通过CeZr-BTC和CeNi-BTC双金属MOFs材料为前驱体制备了多孔CeNiOx和CeZrOx复合金属氧化物，并考察了对Pd组分的分散热稳定性及天然气燃料汽车（NGVs）三效催化性能改善的构效关系。试验结果表明，制备的负载型1%Pd/CeNiOx和1%Pd/CeZrOx催化剂上Pd组分分散度可分别达到约46.3%和39.9%，经800 ℃和8 h空气气氛下老化后Pd物种粒子大小分别约为5.7 nm和7.3 nm，仍表现出较好的分散粒度和储氧性能。相对地，Pd/CeNiOx催化剂上Pd物种粒子稳定性更佳，催化剂的储氧量也更高，老化后的模拟NGVs尾气三效净化催化低温活性更佳，尤其是NO和CH4催化转化性能更优，CO，NO和CH4的转化温度T50分别可达120，206，370 ℃，T90别可达180，330，480 ℃，但CH4的转化温度仍偏高。通过具有丰富孔道结构的MOFs材料来衍生制备复合金属氧化物载体，可以适度改善Pd组分的分散热稳定性，并提供更多的可吸附位点和氧空位，从而改善NGVs三效催化性能。
The porous CeNiOx and CeZrOx composite metal oxides were prepared by using CeZr-BTC and CeNi-BTC bimetallic MOFs materials as precursor and the structureactivity relationship of improving the thermal stability of Pd component dispersion and the three-way catalytic performance of natural gas vehicles(NGVs) was investigated. The experimental results showed that the dispersions of Pd components on the prepared supported 1%Pd/CeNiOx and 1%Pd/CeZrOx catalysts reached about 46.3% and 39.9% respectively. The particle sizes of Pd species were about 5.7 nm and 7.3 nm and the catalysts still showed the better disperse particle sizse and oxygen-carrying properties after the aging of 800 ℃ and 8 h. Relatively, Pd particles on Pd/CeNiOx catalyst had the better stability and higher oxygen storage, and after aging the three-way purification of simulated NGVs exhaust had the better lowtemperature catalytic activity, especially for NO and CH4. The respective conversion temperature of CO, NO and CH4 conversion could reach 120 ℃, 206 ℃ and 370 ℃ for T50 and 180 ℃, 330 ℃ and 480 ℃ for T90, and the conversion temperature of CH4 was still too high. Accordingly, the preparation of composite metal oxide carrier derived from MOFs material with pore-rich structure could moderately improve the thermal stability of Pd component dispersion and provide more adsorption sites and oxygen vacancies and finally improve the threeway catalytic performance of NGVs exhaust.
