Effect of Ce and Zr Addition to Ni/SiO2 Catalysts for Hydrogen Production through Ethanol Steam Reforming

Abstract

A series of Ni/Ce x Zr 1−x O 2 /SiO 2 catalysts with different Zr/Ce mass ratios were prepared by incipient wetness impregnation. Ni/SiO 2 , Ni/CeO 2 and Ni/ZrO 2 were also prepared as reference materials to compare. Catalysts' performances were tested in ethanol steam reforming for hydrogen production and characterized by XRD, H 2 -temperature programmed reduction (TPR), NH 3 -temperature programmed desorption (TPD), TEM, ICP-AES and N 2 -sorption measurements. The Ni/SiO 2 catalyst led to a higher hydrogen selectivity than Ni/CeO 2 and Ni/ZrO 2 , but it could not maintain complete ethanol conversion due to deactivation. The incorporation of Ce or Zr prior to Ni on the silica support resulted in catalysts with better performance for steam reforming, keeping complete ethanol conversion over time. When both Zr and Ce were incorporated into the catalyst, Ce x Zr 1−x O 2 solid solution was formed, as confirmed by XRD analyses. TPR results revealed stronger Ni-support interaction in the Ce x Zr 1−x O 2 -modified catalysts than in Ni/SiO 2 one, which can be attributed to an increase of the dispersion of Ni species. All of the Ni/Ce x Zr 1−x O 2 /SiO 2 catalysts exhibited good catalytic activity and stability after 8 h of time on stream at 600• C . The best catalytic performance in terms of hydrogen selectivity was achieved when the Zr/Ce mass ratio was three.

Hydrogen Production by Steam Reforming of Ethanol on Rh-Pt Catalysts: Influence of CeO2, ZrO2, and La2O3 as Supports

“…Table 1 shows the TGA results for reduced and aged catalysts. No significant differences were observed between both samples at ceria and zirconia catalysts, consistent with their basic nature [59,71,72]. The RhPt/La2O3 behavior is ascribed to the La hydrides reaction with oxygen, which is favored in the presence of active metals, as was found in the oxidation/reduction cycles of this support (Section 2.4.1) [30,73].…”

“…However, no important differences were recorded between reduced and aged samples, showing that this La hydrides decomposition on the support is the main weight loss cause. In general, results indicate that carbonaceous residues did not play an important role in determining the stability of the catalysts, confirming that basic supports may reduce the formation of carbonaceous compounds [13,36,64,72].…”

Production of Renewable Hydrogen from Glycerol Steam Reforming over Bimetallic Ni-(Cu,Co,Cr) Catalysts Supported on SBA-15 Silica

“…Today, hydrogen is mainly produced from the thermochemical conversion of fossil fuels at high pressures and temperatures, particularly by steam reforming of natural gas, which is associated with various environmental issues related to greenhouse gases. In this context, alcohols derived from biomass, like methanol [4], ethanol [3,5], or glycerol [6][7][8] may also be reformed to generate hydrogen, turning reforming into a zero net carbon emissions process. and tailored particle morphology [31].…”

Response Surface Methodology and Aspen Plus Integration for the Simulation of the Catalytic Steam Reforming of Ethanol

“…Finally, the FC was modeled as a reactor (FC) operating at 150 • C [67], with a preheating (HE4) to ensure this condition, and 80% H 2 conversion and 40% electrical efficiency were assumed in FC [68]. Aspen Plus was used to calculate the enthalpies of each stream in order to determine the energy requirements in each equipment of the system (Figure 2) per mole of ethanol inlet and per mol of H 2 produced in SRE according to Equations (22) and (23), respectively, where ∆H i is the total change of enthalpy in the equipment i (i.e., HE1, SRE, CDS, PROX, HE2, HE3, HE4, or FC); H S1i and H S2i are the total enthalpy (kJ/min) in the inflow and outflow of equipment i, respectively; F H2,outlet is the mole flow (mol/min) of H 2 produced in the SRE; and F EtOH,inlet is the initial theoretical mole flow (mol/min) of ethanol at ambient temperature. Sensitivity analyses for temperature (400-700 • C) and different Rh-Pt ratios in the catalyst were performed in order to build a surface response in Design Expert 8 software.…”

“…However, the use of ethanol/gasoline mixtures in Base metals, such as Ni [15], Co [16], and Fe [17], and noble metals, such as Pd [18], Rh [18,19], Pt [7,20], and Ir [21], supported on metals oxides to catalyze SRE have been widely studied. The nature of the catalyst and operational conditions directly affect its performance in SRE [15,22]. Ni is a widely studied catalyst due to its low cost [10].…”