Applied Catalysis A: General, Vol.481, 104-115, 2014
Hydrogen production by autothermal reforming of methane: Effect of promoters (Pt, Pd, Re, Mo, Sn) on the performance of Ni/La2O3 catalysts
We developed bimetallic catalysts Ni-Me/La2O3 (Me = Pt, Pd, Re, Mo, Sn) for hydrogen production by autothermal reforming of methane (ATR of CH4). The preparation procedure was based on the reduction of an appropriate LaNi1-xMexO3 (x = 0.01-0.05) perovskite precursor obtained by the citrate sol-gel method. We investigated the effects of promoter type and molar ratio Me/Ni (Me = Pt, Pd, Re, Mo, Sn; Me/Ni = 0.01-0.05) on the structural, reducing and catalytic properties of Ni-Me/La2O3 samples in the ATR of CH4 and systematically studied the genesis of catalysts by means of X-ray diffraction, thermogravimetric and differential thermal analysis, Ar adsorption, H-2 temperature-programmed reduction, high-resolution transmission electron microscopy with energy-dispersive X-ray analysis, and X-ray photoelectron spectroscopy techniques. The genesis of the active phase is shown to be strongly affected by the promoter type. The Pt, Re, Mo or Sn promoters in contrast to Pd impede the destruction of LaNiO3 structure and formation of Ni-0 phase. The catalytic performance of Ni-Me/La2O3 samples in the ATR of CH4 can be regulated by the type and content of the promoter. At low reaction temperatures (700-800 degrees C) and at the molar ratio Me/Ni = 0.01 the conversion of methane and product (H-2, CO) yields increases in the following order of promoters: Pt < Sn < Mo < Re < Pd, which correlates with the increase of reducibility of Ni species as a result of promoter addition. At 850 degrees C the LaNi0.99Pd0.01 O-3 catalyst provided the yields of similar to 41% H-2 and similar to 57% CO at CH4 conversion similar to 100% during a stability test that lasted 24 h. (C) 2014 Elsevier B.V. All rights reserved.