Raja Peary Mohan College

Cerium dioxide (CeO2) remains a cornerstone of heterogeneous catalysis due to its reversible Ce4+/Ce3+ redox chemistry and dynamic oxygen exchange. This review establishes a unified defect-facet-redox coupling framework, demonstrating that catalytic performance is governed by the interplay between oxygen vacancy formation, migration, and surface accessibility rather than isolated descriptors such as equilibrium OSC. Integrating insights from DFT, operando spectroscopy, and advanced characterization, we identify dynamic oxygen storage capacity (DOSC) and vacancy mobility as key predictors of reactivity under realistic conditions. Facet-dependent reducibility and metal-support interactions are shown to control adsorption pathways and catalytic selectivity across gaseous pollutant abatement, wastewater treatment, and CO2 conversion. Emerging directions in high-entropy oxides and single-atom catalysts further highlight strategies for precise defect and interface engineering, while challenges in stability, scalability, and descriptor standardization remain critical for practical deployment.

Two diorganotin(IV) complexes of the general formula[R2Sn{Ph(O)C=CH-C(Me)=N-C6H3(2-O)(4-NO2)}] [R2Sn (HNPP)] (R = Ph, 1a; R = Me, 1b) have been synthesized from the corresponding diorganotin(IV) dichlorides and the ligand, 3-((2-hydroxy-4-nitrophenyl)imino)-1-phenylbutan-1-one, H2HNPP (1) in methanol at room temperature in presence of triethylamine. Both compounds have been characterized by elemental analyses, IR and 1H, 13C, 119Sn NMR spectra. The structures of the free ligand and the complexes have been confirmed by single crystal X-ray diffraction. There are two independent molecules in the crystal structure of the ligand 1 and the O-bound proton in imino-en-ol form (II) of the ligand is not transferred to the imine nitrogen as compared to the ligand, 3-(2-hydroxyphenylimino)-1-phenylbutan-1-one (H2HPP) in which O-bound proton is transferred to the imine nitrogen. The X-ray structure of the ligand, H2HNPP (1) shows that it exists exclusively in keto form in solid state but it exists as enol form in solution as evident from solution state NMR spectrum. It reacts with diorganotin(IV) dichlorides in solution as enol form. In both 1a and 1b, the central tin atom adopts distorted trigonal-bipyramidal coordination geometry. The dimethyltin(IV) compound (1b) derived from H2HNPP (1) is not dimeric whereas dimethyltin(IV) compound derived from H2HPP was dimeric. This may be due to presence of-NO2 group in 1, which makes phenolic-O less basic. The delta(119Sn) values for the complexes 1a and 1b are-301.7 and-124.1 ppm, respectively, thus indicating penta-coordinated Sn centres in solution.

Galactic centres are highly dynamic regions dominated by a supermassive black hole (BH) surrounded by nuclear star clusters (NSC), molecular gas, and asymmetric matter distributions such as disks or halos. The combined gravitational effects of these components, along with relativistic corrections from the BH's spin, generate strongly nonlinear dynamics and frequent chaotic orbital behaviour. To model this environment, we employ a multipolar expansion potential in which the central compact object is represented by the Artemova-Bjornsson-Novikov pseudo-Newtonian potential, effectively capturing spin-dependent features of a Kerr-like BH. The surrounding halo is treated as an axisymmetric, shell-like mass distribution expanded up to third order in multipolar terms to account for realistic asymmetry. Previous studies have mainly explored the influence of multipolar moments and BH spin using Poincare sections, SALI, and related chaos indicators. In this work, we extend these analyses by incorporating stability analysis and basins of convergence to achieve a more complete understanding of the system's dynamics. Stability analysis around equilibrium points provides insight into local behavior, while basins of convergence highlight sensitivity to initial conditions and expose fractal basin boundaries. Our results show that the BH spin significantly reshapes phase space: depending on its magnitude and orientation, it can either amplify chaotic scattering caused by halo asymmetry or stabilize specific orbital families. These findings enhance our understanding of how relativistic spin effects and multipolar mass distributions jointly govern the dynamical architecture of galactic centers.

Maneuvering the growing requirement of advanced energy storage materials, we introduce the synthesis of undoped and ruthenium-doped molybdenum disulfides (MoS2) with precisely controlled ruthenium (Ru) concentrations of 2%, 5%, and 10%, achieved through a one-step hydrothermal method. The structural properties of these compounds are meticulously examined using a suite of advanced techniques, including X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). Electrochemical studies demonstrate that the 5% Ru-doped compound outperforms both the undoped sample and other Ru-doped variants. In a three-electrode configuration, the 5% Ru-doped compound exhibits a specific capacitance of 489 F g-1 at 1 mV s-1 from cyclic voltammetry (CV) measurement and 287 F g-1 at 1 A g-1 from galvanostatic charge-discharge (GCD) measurement. Moreover, the 5% Ru-doped compound exhibits an extended potential window of 2 V, an impressive specific energy of 42 Wh kg-1 at 1 A g-1, and a remarkable specific power of 8 kW kg-1 at 10 A g-1 in a symmetric supercapacitor configuration. Electrochemical impedance spectroscopy reveals that ruthenium doping enhances electrical conductivity, while stability analysis confirms exceptional cycling stability, with 99.71% capacitance retention over 5000 cycles. These findings suggest that the synthesized compound is a promising candidate for next-generation energy storage applications, including electric vehicles, wearable devices, and other advanced technologies.