They are separated by a band-gap of appropriate energy. The electronic structure of semiconductors, such as SONPs, has two band structures, the valence and conduction bands. The particle size of SONPs determines the electronic structure and it affects the interaction toward complementary catalyst or substrate, finally influencing the overall catalytic performance. However, the fabrication of SONPs with a targeted size and shape is another challenging topic.

The synthesis of Ag 2O is fairly simple as the reaction spontaneously occurs through acid (Ag +)-base (O 2−) adduct formation. As the sol–gel process involves the conversion of monomers into sol that acts as the precursor for gel, all the reactants are integrated into the final product. As an alternative for the precipitation method, a sol–gel route can be utilized. Although precipitation is the simplest method to produce Ag 2O, ion sources can remain unreacted, resulting in a non-stoichiometric problem. In general, SONP is synthesized through a precipitation method in which Ag +(aq) is titrated with an alkaline solution, e.g., NaOH(aq), to obtain silver oxide (Ag 2O). Furthermore, SONP-based ternary oxides show fine-tuned catalytic performance as the variable coordination environments made by multi-components influence electronic structure and redox behaviour. The SONP itself is utilized in photoelectrochemical or photocatalytic applications. As a semiconducting material, SONPs are known to have a wide band-gap from 1.3 to 2.4 eV, making them suitable for photocatalytic applications, especially with the visible light-harvesting ability. Silver oxide nanoparticles (SONPs) have been widely studied due to their unique optoelectronic property and high antibacterial activities. LDH with an appropriate ratio could be utilized as a substrate to grow silver oxide nanoparticles with controlled size with effective antibacterial performance. The small particle size and homogeneous distribution of silver oxide showed advantages in antibacterial efficacy compared with bulk silver oxide.

X-ray photoelectron spectroscopy and UV-vis spectroscopy results suggested that the high Ag/Al ratio tended to produce silver oxide with a complex silver environment. At the lowest silver ratio, the particle size was the smallest, while the chemical purity was the highest. The particle size, homogeneity and purity of silver oxide were influenced by the stoichiometric ratio of Ag/Al. X-ray diffraction, X-ray photoelectron spectroscopy, and microscopic measurements clearly showed the development of nano-sized silver oxide particles on the LDH surface. The released hydroxyl and citrate acted as a reactant in crystal growth and a size controlling capping agent, respectively. The lattice of LDH was partially dissolved during the reaction by Ag +.

Silver oxide nanoparticles with controlled particle size were successfully obtained utilizing citrate-intercalated layered double hydroxide (LDH) as a substrate and Ag + as a precursor.

Spacechem random oxides