TiO2‐supported Pd‐Sb bimetallic catalysts were prepared and evaluated for the direct synthesis of H2O2 at ambient pressure.The addition of Sb to Pd significantly enhanced catalytic performance,and a Pd50Sb catalyst ...TiO2‐supported Pd‐Sb bimetallic catalysts were prepared and evaluated for the direct synthesis of H2O2 at ambient pressure.The addition of Sb to Pd significantly enhanced catalytic performance,and a Pd50Sb catalyst showed the greatest selectivity of up to 73%.Sb promoted the dispersion of Pd on TiO2,as evidenced by transmission electron microscopy and X‐ray diffraction.X‐ray photoelectron spectroscopy indicated that the oxidation of Pd was suppressed by Sb.In addition,Sb2O3 layers were formed and partially wrapped the surfaces of Pd catalysts,thus suppressing the activation of H2 and subsequent hydrogenation of H2O2.In situ diffuse reflection infrared Fourier transform spectroscopy for CO adsorption suggested that Sb homogenously located on the surface of Pd‐Sb catalysts and isolated contiguous Pd sites,resulting in the rise of the ratio of Pd monomer sites that are favorable for H2O2 formation.As a result,the Sb modified Pd surfaces significantly enhanced the non‐dissociative activation of O2 and H2O2 selectivity.展开更多
Molecular iodine was first utilized for direct oxidation of a-isophorone （α-IP） to ketoisophorone （KIP） with molecule oxygen at room temperature and the effects of amount of iodine, solvents and reaction time wer...Molecular iodine was first utilized for direct oxidation of a-isophorone （α-IP） to ketoisophorone （KIP） with molecule oxygen at room temperature and the effects of amount of iodine, solvents and reaction time were investigated extensively. The optimized result shows that 70.2% conversion of a-isophorone and 82.6% selectivity of ketoisophorone are obtained with 15% iodine （molar fraction） in acetonitrile under photoirradiation for 5 h. Moreover, the possible mechanism is proposed.展开更多
基金supported by the National Natural Science Foundation of China(91534127,U1463205)the Innovation Scientists and Technicians Troop Construction Projects of Henan Provincethe Chinese Education Ministry 111 Project(B08021)~~
文摘TiO2‐supported Pd‐Sb bimetallic catalysts were prepared and evaluated for the direct synthesis of H2O2 at ambient pressure.The addition of Sb to Pd significantly enhanced catalytic performance,and a Pd50Sb catalyst showed the greatest selectivity of up to 73%.Sb promoted the dispersion of Pd on TiO2,as evidenced by transmission electron microscopy and X‐ray diffraction.X‐ray photoelectron spectroscopy indicated that the oxidation of Pd was suppressed by Sb.In addition,Sb2O3 layers were formed and partially wrapped the surfaces of Pd catalysts,thus suppressing the activation of H2 and subsequent hydrogenation of H2O2.In situ diffuse reflection infrared Fourier transform spectroscopy for CO adsorption suggested that Sb homogenously located on the surface of Pd‐Sb catalysts and isolated contiguous Pd sites,resulting in the rise of the ratio of Pd monomer sites that are favorable for H2O2 formation.As a result,the Sb modified Pd surfaces significantly enhanced the non‐dissociative activation of O2 and H2O2 selectivity.
基金Project(21071152) supported by the National Natural Science Foundation of China
文摘Molecular iodine was first utilized for direct oxidation of a-isophorone （α-IP） to ketoisophorone （KIP） with molecule oxygen at room temperature and the effects of amount of iodine, solvents and reaction time were investigated extensively. The optimized result shows that 70.2% conversion of a-isophorone and 82.6% selectivity of ketoisophorone are obtained with 15% iodine （molar fraction） in acetonitrile under photoirradiation for 5 h. Moreover, the possible mechanism is proposed.
