Macedonian Journal of Chemistry and Chemical Engineering

Enhancing TiO2 photocatalytic efficiency through the synergistic effect of titania/ceria binary oxide and silver doping

Sat, 16 May 2026 00:00:00 +0000

In this study, a modified sol–gel method was used to synthesize pure TiO₂ and TiO₂/CeO₂-based materials, followed by the loading of 3 wt.% silver ions onto the catalyst surfaces using a wet-impregnation method. All synthesized and modified catalysts were characterized using Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques to analyze their textural, morphological, and structural properties. The photocatalytic activity of these materials was evaluated for the degradation/decolorization of crystal violet (CV) dye under ultraviolet (UV) irradiation. Moreover, the effects of various process parameters, including initial dye concentration, catalyst amount, and UV wavelength, on photocatalytic efficiency were analyzed. The results indicated that the addition of CeO₂ and Ag into the TiO₂ catalyst significantly enhanced the photocatalytic activity compared with pure TiO₂ under identical experimental conditions. Further analysis of the photocatalytic process demonstrated that the TiO₂/CeO₂ binary oxide catalyst, as well as Ag-doped samples (TiO₂/Ag and TiO₂/CeO₂/Ag), exhibited improved photocatalytic performance relative to pure TiO₂.

Decoding the features of important biochemical multistep electron-transfer pathways through the signatures of two-step double-regenerative electrochemical mechanism in square-wave voltammetry

Rubin Gulaboski — Sat, 16 May 2026 00:00:00 +0000

Results from theoretical analyses of a two-step double-regenerative electrochemical mechanism (schematically designated as EC’EC” mechanism), examined for the first time under conditions of square-wave voltammetry, are presented. The primary emphasis is on the relevance of this complex mechanism for getting a more comprehensive understanding of analogous mechanistic pathways that frequently operate under physiological conditions. Such complex mechanistic schemes are typical of many biologically important pathways in which coupled electron-transfer steps are linked to homogeneous regenerative reactions mediated by catalytic substrates, enzymes, stable radical species, or some redox cofactors. Through systematic analysis of the forward and backward square-wave current components, the role of regenerative loops associated with both electron-transfer steps in affecting the voltammetric response and generating distinct electrochemical–catalytic signatures is elucidated. The proposed framework encompasses for the first time the interplay between electron-transfer kinetics, chemical regeneration rates, and mass transport within the time scale imposed by square-wave excitation signal. The results establish a useful framework for a unified mechanistic interpretation of complex bioelectrochemical systems, while offering a robust theoretical basis for kinetic analyses of multistep redox pathways relevant to metabolic processes, enzymatic catalysis, and redox signaling in living organisms.

The influence of low-concentration additives of dimethyl sulfoxide and formamide on the stability and performance of lithium bis(trifluoromethanesulfonyl)imide-based electrolyte for lithium-ion batteries

Sat, 16 May 2026 00:00:00 +0000

The development of advanced electrolytes is essential for improving the stability and safety of lithium-ion batteries (LIBs). This study systematically investigated the effect of low concentrations of two polar additives, dimethyl sulfoxide (DMSO) and formamide (FA), in a lithium bis(trifluoromethane-sulfonyl)imide (LiTFSI) electrolyte with ethylene carbonate and diethylene carbonate (EC/DEC, 1:1 v/v). Electrolytes containing 2.5 wt% of each additive were prepared and evaluated for ionic conductivity, electrochemical stability window (ESW), Li-ion transference number, and cycling performance in graphite||Li⁺ half-cells relative to the blank electrolyte. Ionic conductivity measurements showed that both DMSO and FA reduced conductivity due to higher viscosity and stronger Li⁺ solvation. Linear sweep voltammetry (LSV) indicated that while the blank electrolyte exhibited a wide ESW of 5.45 V, the addition of 2.5 wt% DMSO and FA slightly narrowed the window to 5.15 V and 4.98 V, respectively. Both additives increased the Li-ion transference number compared to the blank. Cyclic voltammetry (CV) revealed that DMSO improved interfacial reversibility, whereas FA induced quasi-capacitive behavior with suppressed faradaic processes. However, galvanostatic cycling demonstrated that both additives led to poor coulombic efficiency and unstable cycling, likely due to incompatibility with the graphite anode. Galvanostatic charge-discharge (GCD) results further indicated that low concentrations of DMSO and FA did not enhance long-term cycling stability, probably due to irregular solid electrolyte interphase (SEI) formation, although they may hold potential for high-voltage cathode applications.