Electrochemical technologies like supercapacitors and water-splitting electrolysis are gaining traction due to their impressive efficiency in both energy storage and generation. A hydrothermal technique was employed to synthesize a metal–organic framework (MOF) containing zinc and nickel. Glycolic acid (GA), a naturally occurring biodegradable ligand, was utilized to explore its potential for incorporation into the MOF heterostructure. The ZnNi-MOF (GA) composites showed a notable specific capacity of 1648 C g⁻¹ (2060 F/g) under a current density of 1.0 A g⁻¹ at 70 °C. The study investigated a supercapacitor system design where a combination of polyaniline-doped activated carbon was used for the negative electrode and a zinc-nickel metal–organic framework (GA) was used for the positive electrode. The synthesized ZnNi-MOF (GA)//AC energy storage device demonstrated a specific capacity of 110 C g⁻¹ (55 F g⁻¹) at a higher current density of 2.0 A g⁻¹. The recyclability and stability of device (ZnNi-MOF (GA)//AC) were evaluated using 10000 charge–discharge cycles, yielding an 86% capacity retention. The ZnNi-MOF (GA) composite displayed outstanding catalytic ability in the hydrogen evolution reaction (HER) in comparison to other tested materials, achieving the lowest Tafel slope of 42.79 mV/dec. The findings of our research suggest that ZnNi-MOF (GA) exhibits desirable characteristics that make it a promising material for electrodes in the applications of supercapattery and HER.

Electronic, optical, and magnetic properties of the Mn-doped PbTiO₃ compound were investigated by using density functional theory (DFT). We revealed that this compound has an indirect band gap of 3.01 eV. The calculated complex dielectric functions were in good agreement with the available experimental results. Our calculation demonstrated that Mn substitution changes the nonspin-polarized state of pure PbTiO₃ to the spin-polarized state. O and Pb vacancies do not exhibit magnetism. However, Ti vacancies cause magnetism in the crystal, and the calculated magnetic moment was 1.68 µB.

The results of ab initio calculations of the electron spectrum of TlFeS₂ and TlFeSe₂ crystals in the antiferromagnetic phase are reported. Calculations are carried out in the context of the density functional theory. The origin of the bands of s, p, and d electron states of Tl, Fe, S, and Se atoms is studied. It is established that, in the antiferromagnetic phase, the crystals possess semiconductor properties. The band gaps are found to be 0.05 and 0.34 eV for TlFeS₂ and TlFeSe₂ crystals, respectively.