双金属有机骨架材料衍生CuO-Cu1.5Mn1.5O4复合氧化物的丙烷催化燃烧性能

采用气相辅助的离子置换法,合成了Cu、Mn双金属有机骨架(MOF)材料,通过控制煅烧条件制备了一系列CuO-Cu_1.5Mn_1.5O₄复合氧化物,研究了不同n(Mn)/n(Cu)对丙烷催化燃烧性能的影响。结果表明:随着n(Mn)/n(Cu)提高,CuO-Cu_1.5Mn_1.5O₄催化丙烷燃烧能力增强,当n(Mn)/n(Cu)为31∶69时,催化剂对丙烷的完全燃烧温度(T₉₀)仅为309.8 ℃,催化活性远高于CuO和Mn₂O₃。表征和密度泛函理论(DFT)计算结果表明,由于Mn和Cu的相互作用,复合氧化物表面具有更高的n(Mn4+)/n(Mn3+)和n(Cu+)/n(Cu2+),从而增强了催化剂的低温还原性能。并且n(Cu+)/n(Cu2+)提高导致催化剂中氧空位浓度升高,更容易吸附活化O₂、丙烷分子,增强了催化剂的丙烷燃烧性能。

SYNTHESIS OF CuO-Cu1.5Mn1.5O4 COMPOSITE OXIDE BY USING A BIMETALLIC ORGANIC FRAMEWORK FOR CATALYTIC PROPANE TOTAL OXIDATION

In the paper, Cu and Mn bimetallic organic framework materials were prepared using the gas-assisted ion replacement method. A series of CuO-Cu_1.5Mn_1.5O₄ composite oxides were prepared through controlled calcination, and the effect of various n(Mn)/n(Cu) on the catalytic performance of propane total oxidation was studied. The results revealed that with an increase in the n(Mn)/n(Cu), CuO-Cu_1.5Mn_1.5O₄ catalysts showed enhanced propane total oxidation catalytic activities. When n(Mn)/n(Cu) was 31∶69, the complete combustion temperature (T₉₀) of propane was just 309.8 ℃, signifying that the activity was much higher than that of CuO and Mn₂O₃. The experimental and density functional theory (DFT) calculation results revealed that the synergetic effect of Mn and Cu increased the n(Mn4+)/n(Mn3+) and n(Cu+)/n(Cu2+) on the surface, which enhanced the redox ability at low-temperature. Meanwhile, the increase of n(Cu+)/n(Cu2+) led to a higher concentration of oxygen vacancies, and made it easier to adsorb and activate oxygen and propane molecules on the surface, thereby boosted the propane catalytic oxidation performance.