Porous gadolinia-doped ceria with adjustable pore sizes using PI-b-PEO copolymer as the structure-directing agent

Abstract

In this study, we report that by coupling the kinetics of both hydrolysis and condensation of the oxide precursors and the kinetics of self-assembly process of the block copolymer, we can synthesize both mesoporous and macroporous gadolinia-doped ceria (GDC) with one chemical composition but different processing conditions. Our process uses poly(isoprene-b-ethylene oxide) as the structure-directing agent and cerium and gadolinium acetylacetonates as the precursors for the sol–gel synthesis of GDC. By controlling the extent of the hydrolysis and condensation of the oxide precursor before mixing with the copolymer, we can adjust the hydrophilic domain size from nanometers to micrometers. As a result, highly crystalline porous GDC with dominant mesopores (15 nm < d < 50 nm) or macropores (50 nm < d < 5 μm) are produced after removal of the copolymer via a two-step calcination treatment. The discovery of this study offers a facile and viable approach to produce meso- and macro-porous materials, in a ‘one-pot’ synthesis with one chemical composition but different processing conditions to control pore sizes.