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
采用自制的阳离子淀粉絮凝剂,以多通道漩涡反应器(MIVM)为连续混凝器,通过实验考察了絮凝剂流量、水流量、盐流量、染料流量和酸流量对活性红SE染料废水絮凝效果的影响。实验结果表明:MIVM四股进入物料及流速分别为:絮凝剂浓度5 g/L,流...采用自制的阳离子淀粉絮凝剂,以多通道漩涡反应器(MIVM)为连续混凝器,通过实验考察了絮凝剂流量、水流量、盐流量、染料流量和酸流量对活性红SE染料废水絮凝效果的影响。实验结果表明:MIVM四股进入物料及流速分别为:絮凝剂浓度5 g/L,流速50 m L/h;染料浓度0.2 g/L,流速750 m L/h;稀盐酸浓度0.055 g/L,流速100 m L/h;自来水流速250 m L/h,染料色度去除可达99%。在最佳流速下,通过在线连续取样分析表明:装置对染料絮凝具有极好的重复性和稳定性。连续絮凝放大实验结果显示,物料流速放大30倍,染料色度去除率保持稳定,表明MIVM具有很好的絮凝放大稳定性。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.
文摘采用自制的阳离子淀粉絮凝剂,以多通道漩涡反应器(MIVM)为连续混凝器,通过实验考察了絮凝剂流量、水流量、盐流量、染料流量和酸流量对活性红SE染料废水絮凝效果的影响。实验结果表明:MIVM四股进入物料及流速分别为:絮凝剂浓度5 g/L,流速50 m L/h;染料浓度0.2 g/L,流速750 m L/h;稀盐酸浓度0.055 g/L,流速100 m L/h;自来水流速250 m L/h,染料色度去除可达99%。在最佳流速下,通过在线连续取样分析表明:装置对染料絮凝具有极好的重复性和稳定性。连续絮凝放大实验结果显示,物料流速放大30倍,染料色度去除率保持稳定,表明MIVM具有很好的絮凝放大稳定性。
