ABSTRACT
Metal-organic frameworks (MOFs) and MXenes have gained prominence in the queue of advanced material research. Both materials' outstanding physical and chemical characteristics prominently promote their utilization in diverse fields, especially the electrochemical energy storage (EES) domain. The collective contribution of extremely high specific surface area (SSA), customizable pores, and abundant active sites propose MOFs as integral materials for EES devices. However, conventional MOFs endure low conductivity, constraining their utility in practical applications. The development of hybrid materials via integrating MOFs with various conductive materials stands out as an effective approach to improvising MOF's conductivity. MXenes, formulated as two-dimensional (2D) carbides and nitrides of transition metals, fall in the category of the latest 2D materials. MXenes possess extensive structural diversity, impressive conductivity, and rich surface chemical characteristics. The electrochemical characteristics of MOF@MXene hybrids outperform MOFs and MXenes individually, credited to the synergistic effect of both components. Additionally, the MOF derivatives coupled with MXene, exhibiting unique morphologies, demonstrate outstanding electrochemical performance. The important attributes of MOF@MXene hybrids, including the various synthesis protocols, have been summarized in this review. This review delves into the architectural analysis of both MOFs and MXenes, along with their advanced hybrids. Furthermore, the comprehensive survey of the latest advancements in MOF@MXene hybrids as electroactive material for supercapacitors (SCs) is the prime objective of this review. The review concludes with an elaborate discussion of the current challenges faced and the future outlooks for optimizing MOF@MXene composites.
ABSTRACT
The electrical conductivity of Na2O substituted zinc borate glasses has been studied in the frequency range of 10 mHz to 1 MHz and in the temperature range from 313 to 573 K. The conduction mechanism has been ascertained using the values of the frequency exponent (s) extracted from the fitting of experimental data of the real part of electric conductivity in light of the Almond-West equation. Depending on the glass composition, the ac conduction in the glasses happened via correlated barrier hopping and non-overlapping small polaron tunneling conduction models. The electric modulus studies support the assertion of composition dependent conduction mechanisms. Furthermore, electronic conduction and ionic conduction have been studied from impedance investigations. Equivalent circuit models were used to fit the Nyquist and Bode plots of each sample at the temperatures under consideration. It has been found that the activation energy values calculated from conductivity, electric modulus, and impedance measurements are more or less the same.
ABSTRACT
A series of Ce3+ doped La1-xCexAlO3/MgO (x = 0, 0.7, 0.9, 1.0 and 2.0 mol%) nano-composites have successfully been synthesized employing the Pechini sol-gel method. XRD profiles assisted with Rietveld refinement results manifested the rhombohedral/face-centered structures of the two phases of the generated composite. Thermogravimetric results corroborate the crystallization temperature of the compound to be 900 °C, that further remains stable up to 1200 °C. Materials have been found to be wide band gap semi-conductors having Eg in the range of 5.5-5.8 eV. Photoluminescence studies reveal their green emission under UV excitation of 272 nm. Application of Dexter's theory and Burshtein model to PL and TRPL profiles, respectively reveals the q-q multipole interlinkages to be the viable cause of concentration quenching beyond optimum concentration of 0.9 mol%. Shifting of the energy transfer route from cross-relaxation to migration assisted mechanism with Ce3+ concentration has also been investigated. Other luminescence based parameters such as energy transfer probabilities, efficiencies, CIE and CCT have also been found to be in an admirable range. From the aforesaid results, it was observed that the optimized nano-composite (i.e. La1-xCexAlO3/MgO (x = 0.9 mol%)) can also be utilized for latent finger-printing (LFP) application that evinces its versatility for photonic as well as imaging applications.
ABSTRACT
BACKGROUND: Chronic otitis media (COM) remains a major public health issue and is associated with relentless discharge from the ear, pain, significant functional limitation of hearing, leading to communication problems and frequent specialist visits. AIMS: To assess the improvement in quality of life of patients of COM (safe type) and surgical success in terms of graft uptake and improvement in hearing. PATIENTS AND METHODS: A prospective questionnaire-based outcome study was directed in 100 patients with COM who were treated with Type I Tympanoplasty at our institution between May 2018 and May 2020. All patients were asked to fill Modified Chronic Otitis Media 4 (COM-4) survey before operation and 3 months after operation. Preoperative and postoperative total ear scores, audiological results, postoperative graft uptake were assessed. RESULTS: The correlation between preoperative and postoperative assessment by questionnaire was statistically critical (P < 0.001). There was significant improvement in hearing postoperatively (P < 0.001). Effective graft uptake was seen in 80%. CONCLUSION: The current study emphasizes that Type 1 Tympanoplasty fundamentally improves quality of life of patients in terms of physical suffering, hearing loss, emotional distress postoperatively.