金属掺杂对LaFe基钙钛矿催化CO2加氢制低碳烯烃性能影响

Effects of metal doping on the catalytic performance of LaFe-based perovskites for CO2 hydrogenation to light olefins

  • 摘要: 通过溶胶-凝胶法和浸渍法制备K/LaFeBO3 (B =Cu、Zr、Al、Mn、Ni、Zn)钙钛矿催化剂,结合SEM、XRD、BET、H2-TPR、CO2-TPD、TG、XPS等表征,探究了金属掺杂对LaFe基钙钛矿催化CO2加氢制备低碳烯烃性能的影响。结果表明,Cu和Zn的加入有利于提高Fe分散度并降低还原温度,同时低温下氢的脱附增加且碱性位增多。氧空位迁移变化对催化活性和烯烃选择性有重要影响,当Cu和Zn在B位取代Fe时,氧迁移率增加明显,具有较低结合能的表面晶格氧富集,显著提高了催化活性,促进了低碳烯烃生成。

     

    Abstract: The catalytic behavior of K/LaFeBO3 (B =Cu, Zr, Al, Mn, Ni, and Zn) perovskite catalysts prepared by sol-gel and impregnation methods was investigated for CO2 hydrogenation to light olefins. The structure of various catalysts was characterized in detail by SEM, XRD, N2 adsorption-desorption, H2-TPR, CO2-TPD, TG, and XPS analysis. With the addition of Cu and Zn, the particles size decreased with high dispersion of Fe, while the exposed basic sites increased with lower hydrogen desorption temperature. The oxygen mobility in perovskites exhibited a considerable impact on catalytic activity and olefins selectivity, which considerably increased when Fe was substituted by Cu and Zn at the B site. Olefins were formed preferentially from oxygen species of the surface lattice with low binding energies (BEs). In addition, a faster diffusion rate of oxygen would lead to an enrichment of lattice oxygen species on the surface and increase the production of olefins.

     

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