : Fe2+, and the catalysts were named LDO catalysts. The effect of aluminum on CO2 hydrogenation to methanol was investigated by evaluating the characterization. With the addition of Al, Ar physisorption results showed an increase in BET-specific surface area, TEM demonstrated a decrease in catalyst particle diameter, XRD showed that Cu and Fe existed in the catalyst mainly in the form of CuFe2O4 and CuO, XPS demonstrated a decrease in electron cloud density and an increase in base sites and oxygen vacancies, and CO2-TPD and H-2-TPD results indicated that Al promoted the dissociation and adsorption of CO2 and H-2. When the reaction temperature was 230 degrees C, the pressure was 4 MPa, H-2/CO2 = 2.5 and the space velocity was 2000 ml (h g(cat))(-1), the best conversion (14.87%) and the highest methanol selectivity (39.53%) of the catalyst were obtained at 30% aluminum content.