Effect of manganese and potassium addition on CeO2-Al2O3 catalyst for hydrogenation of benzoic acid to benzaldehyde

A series of Mn/CeO₂-Al₂O₃ and K/CeO₂-Al₂O₃ catalysts for hydrogenation of benzoic acid to benzaldehyde were prepared to investigate the effect of Mn, K addition on CeO₂-Al₂O₃ catalyst. X-ray diffraction (XRD) and H₂-temperature-programmed reduction (H₂-TPR) results suggested that the interaction between CeO₂ and MnO_x enhanced the reducibility of catalysts and therefore benzoic acid conversion. The addition of K increased the number of basic number on the catalyst which leads to a high selectivity to benzaldehyde, but excessive addition imposed negative effects on the catalyst performance. A Mn-K/CeO₂-Al₂O₃ catalyst was developed and investigated in the reaction. The simultaneous addition of Mn and K enhanced not only the catalytic activity but also the capacity to resist the coke formation over catalyst.