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In this work, we first report a novel sodium-enriched Ni–Fe mixed-oxide catalyst incorporated into a Ni–P electrode for photo- and electrocatalytic water splitting.

Inspired by the applications in electromagnetic nanomaterials processing in enclosures and hybrid fuel cell technologies, a mathematical model is presented to analyze the mixed convective flow of electrically conducting nanofluids (gamma-Al2O3-H2O and gamma-Al2O3-C2H6O2) inside a square enclosure saturated with porous medium under an inclined magnetic field. The Tiwari-Das model, along with the viscosity, thermal conductivity, and effective Prandtl number correlations are considered in this study. The impacts of Joule heating, viscous dissipation, and internal heat absorption/generation are taken into consideration. Strongly nonlinear conservation equations which govern the heat transfer and momentum inside the cavity with associated initial and boundary conditions are rendered dimensionless with appropriate transformations. The Marker-And-Cell (MAC) technique is deployed to solve the non-dimensional initial-boundary value problem. Validations with previous study are included. A detailed parametric study is carried out to evaluate the influences of the emerging parameters on the transport phenomena. When 5% gamma-Al2O3 nanoparticles are suspended into H2O base-fluid, the average heat transfer rate of gamma-Al2O3-H2O nanoliquid is increased by 25.63% compared with the case where nanoparticles are absent. When 5% gamma-Al2O3 nanoparticles are suspended into C2H6O2 base-fluid, the average heat transfer rate of gamma-Al2O3-C2H6O2 nanofluid is increased by 43.20% compared with the case where nanoparticles are absent. Further, when heat source is present, the average heat transfer rate of gamma-Al2O3-C2H6O2 nanofluid is 194.92% higher than that in the case of gamma-Al2O3-H2O nanofluid.

The objective of this paper is to investigate the energy transmission rate's features of the natural convective radiative [Formula: see text] nanofluid and [Formula: see text] hybrid nanofluid flow in a tilted square porous cavity under the influence of heat source/sink. The marker and cell method is adopted to solve the system of partial differential equations. The outcomes explore that in the existence of heat source, by augmenting the volume fraction of spherical-, cylindrical-, column-, and lamina-shaped nanoparticles from 1% to 5% in water, the average heat transfer rate is boosted by 6.07%, 8.36%, 9.89%, and 14.95%, respectively. In the existence of heat sink, the increment is noticed as 2.67%, 3.68%, 4.37%, and 6.64%, respectively. Therefore, the shape of the nanoparticles considerably varies the heat transfer rate. In the existence of heat source, by magnifying the volume fraction of spherical-, cylindrical-, column-, and lamina-shaped [Formula: see text] nanoparticles from 1% to 5% in water, the mean heat transfer rate is magnified by 7.23%, 11.03%, 14.15%, and 31.36%, respectively. In the existence of heat sink, the magnification is detected as 3.18%, 4.87%, 6.27%, and 14.09%, respectively. This result confirms that the proper combination of nanoparticles considerably enhances the heat transfer characteristics of base fluids. The findings of this study may be helpful for a better understanding of hydrothermal features of thermal systems such as heat exchangers, helical heat sinks, solar collectors, periodic pin-fins, mini shell and tube heat exchangers, plate evaporators, photothermal cancer treatment, and microvascular vessels using various unitary and hybrid nanofluids.

Heat transfer in a magnetohydrodynamic (MHD) micropolar fluid through a squeezing channel in the presence of viscous dissipation and Joule heating is studied. The analysis is carried out over different water based nanofluids consisting of alumina (Al2O3), titania (TiO2), and magnetite (Fe3O4) nanoparticles. A model with non-linear partial differential equations is converted to a set of non-linear ordinary differential equations by the aid of similarity transformations. The resulting equationsare then numerically solved by Runge–Kutta (RK) method with fourth order approximation followed by shooting method. A comprehensive investigation describing the influences of the physical parameters such as vortex viscosity parameter, ohmic heating parameter, Hartmann number, squeezing parameter and solid volume fraction parameter on the distributions of temperature, velocity and microrotationis are graphically showed. In the absence of squeezing and expanding, it is observed that both water and nanofluid experience same viscous drag. Further, an increase in volume fraction lowers the microrotation, and thereby causing an elevation in the temperature of titania–water nanofluid. This is in contrast to the behaviour of the other nanofluids.