Methane Dry Reforming over Ni/NiO Supported on Ce-, Zr-, and Al-Modified Y2O3 for Hydrogen Production
Zijian Chen, Lei Mao, Xiuzhong Fang, Xianglan Xu, Junwei Xu, Xiang Wang
Abstract
In this work, Ce, Zr, and Al are used to promote Y2O3 as supports for Ni/NiO, with the expectation to obtain more efficient catalysts for DRM reaction. XRD and Raman results have testified that all the three cations have been doped into the lattice of Y2O3 to form a solid solution structure, thus obtaining supports with decreased crystallinity and improved surface areas. As a result, all the modified catalysts display evidently improved reaction performance. The Ni–support interaction of the modified catalysts is enhanced in comparison with the unmodified catalyst, thus having improved Ni dispersion. Moreover, the modified catalysts have improved alkalinity, which is beneficial to activate CO2 and enhance the activity. In addition, it is found that all the modified catalysts possess a richer amount of surface active oxygen species (O2δ− and O2−), which is critical to eliminate carbon depositions. It is believed that the interaction of these factors is responsible for the enhanced DRM performance of the modified catalysts. In situ DRIFTS results have confirmed that the addition of the secondary metals can improve the DRM activity of the catalyst by accelerating the conversion of formate intermediate species.