ZnO and Ti-doped ZnO (Ti-ZnO) nanoparticles were synthesized using rapid combustion. The morphology of ZnO and Ti-ZnO featured nanoparticles within cluster-like structures. The ZnO and Ti-ZnO structures exhibited similar hexagonal wurtzite structures and crystal sizes. This behavior occurred because Zn²⁺ sites of the ZnO lattice were substituted by Ti⁴⁺ ions. The chemical structure characterization implied the major vibration of the ZnO structure. The physisorption analysis showed similar mesoporous and non-rigid aggregation structures for ZnO and Ti-ZnO using N₂ adsorption–desorption. However, Ti-ZnO demonstrated a specific surface area two times higher than that of ZnO. This was a major factor in improving the photocatalytic degradation of methylene blue (MB). The photocatalytic degradation analysis showed a kinetic degradation rate constant of 2.54 × 10⁻³ min⁻¹ for Ti-ZnO, which was almost 80% higher than that of ZnO (1.40 × 10⁻³ min⁻¹). The transformation mechanism of MB molecules into other products, including carbon dioxide, aldehyde, and sulfate ions, was also examined.

Water hyacinth (Wh) is an aquatic weed considered a nuisance in agricultural and fishing activities. Therefore, this study proposed repurposing this plant into activated carbon (AC). First, the ZnO-AC was precipitated and applied as a photocatalyst for degrading methylene blue. The preliminary photocatalytic test under UV irradiation identified the optimum ZnO-AC photocatalyst to degrade methylene blue (MB). The ZnO-AC photocatalyst recorded the highest degradation rate constant of 11.49 × 10⁻³ min⁻¹, which was almost two-fold higher than that of ZnO (5.55 × 10⁻³ min⁻¹). Furthermore, photocatalytic degradation of MB and carbaryl under sunlight irradiation by ZnO-AC demonstrated degradation rate constants of 74.46 × 10⁻³ min⁻¹ and 8.43 × 10⁻³ min⁻¹, respectively. To investigate the properties of ZnO-AC, several techniques were performed. ZnO-AC and ZnO exhibited similar results in morphology, crystalline structure, and Raman characteristics. However, ZnO-AC presented smaller pore diameters than those of ZnO, which enlarged pore surface area, and the presence of carbon-related groups implied the presence of AC on ZnO-AC surfaces. This can be attributed to the presence of AC on the ZnO surface, increasing the capture of surrounding toxic molecules and elevating the reaction density. This mechanism is attributed to promoting the degradation of toxic molecules. Therefore, using Wh as a carbon source for the transformation of AC can alternatively solve the problems of aquatic weed management and carbon storage strategies, and the application of AC in ZnO-AC photocatalysts can enhance photocatalysis.

The effect of low oxygen-partial pressured carburizing on relaxation process for 316L stainless steel is reported. Phase, morphology, and amount of compound formation during initial stage of carburizing are investigated using X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). The results show formation and development of surface multilayer with nano-grain-carbide (Cr₇C₃, Fe₇C₃, and/or Cr₃C₂) generation in the layer located below outermost protective layer. The relaxation process has been investigated using electrochemical impedance spectroscopy (EIS). Formation of nano-grain carbide(s) during carburizing causes deterioration effect on the electrochemical behavior of steel. However, the steel with large amount of carbide generation (carburized for 30 min) tends to have higher corrosion resistance (indicated by higher values of R_cl and R_ct) than the smaller ones (10 and 20 min) due to the effect of phase, grain size, morphology, and amount of compound formation.

Martensitic stainless steel parts used in carbonaceous atmosphere at high temperature are subject to corrosion which results in a large amount of lost energy and high repair and maintenance costs. This work therefore proposes a model for surface development and corrosion mechanism as a solution to reduce corrosion costs. The morphology, phase, and corrosion behavior of steel are investigated using GIXRD, XANES, and EIS. The results show formation of nanograin–boundary networks in the protective layer of martensitic stainless steel. This Cr₂O₃–Cr₇C₃ nanograin mixture on the FeCr₂O₄ layer causes ion transport which is the main reason for the corrosion reaction during carburizing of the steel. The results reveal the rate determining steps in the corrosion mechanism during carburizing of steel. These steps are the diffusion of uncharged active gases in the stagnant–gas layer over the steel surface followed by the conversion of C into C⁴⁻ and O into O²⁻ at the gas–oxide interface simultaneously with the migration of Cr³⁺ from the metal-oxide interface to the gas-oxide interface. It is proposed that previous research on Al₂O₃ coatings may be the solution to producing effective coatings that overcome the corrosion challenges discussed in this work.

Fe-2.25Cr-1Mo a widely used material for headers and steam tubes of boilers. Welding of steam tube to header is required for production of boiler. Heat affected zone of the weld can have poor mechanical properties and poor corrosion behavior leading to weld failure. The cost of material used for steam tube and header of boiler should be controlled. This study propose a new materials design for boiler welding to improve the lifetime and cost control, using tungsten inert gas (TIG) welding of Fe-2.25Cr-1Mo tube to carbon steel pipe with chromium-containing filler. The cost of production could be reduced by the use of low cost material such as carbon steel pipe for boiler header. The effect of chromium content on corrosion behavior of the weld was greater than that of the microstructure. The lifetime of the welded boiler can be increased by improvement of mechanical properties and corrosion behavior of the heat affected zone.

The effects of a weak magnetic field on chemical reactions are still not well understood. In our research, we used a sparking discharge process to ionize and atomize different metal wires in ambient air under usual atmospheric conditions, with and without the presence of a magnetic field. Products were collected on a glass substrate and additionally characterized for the presence of nitrogen or nitride bonding with XPS. All samples sparked with no magnetic field provided an evidence of nitride formation. Additional characterization and comparison of samples prepared inside and outside a magnetic field was performed using FTIR and collected in deionized (DI) water to investigate the influence on conductivity and pH. When the magnetic field was present during sparking discharge, a higher concentration of nanoparticles was produced.