arXiv subjects

Salma Touili

Publications and source records attributed to Salma Touili.

4 recordsLinked to original sources

arXiv2026

Improvement of piezocatalytic performance of Na0.5Bi0.5TiO3 perovskite using K doping for efficient Rhodamine B degradation

Piezocatalysis, based on the piezoelectric properties of catalysts, breaks down the barrier between mechanical energy and chemical energy. It describes the use of charges induced by piezoelectricity to assist typical chemical processes while harvesting various forms of mechanical green energy. The performance of piezocatalysis is predominantly governed by the piezoelectric properties of materials. The main aim of this work is to evaluate and analyze the potential of potassium doped sodium bismuth titanate Na0.5-xKxBi0.5TiO3 abbreviated as NKxBT (0, 0.15, 0.20, and 0.25), as a piezocatalyst in the degradation of the organic dye Rhodamine B RhB under ultrasonic vibration. The synthesis of NKxBT nanopowders was conducted using the sol-gel autocombustion method. Coupled structural analysis reveals the presence of an intermediate Morphotropic Phase Boundary (MPB, where two phases coexist) in the optimal NK15BT composition. The piezocatalytic degradation results showed a total piezo-degradation in only 90 min and a rate constant 8 times higher than the undoped NK0BT. The enhanced piezocatalytic activity results from a synergistic effect of MPB presence, reduced particle size, optimal bandgap and high lattice strain. The NK15BT sample also demonstrated good reusability and good mineralization.

cond-mat.mtrl-sci↗

arXiv2026

Role of Bi3+ ion substitution on the piezocatalytic degradation performance of lead-free BaTi0.89Sn0.11O3 at low vibrational energy

Harnessing low ultrasonic vibration energy to drive piezocatalytic reactions has attracted increasing attention in response to current environmental and energy challenges. In this study, we investigate the effect of heterovalent bismuth doping on the piezocatalytic degradation of Rhodamine B (RhB) under low-power ultrasonic excitation. Bismuth ions (Bi$^{3+}$) were substituted into the lead-free ferroelectric BaTi${0.89}$Sn${0.11}$O$_3$, yielding BTSn11-xBi with x = 0, 0.02, and 0.04. The powders were synthesized by the sol-gel method as submicron cubes. The structural, morphological, optical, and piezocatalytic properties were strongly influenced by the Bi content. Compared with pristine BTSn11 and BTSn11-0.04Bi, the BTSn11-0.02Bi sample exhibited the lowest band gap (3.22 eV), the smallest particle size (283 nm), the highest piezoelectric current (approximately 8 microA cm$^{-2}$), and the lowest coercive field required to obtain piezoresponse force microscopy hysteresis loops. As a result, BTSn11-0.02Bi showed the highest RhB degradation efficiency and the largest apparent kinetic rate constant, confirming its superior piezocatalytic performance. Total organic carbon measurements revealed significant mineralization of RhB. In addition, BTSn11-0.02Bi demonstrated good reusability and stability, maintaining high degradation efficiency over three consecutive cycles. These results highlight the potential of Bi-doped BTSn11 ferroelectric materials, particularly BTSn11-0.02Bi, as efficient piezocatalysts for environmental remediation.

cond-mat.mtrl-sci↗

arXiv2026

Ferroelectric KNbO3 nanoplatelets for thermally driven pyrocatalytic hydrogen evolution and dye degradation

Day- and night-induced thermal cycling offers a promising route for harvesting ambient thermal energy to drive sustainable hydrogen production and pollutant degradation. Pyroelectric materials enable this process by converting temperature fluctuations into surface charges capable of promoting catalytic water splitting and advanced oxidation reactions. In this work, we demonstrate efficient pyrocatalytic hydrogen evolution and Rhodamine B (RhB) degradation using orthorhombic ferroelectric Potassium niobate (KNbO$_3$) nanoplatelets (KN-np). Under thermal cycling between 20 and 50 $^\circ$C, KN-np achieved a hydrogen yield of 680 $μ$mol g$^{-1}$ after 30 thermal cycles, corresponding to an average hydrogen production rate of 22.67 $μ$mol g$^{-1}$ per cycle. In addition, KN-np exhibited excellent pyrocatalytic activity toward RhB degradation, reaching 84% removal after only 16 thermal cycles with an apparent kinetic rate constant of 0.11 cycle$^{-1}$. The remarkable catalytic performance is attributed to the strong spontaneous polarization and excellent pyroelectric properties of the KNbO$_3$ nanoplatelets, which promote efficient charge generation and interfacial redox reactions. These findings highlight the potential of KNbO$_3$ nanostructures as efficient pyrocatalysts for clean hydrogen production and environmental remediation.

cond-mat.mtrl-sci↗

arXiv2026

Enhancement in Magnetic and Magnetocaloric Properties of CoFe2O4 Nanofibers at Lower Temperatures

This research paper investigates new and first insights into the magnetic and magnetocaloric properties of one-dimensional (1D) cobalt ferrite CoFe2O4 (CFO) nanofibers elaborated by sol gel based electrospinning technique, particularly focusing on their behavior at low temperatures for specific applications. The calcined CFO nanofibers microstructural, structural, magnetic, and magnetocaloric properties were explored. The nanofibers (NFs) microstructure, with an average diameter of 210 nm, was examined by scanning and transmission electron microscopies (SEM, TEM). The X-ray diffraction (XRD) of the CFO nanofibers showed a pure cubic close-packed (c.c.p) spinel crystalline structure with the F d 3 -m space group. The Raman spectroscopic studies further confirm the cubic inverse spinel phase. The Magnetic properties were explored as a function of temperature, ranging from 10 to 300 K, a ferromagnetic behaviour was observed with the highest saturation magnetization of 75.87 emu g(-1) and a coercivity of 723 Oe at room temperature. The variation of the magnetic entropy was measured indirectly using the Maxwell approach with an increasing magnetic field. A maximum of Delta(S)=1.71 J K-1 was reached around 32 K. At 180 K, the associated adiabatic temperature change, Delta (Tmax), was 0.93 K, with a large RCP value of 7.58 J kg-1 was measured, which is reasonably high for the corresponding nanoparticles (NPs). This work may suggest that 1D CFO nanofibers offer a promising route for the production of nanostructured magnetic materials, potentially impacting various electronic and electromagnetic device applications at low temperatures.

cond-mat.mtrl-sci↗