Investigation of Ni/SiO2 catalysts prepared at different conditions for hydrogen production from ethanol steam reforming

Abstract

Ni/SiO2 catalysts prepared by a sol-gel method have been investigated for hydrogen production via steam reforming of ethanol using a continuous flow, fixed bed reactor system. Chemical equilibrium calculations were also performed to determine the effects of temperature and molar steam to carbon ratio on hydrogen production. The acidity of the preparation solution (modified by nitric acid and ammonia) and calcination atmosphere (air and N2) were investigated in the preparation of the catalysts. BET surface area and porosity, temperature-programmed oxidation (TPO), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to characterise the prepared catalysts. The BET surface area was reduced when the solution acidity was lowered during the sol-gel preparation process. A pH value less than 2.0 was necessary to achieve high metal dispersion in the catalyst. Smaller NiO particles were obtained when the catalyst was calcined in N2. Material balances on ethanol steam reforming at 600 C using the prepared Ni/SiO2 catalysts were determined, and higher hydrogen production with lower coke deposition on the reacted catalysts were also obtained from the catalysts calcined in N2 atmosphere.

Ethanol steam reforming on Ni/CaO catalysts for coproduction of hydrogen and carbon nanotubes

“…Two‐stage fixed‐bed reactor has been adopted to perform ethanol reforming test. The reactor setup is shown in Figure , which is similar to our previous work . The ethanol and water mixture with S/C molar ratio of 3 was preheated to 250°C in the first reactor, which was inoculated in first reactor by a syringe pump.…”

“…In a study of Kim et al, 30% Ni/SBA‐15 catalyst, S/C ratio of 1.5, and 550°C to 800°C temperature range have been employed for ethanol steam reforming, and the corresponding hydrogen yield could reach about 70% at 700°C. Wu et al obtained a maximum hydrogen yield of 72.0% at 20% Ni/SiO 2 catalyst, S/C ratio of 4, and reforming temperature of 600°C from ethanol steam reforming. These revealed that the performance of the synthesized Ni/CaO catalysts is analogous with other ethanol steam reforming catalysts.…”

“…Among these methods, catalytic ethanol steam reforming is promising because ethanol is low volatile and nontoxic, and is easy to handle and transport. In addition, it has a high content of hydrogen, and it can be stored easily …”

Improved H2 Production by Ethanol Steam Reforming over Sc2O3-Doped Co-ZnO Catalysts

“…It is well known that most of the catalyst deactivation of ESR is attributed to the active metal sintering and the deposition of various type of carbon on the surface of the catalyst [41,42]. How to solve these problems is the main challenge in this field.…”

Effect of Supports and Promoters on the Performance of Ni‐Based Catalysts in Ethanol Steam Reforming

“…Apart from the nature and composition of the mixed oxides, the different preparation methods of these mixed oxides have been studied to achieve high hydrogen yields , , , , , , . The sol‐gel method can produce a mesoporous structure of the catalysts , , , , , , which can improve the mass transfer efficiency and diminish the deactivation rate . For a zeolite as the support, the sol‐gel incipient wetness impregnation (SIWI) method produces a hierarchical structure, improving the catalyst stability .…”