Micrograph of the July from the Journal of Sol-Gel Science and Technology

Each month, the ISGS Newsletter features an interesting and striking micrograph (or series of micrographs) chosen from a recent issue of the Journal of Sol-Gel Science and Technology or from unpublished sources such as PhD theses, etc (with full attribution given). If you know of any interesting images that might be suitable, please contact the ISGS Newsletter Editor for inclusion. The micrographs can be optical, SEM, TEM, AFM, etc, and a brief description of the samples should be provided.

The first is taken from the work of Chen, Qian, Sun, Song, Liu, and Lyu entitled “Grain size engineering and growth mechanism in hydrothermal synthesis of Bi0.5 Na0.5 TiO 3 thin films on Nb-doped SrTiO 3 substrates” (JSST, (2021), https://doi.org/10.1007/s10971-021-05586-y), which explores the effect of varying mineraliser concentrations on the morphology of epitaxially-grown thin films on single-crystal substrates. Decreasing the concentration of the mineraliser (NaOH) from 10 M (left-side image) to 6 M (right-side image) transforms the large rectangular, randomly-oriented grains (with an average size of 250 nm) into smaller rectangular grains (average size of 135 nm) which are more uniformly oriented on the substrate to yield a relatively flat surface. Such grain-size engineering provides a facile approach for optimising the energy-storage density and efficiency of devices such as thin-film capacitors.

The second series of micrographs is from the work of Shen, Jiang, Li, Yang, Zhang, Zhang and Pan entitled “Hydrogen production by ethanol steam reforming over Ni-doped LaNix Co1−x O 3− δ perovskites prepared by EDTAcitric acid sol–gel method” (JSST, (2021), https://doi.org/10.1007/s10971-021-05588-w). This paper describes the structure and morphology of the title perovskite nanocomposite catalysts and the effect of composition (x=0, 0.5, 0.9) and operating parameters (reforming temperature, H2 O:EtOH) on the ethanol steam reforming efficiency for the production of hydrogen from an ethanol feed. The micrographs illustrate the intriguing morphology of the optimum composition (x=0.5) before (left) and after (right) reduction in H2 .