Particle size is an important parameter for materials characterization. It can be determined using TEM, SEM, AFM, and other microscope techniques. These techniques are used for the solid-state form. Particle size distribution (PSD) can be obtained via the analysis of large particle numbers. The analysis of the particle size of a particle dispersed in a liquid can be evaluated using different techniques such as dynamic light scattering (DLS), and laser diffraction spectroscopy (LDS). Based on the sources i.e., light or laser, these techniques are named. DLS data is affected by several parameters such as temperature, and concentration. The theory of the DLS analysis is based on the spherical particle. Thus, it isn't reliable data for particles with other morphologies. Other techniques such as nanoparticle tracking analysis (NTA) can be also used for visualizing and analyzing particles in liquids following Brownian motion. NTA can be used for the determination of a size distribution profile of particles with a diameter of 10-1000 nm. Both DLS and NTA are based on the Brownian motion. The main difference is in the analysis strategies. NTA is based on video-individual particle positional changes, while, DLS visualizes the total particles using a digital correlator. . The materials were reported for three main areas of research including energy, environmental, and biomedicine. The applications in the energy field can be 1) hydrogen generation via hydrolysis of sodium borohydride (NaBH4), 2) photocatalytic water splitting for hydrogen generation , 3) photocatalytic alcohol oxidation for hydrogen generation and carbonyl compounds synthesis ; 4) supercapacitors , 5) lithiumion battery, and 6) dye-sensitizing solar cells (DSSCs) . The applications for environmental-based technology can be 1) water treatment via pollutants removal e.g., adsorption and degradation, 2) air purification; removal of greenhouse gases via adsorption , 3) adsorption/photocatalytic oxidation of volatile organic compounds (VOCs) , 4) photocatalytic degradation of drugs, antibiotics, and pharmaceuticals , 5) heavy metal removal via adsorption , and 6) precious metal recovery . Biomedical applications can be 1) cancer therapy; chemotherapy, photodynamic, and photothermal, 2) drug delivery , 3) gene delivery using cell-penetrating peptides (CPPs) Over 80% of industrial processes use catalysis, accounting for $1.5 trillion in yearly global sales, or 35% of the global GDP . The oxidation of organic compounds like alkenes/olefins, alcohol, and dyes is one of several catalytic processes that is crucial for environmental concerns and the production of fine chemicals like medications, paints, and surfactants. The chemical synthesis of useful and valuable compounds depends on the conversion of alcohols by an oxidation process to aldehydes. Additionally, some applications need the catalytic oxidation process, including the oxidation of air pollutants , volatile organic compounds (VOCs) , and aqueous pollutants for water treatment .