Abstract
For the development of effective catalysts for the autothermal reforming of methane, the NiPd catalysts were synthesized based on modified aluminum oxide and their physicochemical properties were studied using X-ray diffraction analysis, low-temperature nitrogen adsorption, transmission electron microscopy, and temperature-programmed reduction with hydrogen. It was found that the variation of modifying components (CeO2, ZrO2, La2O3, Ce0.5Zr0.5O2, and La2O3/Ce0.5Zr0.5O2) and their concentrations (10–30 wt %) makes it possible to regulate the particle size of NiO, the composition of a Ni-containing phase (NiO, La2NiO4, NiAl2O4, or Ni-La-Al-O) and the redox properties of nickel ions. It was shown that the average particle size of NiO increased from 6.7 to 17.5 nm in the following order of supports: La2O3/Al2O3 < La2O3/Ce0.5Zr0.5O2/Al2O3 < Al2O3 < Ce0.5Zr0.5O2/Al2O3 < CeO2/Al2O3 < ZrO2/Al2O3. On the introduction of the modifying oxides CeO2 and ZrO2 into aluminum oxide, the fraction of nickel in the composition of NiAl2O4 decreased and, therefore, the fraction of difficult-to-reduce Ni2+ decreased. The addition of La2O3 and La2O3/Ce0.5Zr0.5O2 strengthened the interaction of nickel cations with the support up to the formation of Ni-La-Al-O and La2NiO4 phases and increased the fraction of difficult-to-reduce Ni2+ ions. The resulting NiPd catalysts are promising in the catalysis of the autothermal reforming of methane.
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