Synergistic effect of transition metals substitution on the catalytic activity of LaNi0.5M0.5O3 (M = Co, Cu, and Fe) perovskite catalyst for steam reforming of simulated bio-oil for green hydrogen production

Abstract

Hydrogen is considered an excellent source of renewable and sustainable energy which can be produced from inexpensive starting materials such as biomass. The present study aims at developing a stable catalytic system for bio-oil steam reforming process to produce green hydrogen. The perovskite catalysts LaNi0.5M0.5O3 (M = Co, Cu, and Fe) were synthesized using sol-gel method and their catalytic performance towards hydrogen production and bio-oil conversion was evaluated in a fixed bed tubular reactor. A wide array of techniques such as XRD, BET, NH3 and CO2 -TPD, FE-SEM, XPS, TGA and pyridine-FTIR were used to analyze the material properties of the synthesized catalysts. The results of these analyses verified the successful formation of the highly sought-after perovskite structure with good amount of surface oxygen vacancies as well as medium-strength acidic and basic sites. To establish an efficient catalytic system, process parameter (space-time and reaction temperature) optimization and time on stream (TOS) studies were conducted. The TOS results displayed that LaNi0.5Co0.5O3 perovskite catalyst is stable up to 12 h at 700 °C for space-time of 17.4 kgcat. h/kgmolbio-oil. In-depth characterizations (FE-SEM, TGA, RAMAN spectroscopy and XRD) of spent catalyst after the reaction not only gave further insights about the excellent activity exhibited by the chosen catalyst but also revealed information about the nature of the coke deposited on the surface.