Synthesis gas production by dry reforming of methane over Neodymium-modified hydrotalcite-derived nickel catalysts

Y Neodymium-modified hydrotalcite-derived nickel catalysts (NixNdMgAlO) by adjusting the Nd content (x) at a range of 2.5-10% were synthesized via co-precipitation method. The catalytic properties of these catalysts were evaluated in the reaction of dry reforming of methane (DRM) at 750 degrees C. The initial CH4 conversion decreased with the order of Ni7.5NdMgAlO > Ni5NdMgAlO > NiMgAlO > Ni2.5NdMgAlO > Ni10NdMgAlO. The Ni7.5NdMgAlO catalyst with a compromised proportion of Nd at 7.5% had the smallest nickel crystallite size (8.1 nm), highest metal dispersion (11.8%), the highest exposed active sites on the surface (6.3 m(2)/g) as well as the relatively intimate interaction between small Ni2+ species and the support. Moreover, Ni7.5NdMgAlO with the largest amount of CO2 desorption (736.6 mu mol/g-cat) effectively oxidized the coke on the catalyst surface, and manifested the excellent coke resistance (2.4%) in addition to the highest CH4 and CO2 conversion in the DRM reaction. In addition, the optimal addition (7.5%) of Nd to NiMgAlO resulted in a lowering of the activation energy of CO2 by 15%. At excessive Nd content, Ni10NdMgAlO exhibited larger nickel crystallite size (10.5 nm) and was subject to severe accumulation of encapsulating carbon leading to pronounced deactivation.

Automated summary

Y Neodymium-modified hydrotalcite-derived nickel catalysts with different Nd contents showed varied catalytic properties in the dry reforming of methane reaction, with Ni7.5NdMgAlO catalyst exhibiting the best performance. Proper doping of neodymium can increase the exposure of active sites on the catalyst surface, effectively inhibit coke formation, and improve coke resistance.