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Muhammad Shahriar Bashar

Publications and source records attributed to Muhammad Shahriar Bashar.

4 recordsLinked to original sources
arXiv2026

Sol-Gel-Derived NiO/ZnO Thin Films with Single and Heterostructure Layers for Electrochemical Energy Storage

NiO/ZnO-based thin films, including single-layer and heterostructure configurations, were synthesized to investigate the influence of stacking order on their electrochemical performance for supercapacitor applications. To improve the relatively low capacitive performance of ZnO compared to NiO, NaCl was introduced as a dopant. All films were deposited using a non-vacuum spin-coating method on fluorine-doped tin oxide (FTO) substrates, chosen for their excellent electrical conductivity and stability as electrode materials. The surface morphology and structural parameters were examined using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Optical properties were analyzed via UV-Vis spectroscopy, revealing direct band gaps in the range of 3.17-3.31 eV for ZnO and Na-ZnO, and wider gaps up to 3.81 eV for NiO. Electrochemical performance was evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in a three-electrode configuration with 1 M KOH as the electrolyte. Among the electrodes, the single-layer NiO film exhibited the highest specific capacitance of 1.391 Fg^{-1}. In contrast, the NiO/ZnO heterostructure demonstrated a synergistic effect, resulting in enhanced charge storage and achieving a maximum specific capacitance of 1.627 Fg^{-1} at a current density of 2.0 mA cm^{-2}. Furthermore, sodium doping significantly improved the capacitance of ZnO. Overall, the results highlight the potential of sol-gel-derived oxide heterostructures and doped thin films as cost-effective and scalable electrode materials for supercapacitors in portable electronics and energy storage systems.

cond-mat.mtrl-sci↗
arXiv2026

Mechanistic Insights into Enhanced Alkaline Oxygen Evolution on Zn-Al Alloy Electrodes

Electrochemical water electrolysis, which produces clean energy carriers to mitigate carbon emissions, lacks suitable, low-cost electrodes for efficient oxygen evolution reaction (OER) in alkaline water splitting. To address this challenge, we developed Zn-Al alloy electrodes with varying Al contents up to 20 wt.% via powder metallurgy method and conducted electrochemical measurements of the OER in alkaline solution to investigate their catalytic performance. We also performed first-principles calculations to examine their thermodynamic phase stability and electronic structures. Both theoretical and experimental results indicated that incorporating $\geq 20$ wt.% Al into Zn led to thermodynamic phase instability and secondary-phase segregation in Al-rich regions, limiting reaction kinetics and reducing catalytic efficiency. Although the Al content of 5 wt.% into Zn exhibited favorable thermodynamic and electronic characteristics, but its electrochemical performance was inefficient and poor due to inadequate reaction active sites on the surface. In contrast, the 10 wt.% and 15 wt.% Al into Zn showed approximately three- and two-fold increases in anodic exchange current density relative to pure Zn, respectively. Additionally, the anodic overpotential losses ($η_{0,a}$) measured at a current density of 12 mAcm$^{-2}$ were 0.240 V for Zn$_{0.9}$Al$_{0.1}$ and 0.5603 V for Zn$_{0.85}$Al$_{0.15}$, significantly lower than that of pure Zn ($η_{0,a} = 1.086$ V). While Zn$_{0.9}$Al$_{0.1}$ and Zn$_{0.85}$Al$_{0.15}$ showed similar charge transfer resistance ($R_{\rm CT}$), Zn$_{0.9}$Al$_{0.1}$ demonstrated superior reaction kinetics and lower $η_{0,a}$ across all samples tested. Furthermore, the improved kinetics and reduced overpotential of the Zn-Al alloys favorably compare with those of other transition-metal-based catalysts, including Fe-Co-Ni-Mo alloys and Fe-doped CuO.

cond-mat.mtrl-sci↗
arXiv2021

Room temperature ferroic orders in Zr and (Zr, Ni) doped SrTiO$_3$

We synthesized strontium titanate SrTiO$_3$ (STO), Zr doped $\text{Sr}_\text{1-x}\text{Zr}_\text{x}\text{Ti}\text{O}_3$ and (Zr, Ni) co-doped $\text{Sr}_\text{1-x}\text{Zr}_\text{x}\text{Ti}_\text{1-y}\text{Ni}_\text{y}\text{O}_3$ samples using solid state reaction technique to report their structural, electrical and magnetic properties. The cubic $Pm$-$3m$ phase of the synthesized samples has been confirmed using Rietveld analysis of the powder X-ray diffraction pattern. The grain size of the synthesized materials was reduced significantly due to Zr doping as well as (Zr, Ni) co-doping in STO. The chemical species of the samples were identified using energy-dispersive X-ray spectroscopy. We observed forbidden first order Raman scattering at 148, 547 and 797 cm$^{-1}$ which may indicate nominal loss of inversion symmetry in cubic STO. The absence of absorption at 500 cm$^{-1}$ and within 600-700 cm$^{-1}$ band in Fourier Transform Infrared spectra corroborates Zr and Ni as substitutional dopants in our samples. Due to 4% Zr doping in $\text{Sr}_\text{0.96}\text{Zr}_\text{0.04}\text{Ti}\text{O}_3$ sample dielectric constant, remnant electric polarization, remnant magnetization and coercivity were increased. Notably, in the case of 4% Zr and 10% Ni co-doping we have observed clearly the existence of both FE and FM hysteresis loops in $\text{Sr}_{0.96}\text{Zr}_{0.04}\text{Ti}_{0.90}\text{Ni}_{0.10}\text{O}_3$ sample. In this co-doped sample, the remnant magnetization and coercivity were increased by $\sim$1 and $\sim$2 orders of magnitude respectively as compared to those of undoped STO. The coexistence of FE and FM orders in (Zr, Ni) co-doped STO might have the potential for interesting multiferroic applications.

cond-mat.mtrl-sci↗