A Comparative Evaluation of Physicochemical Properties and Photocatalytic Efficiencies of Cerium Oxide and Copper Oxide Nanofluids

Abstract

Copper oxide (CuO) and cerium oxide (CeO2) of various concentrations have been prepared through an ultrasonically assisted dispersion of CuO and CeO2 nanoparticles (NPs) in which water and nanofluids (NFs) were formulated. The morphological properties of the CuO and CeO2 NPs are reported. Few of the physicochemical properties that can influence the photocatalytic activities of the NFs are evaluated, such as viscosity, activation energy, density, thermal conductivity, electrical conductivity, alternating current (AC) conductivity, pH, stability, refractive index and optical band gap of the CuO and CeO2 NFs. Viscosity studies have been made at four different temperatures (303 K, 308 K, 313 K and 318 K) and the activation energy is calculated and compared between the CuO and CeO2 NFs. The thermal conductivity of the two NFs is calculated and compared. Electrical conductivity is measured for CuO and CeO2 NFs using an impedance analyzer at different frequencies at 303 K. The dielectric constant and AC conductivity were studied. The electrical conductivity and pH of the prepared NFs are measured and the results are compared. The stability of the NFs is determined from Zeta potential values obtained from dynamic light scattering measurements. UV-Visible diffuse reflectance measurements were used to deduce the optical bandgap of the respective metal oxide NPs in the NFs. The photocatalytic efficiencies of the CuO NFs and CeO2 NFs were evaluated using methylene blue (MB) as the model dye. The rate constant for the photodegradation of MB was higher for CuO NF as compared CeO2 NF and also higher than simple NPs-based photocatalysts. A plausible explanation for the role of NFs over the simple NPs-based photocatalytic solution is presented.

Studies on the Functional Properties of Titanium Dioxide Nanoparticles Distributed in Silyl–Alkyl Bridged Polyaniline-Based Nanofluids

“…The prediction of the density of rGO-Fe 3 O 4 -TiO 2 ternary hybrid/EG-based NF with the correlation over the concentration of NPs has been detailed [ 72 ]. It also must be noted that physical properties such as Gibbs free energy, internal pressure, molar volume, free volume, adiabatic compressibility, and other molecular interaction characteristics can influence the density of NFs [ 73 , 74 , 75 ]. Notably, the results from a few studies on TiO 2 /EG NFs that focused on thermal or rheological properties are available [ 76 , 77 , 78 , 79 ].…”

Enhancing photocathodic protection with Bi quantum dots and ZIF-8 nanoparticle co-sensitized TiO2 nanotubes

“…Based on these issues and future advanced applications, it is necessary to develop modified materials based on TiO 2 to enhance the photochemical properties for better applications. Strategies are continuously being developed to modulate the properties of TiO 2 to achieve improved performance [13][14][15], including oxygen defect generation, chemical (metallic or non-metallic) adulteration, surface sensitization/modification [16][17][18] and the incorporation of additional semiconductors or components to form a nanocomposite/hybrid material for a multitude of uses [19,20]. Additionally, ordered TiO 2 nanotubes (NTs) have been extensively researched and exploited in numerous applications due to their superior charge transport characteristics and photocatalytic efficiency [21].…”

Impact of bimetal doping on the structural and optical characteristics of copper oxide nanoparticles to enhance photocatalytic degradation of dyes: an investigative study

“…The addition of transition metal/ inner transition metal acts as an optical antenna to focus the sunlight on the photocatalyst's surface thereby increasing the photocatalytic activity. The optical activities of photocatalyst depends on the band gap which can be altered by narrowing the band gap results in enhancement of absorption of light in visible spectrum [15][16][17][18][19][20][21][22][23][24][25][26].…”