Micrograph of the Month(s) 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(or series of micrographs) chosen from a recent issue of the Journal of Sol-Gel Science and Technology or from unpublished sources such as PhD theses, etc (with full attribution given).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 micrographs are taken from the work of Mohana, Swathi, Yuvakkumar, Ravi and Arun Metha entitled “Ni (OH)2/Co(OH)2 nanocomposite as electrocatalyst towards water oxidation process” ((JSST (2024) 110, 90-102; https://doi.org/10.1007/s10971-024-06341-9). This work explores the synthesis and characterisation of a nano- composite for the electrochemical oxidation of water. The micrographs illustrate the intriguing urchin-like mor-phology of the nano-composite (right image), compared to the wrinkled and needle-like structures of Ni(OH)2 and Co(OH)2 (left and middle images, respectively). The electrochemical surface area of the nano-composite was 265 cm2/g, which was substantially higher than that of pure Ni(OH)2 and Co(OH)2 (108 and 96 cm2/g, respectively), suggesting potential applications as an electrocatalytic material for sustainable energy applications.


The second series of micrographs is from the work of Ghotekar, Ravikumar,, Chauhan, Hikku, Lin,, Rahdar, Hit-ler, Jabir, Marzban and Oza. This paper, entitled “Eco-friendly fabrication of CdO nanoparticles using Polyalthia longifolia leaves extract for antibacterial and electrochemical sensing studies” (JSST, (2024) 110, 221-232; https://doi.org/10.1007/s10971-024-06352-6), explores the synthesis of CdO nanoparticles for applications as antibacterial agents and electrochemical sensing of glucose and dextrose. The micrographs reveal an unusual anisotropic morphology consisting of CdO nanowires decorated with less welldefined CdO nanostructures, with no other crystalline compounds being identified. The unusual anisotropic morphology obtained was attributed the interactions between Cd(II) ions and compounds such as quercetin present in the leaf extract during evolution of CdO.

The third series of images is from the work of Hu, Tang, Wu, Xu, Li, Wang, Feng, Jiang, Liang and Liu entitled “Facile synthesis, characterization, biocompatibility and protein loading/release property of zinc-doped hollow mesoporous bioactive glass nanospheres” (JSST, (2024); https://doi.org/10.1007/s10971-024-06374-0). This paper explores the synthesis and properties of hollow mesoporous zinc-doped bioactive glass nanospheres, their behaviour in simulated body fluid (SBF) and their capacity to encapsulate and release bovine serum albumin (BSA) as a model protein. Micrographs A and B illustrate the TEM images of the hollow glass spheres obtained in the absence and presence, respectively, of Zn indicating that Zn doping does not significantly alter the apparent morphology of the hollow spheres. However, the inclusion of Zn has a significant impact on the formation of surface hydroxy apatite, with the incorporation of Zn essentially suppressing its formation (compare micrographs C and D, for samples without and with Zn, respectively). Both samples exhibited significant uptake of BSA within the hollow core, with loadings exceeding 200 mg/g being obtained, together with sustained release over a 15-day period. The authors proposed the potential use of the hollow spheres as carriers for protein or drug molecules in applications such as tissue regeneration.


(BSA) as a model protein. Micrographs A and B illustrate the TEM images of the hollow glass spheres obtained in the absence and presence, respectively, of Zn indicating that Zn doping does not significantly alter the appar-ent morphology of the hollow spheres. However, the inclusion of Zn has a significant impact on the formation of surface hydroxy apatite, with the incorporation of Zn essentially suppressing its formation (compare micrographs C and D, for samples without and with Zn, respectively). Both samples exhibited significant uptake of BSA within the hollow core, with loadings exceeding 200 mg/g being obtained, together with sustained release over a 15-day period. The authors proposed the potential use of the hollow spheres as carriers for protein or drug molecules in applications such as tissue regeneration.

The final series of images is from the work of Luo, Xu, Miao, Song, Wu, Yin, Duan, and Song. This paper, entitled “Freeze-cast porous silica ceramics with alumina nanofibers addition” (JSST, (2024); https://doi.org/10.1007/s10971-024-06364-2), describes the effect of processing variables on the synthesis and of porous silica ceramics reinforced with alumina nanofibers. Samples prepared with a silica:alumina-fibre mass ratio of 4.8 exhibited an intriguing fibrous structure within the pore wall (micrographs (a) and (b)). Increasing silica content led to a more uniform porewall morphology, as illustrated in micrographs (c) and (d), for which the silica: aluminafibre mass ratio was 9.7. Increasing silica content led to a decrease in sample porosity and to a corresponding in-crease in compressive strength and thermal conductivity.