Rapid sol-gel synthesis of honeycomb-layered Na3Ni2BiO6 and orthorhombic Na3Ca2BiO6

The A(3)M(2)M ' O-6 type materials Na3Ca2BiO6 and Na3Ni2BiO6 were successfully synthesised through two sol-gel techniques - a method based on a natural deep eutectic solvent, and a biopolymer-mediated synthesis. The materials were analysed using Scanning Electron Microscopy to determine if there was a difference in final morphology between the two methods, and it was found that the natural deep eutectic solvent method resulted in a more porous morphology. For both materials, the optimum dwell temperature was found to be 800 degrees C, which in the case of Na3Ca2BiO6 was a much less energy-intensive synthesis process than its seminal solid-state synthesis. Magnetic susceptibility measurements were undertaken on both materials. It was found that Na3Ca2BiO6 exhibits only weak, temperature independent paramagnetism. Na3Ni2BiO6 was found to be antiferromagnetic, with a Neel temperature of 12 K, in line with previously reported results.

Automated summary

Two sol-gel techniques, one based on a natural deep eutectic solvent and the other on a biopolymer-mediated synthesis, were successfully used to synthesize the A(3)M(2)M ' O-6 type materials Na3Ca2BiO6 and Na3Ni2BiO6. Scanning Electron Microscopy analysis revealed a more porous morphology in the material synthesized using the natural deep eutectic solvent method. Both materials exhibited optimal dwell temperature of 800 degrees C, which was found to be a less energy-intensive synthesis process for Na3Ca2BiO6 compared to its solid-state synthesis. Magnetic susceptibility measurements showed weak, temperature independent paramagnetism in Na3Ca2BiO6 and antiferromagnetism with a Neel temperature of 12 K in Na3Ni2BiO6, consistent with previous results.