Hydrogen production from tar steam reforming over hydrangea-like Co-phyllosilicate catalyst derived from Co/Sepiolite

Abstract

Co-phyllosilicate with structure flexibility is acknowledged as a promising catalyst for hydrogen production by steam reforming. In this work, a series of hydrangea-like Co-phyllosilicate catalysts were synthesized by a template-free urea hydrothermal method, where the silica source was supplied by amorphous sepiolite. Both the exsolution property of phyllosilicate and the hierarchical macro-/meso-pore architectures of hydrangea-like morphology were combined to improve the metal dispersion and reactant activation. The catalytic behaviors of as-synthesized xCo/SEP-PS catalysts were evaluated in simulated tar (phenol + ethanol) steam reforming. It was founded that 10Co/SEP-PS catalyst achieved an optimal conversion (89.3%) and H2 yield (67.4%) at 700 °C, as well as the lowest apparent activation energy of 35.5 kJ/mol. Various characterization results coupling with experimental investigations indicated that the fine Co particles implanted on Co-phyllosilicate lamella were highly stable and active for H2 production. Meanwhile, the hydrangea-like Co-phyllosilicate provided high Lewis acidity and developed pore structure, significantly facilitating the reactant adsorption and activation, especially for phenol dehydrogenation. The synergy between developed pore structure and enhanced metal-support interaction of Co-phyllosilicate conferred 10Co/SEP-PS with a robust durability in a 50 h stability test and effective resistance to metal sintering and coke deposition.