Nucleation front instability in two-dimensional (2D) nanosheet gadolinium-doped cerium oxide (CGO) formation

Abstract

Herein we report for the first time the synthesis of ceramic-organic three-dimensional (3D) layered gadolinium-doped cerium oxide (Ce1-XGdXO2-δ, CGO) and its exfoliation into two-dimensional (2D) nanosheets. We adopt a water-based synthetic route via a homogenous precipitation approach at low temperatures (10-80 °C). The reaction conditions are tuned to investigate the effects of thermal energy on the final morphology. A low temperature (40 °C) morphological transition from nanoparticles (1D) to two-dimensional (2D) nanosheets is observed and associated with a low thermal energy transition of ca. 2.6 kJ mol-1. For the 3D-layered material, exfoliation experiments are conducted in water/ethanol solutions. Systems at volume fractions ranging from 0.15 to 0.35 are demonstrated to promote under ultrasonic treatment the delamination into 2D nanosheets.