CAJ | 학술논문

采用并流共沉淀方法制备了一系列不同铬含量的Cu/ZrO2/CNTs-NH2催化剂,在固定床反应器上考察铬对催化剂催化 CO2加氢合成甲醇反应性能的影响.当铬含量为1%(w),反应温度为260°C,压力为3.0 MPa,原料气组成为V(H2)：V(CO2)：V(N2)=69：23：8,空速为3600 mL?h-1?g-1时,催化剂的促进效果最显著,甲醇收率达7.78%.氮吸附、粉末X射线衍射(XRD)、氢气程序升温脱附(H2-TPR)、X射线光电子能谱(XPS)、二氧化碳程序升温脱附(CO2-TPD)、差热分析(DTA)以及扫描电子显微镜(SEM)等表征结果表明,随着铬含量的增加,铜颗粒的粒径减小,催化剂的比表面积增大.铬的加入一方面提高了铜的分散性,抑制了ZrO2的相变和活性组分的烧结；另一方面提高了CO2的吸附量并促进CO2由弱吸附向强吸附转化,从而提高甲醇的收率；但是当铬含量大于1%时,催化剂表面Cu、Zr的总含量明显下降,降低了CO2的吸附量并且形成了超强CO2吸附物种,抑制了CO2及其中间产物的转化,从而降低了甲醇收率.
채용병류공침정방법제비료일계렬불동락함량적Cu/ZrO2/CNTs-NH2최화제,재고정상반응기상고찰락대최화제최화 CO2가경합성갑순반응성능적영향.당락함량위1%(w),반응온도위260°C,압력위3.0 MPa,원료기조성위V(H2)：V(CO2)：V(N2)=69：23：8,공속위3600 mL?h-1?g-1시,최화제적촉진효과최현저,갑순수솔체7.78%.담흡부、분말X사선연사(XRD)、경기정서승온탈부(H2-TPR)、X사선광전자능보(XPS)、이양화탄정서승온탈부(CO2-TPD)、차열분석(DTA)이급소묘전자현미경(SEM)등표정결과표명,수착락함량적증가,동과립적립경감소,최화제적비표면적증대.락적가입일방면제고료동적분산성,억제료ZrO2적상변화활성조분적소결；령일방면제고료CO2적흡부량병촉진CO2유약흡부향강흡부전화,종이제고갑순적수솔；단시당락함량대우1%시,최화제표면Cu、Zr적총함량명현하강,강저료CO2적흡부량병차형성료초강CO2흡부물충,억제료CO2급기중간산물적전화,종이강저료갑순수솔.
A series of Cu/ZrO2/CNTs-NH2 catalysts with various chromium dopings were prepared using a co-precipitation method for the synthesis of methanol by the hydrogenation of CO2. The impact of the addition of chromium on the catalytic performance of the Cu/ZrO2/CNTs-NH2 catalyst was investigated in a fixed-bed plug flow reactor. When the chromium loading was set to 1% of the total amount of Cu2+and Zr4+, the methanol yield increased to a maximum of 7.78% (reaction conditions: 3.0 MPa, 260 °C, V(H2):V(CO2):V(N2)=69:23:8 and gaseous hourly space velocity (GHSV)=3600 mL?h-1?g-1). The catalysts were characterized by N2 physisorption, X-ray diffraction (XRD), temperature-programmed desorption of H2 (H2-TPD), X-ray photoelectron spectroscopy (XPS), temperature- programmed desorption of CO2 (CO2- TPD), differential thermal analysis (DTA), and scanning electron microscopy (SEM). The results of these analyses indicated that the introduction of chromium reduced the size of the Cu nanoparticles, enhanced the dispersion of the Cu species, inhibited the phasetransformation and sintering of ZrO2, increased the specific surface area, enhanced the amount of CO2 adsorbed, and promoted the conversion of weakly adsorbed CO2 species to strongly adsorbed CO2 species. Taken together, these factors lead to a high methanol yield. However, when the chromium loading was greater than 1%, the amount Cu and Zr on the surface, as well as the size of the Cu nanoparticle reduced considerably, which led to a significant reduction in the adsorption of CO2 species. This effect also facilitated the formation of strongly adsorbed CO2 species, leading to lower methanol yields.