电场协同Cs掺杂Co3O4催化N2O低温高效分解

    Synergistic Effect of Electric Field on Cs Doped Co3O4 for Low-Temperature Efficient Decomposition of N2O

    • 摘要: 为解决氨内燃机复杂排气中氧化亚氮(N2O)难以低温高效去除的问题,提出了一种电场与Cs掺杂Co3O4协同催化N2O低温高效分解的新策略。采用柠檬酸络合法合成了一系列不同Cs掺杂量的Co3O4催化剂并与SiC载体耦合,发现在电场作用下N2O的分解温度显著降低。在90 000 h-1的空速下,Cs0.1–Co3O4/SiC催化剂能够在125 ℃时实现N2O完全分解。机理研究表明,Cs作为电子助剂,适量掺杂可构建Cs–Co3+/Co2+高效电子转移界面,同时提高了催化剂表面Co2+位点浓度和晶格氧的流动性,从而形成更多的OV(氧空位)–Co2+活性中心。在电场作用下,Cs的供电子效应得到进一步强化,加速了N2O分解的氧化还原循环过程,最终驱动N—O键的断裂与N2O低温高效解离。

       

      Abstract: To address the challenge of low-temperature efficient nitrous oxide (N2O) removal from the complex exhaust of ammonia-fueled internal combustion engines, a novel strategy was proposed for the low-temperature efficient catalytic decomposition of N2O through the synergistic effect of electric field on Cs-doped Co3O4. A series of Co3O4 catalysts with varying Cs doping levels were synthesized via the citrate complexation method and coupled with SiC support. It was found that the decomposition temperature of N2O was significantly reduced under the application of an electric field. The Cs0.1–Co3O4/SiC catalyst achieved complete decomposition of N2O at 125 ℃ with a space velocity of 90 000 h-1. Mechanistic studies have revealed that Cs, as an electron promoter, can construct an efficient electron transfer interface of Cs–Co3+/Co2+ when doped in moderation. It not only enhances the concentration of Co2+ sites on the catalyst surface but also improves the mobility of lattice oxygen, thereby forming more OV(oxygen vacancy)–Co2+ active centers. Under the influence of an electric field, the aforementioned electron-donating effect of Cs is further intensified, accelerating the redox cycle process of N2O decomposition and ultimately driving the breakage of N—O bonds and efficient dissociation of N2O at low temperatures.

       

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