Direct synthesis of methyl formate from syngas on Cu–Mn mixed oxide catalyst

•Cu–Mn and CaO–ZrO2 are a novel catalyst system to synthesize MF from syngas.•The influences of Cu/Mn ratio on the direct synthesis of MF are investigated.•The highest MF selectivity of 83.6% is observed on Cu0.5Mn catalyst.•CuO and Cu1.5Mn1.5O4 are the main active phases for the direct synthesis of MF.

Cu–Mn mixed oxides with different Cu/Mn molar ratios were prepared by ammonia complexation method, and their catalytic performances have been evaluated for the direct synthesis of methyl formate (MF) from syngas. The catalysts were characterized by N2 adsorption-desorption isotherm, XRD, TEM, SEM, FT-IR, XPS and TPR measurements. Results revel that incomplete spinel of Cu1.5Mn1.5O4, CuO and amorphous Mn species are formed in all Cu–Mn catalysts. The interaction between Cu and Mn in Cu–Mn catalyst delays the reduction of samples compared with pure Cu oxide. For the direct synthesis of MF from syngas, Cu–Mn catalysts showed higher catalytic activities and MF selectivities than pure Cu or Mn oxides. CO conversion increases and MF selectivity decreases with the rise of Cu/Mn ratios in catalysts, which could be attributed to the phase compositions, specific surface areas, and the reducibility of the catalysts.

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