Facile Fabrication of Highly Stable and Wavelength-Tunable Tin Based Perovskite Materials with Enhanced Quantum Yield via the Cation Transformation Reaction.

Metal halide perovskites have attracted great attention for their superior light energy conversion applications. Herein, we demonstrated a facile synthesis of zero-dimensional Sn2+ perovskite Cs4-xMxSnBr6(M = K+ and Rb+) material through the cation transformation reaction at room temperature. Cs4SnBr6 NCs was mixed with pure metal bromide salts (KBr and RbBr) via the mechanochemical process to successfully synthesize Cs4-xMxSnBr6 perovskite where transformation of Cs to mixed Cs/Rb and mixed Cs/K was achieved. By substituting different cations, the bright fluorescence of the Cs4-xMxSnBr6 was tuned from dim green to greenish-cyan while achieving the photoluminescence (PL) quantum yield of ∼39%. The crystal structure of Sn based perovskite with the substitution of K+ or Rb+ cations was determined by X-ray diffraction (XRD). Moreover, the Cs4-xMxSnBr6 demonstrated superior air stability and exhibited a better photocatalytic activity for CO2 reduction reaction (CO2RR) with high selectivity of CH4 gas with a higher yield rate compared to the pristine Cs4SnBr6 NCs.

Electrocatalytic Reduction of NO3- to Ultrapure Ammonia on {200} Facet Dominant Cu Nanodendrites with High Conversion Faradaic Efficiency.

Nitrate (NO3-) reduction reaction (NtRR) is considered as a green alternative method for the conventional method of NH3 synthesis (Haber-Bosch process), which is known as a high energy consuming and large CO2 emitting process. Herein, the copper nanodendrites (Cu NDs) grown along with the {200} facet as an efficient NtRR catalyst have been successfully fabricated and investigated. It exhibited high Faradaic efficiency of 97% at low potential (-0.3 V vs RHE). Furthermore, the 15NO3- isotope labeling method was utilized to confirm the formation of NH3. Both experimental and theoretical studies showed that NtRR on the Cu metal nanostructure is a facet dependent process. Dissociation of NO bonding is supposed to be the rate-determining step as NtRR is a spontaneously reductive and protonation process for all the different facets of Cu. Density functional theory (DFT) calculations revealed that Cu{200} and Cu{220} offer lower activation energy for dissociation of NO compared to that of Cu{111}.

Challenges and prospects of polyatomic ions' intercalation in the graphite layer for energy storage applications.

Global population explosion has led to the rapid revolution of science and technology, and the high energy demand has necessitated new and efficient energy conversion and storage systems. Lithium ion batteries (LIBs) have a high potential window, high capacity, and high stability, but suffer from high cost and low safety. Therefore, many alternative batteries, including sodium ion batteries (NIBs), potassium (KIBs), aluminum (AIBs), and dual ion batteries (DIBs), have been introduced. One of the key working principles of these batteries is based on cation or anion intercalation in the graphite layers, and leads to the formation of graphite intercalation compounds (GICs). Recently, studies based on determining a reaction mechanism to improve the performance of the batteries have been conducted. In this review, an overview of the work on the reaction mechanism of polyatomic ions intercalated into GICs, the structure of intercalated polyatomic ions, the structure of the accommodated GICs, and their staging is provided. In other words, this review focuses on unraveling and understanding the reaction mechanisms for the intercalation of polyatomic ions into GICs by in situ and ex situ techniques, correlated with computational studies. The current limitations and future prospects of polyatomic ions intercalation batteries are also discussed.

Exploration and Investigation of Periodic Elements for Electrocatalytic Nitrogen Reduction.

High demand for green ecosystems has urged the human community to reconsider and revamp the traditional way of synthesis of several compounds. Ammonia (NH3 ) is one such compound whose applications have been extended from fertilizers to explosives and is still being synthesized using the high energy inhaling Haber-Bosch process. Carbon free electrocatalytic nitrogen reduction reaction (NRR) is considered as a potential replacement for the Haber-Bosch method. However, it has few limitations such as low N2 adsorption, selectivity (competitive HER reactions), low yield rate etc. Since it is at the early stage, tremendous efforts have been devoted in understanding the reaction mechanism and screening of the electrocatalysts and electrolytes. In this review, the electrocatalysts are classified based on the periodic table with heat maps of Faraday efficiency and yield rate of NH3 in NRR and their electrocatalytic properties toward NRR are discussed. Also, the activity of each element is discussed and short tables and concise graphs are provided to enable the researchers to understand recent progress on each element. At the end, a perspective is provided on countering the current challenges in NRR. This review may act as handbook for basic NRR understandings, recent progress in NRR, and the design and development of advanced electrocatalysts and systems.

A Quinone-Based Electrode for High-Performance Rechargeable Aluminum-Ion Batteries with a Low-Cost AlCl3/Urea Ionic Liquid Electrolyte.

Intensive energy demand urges state-of-the-art rechargeable batteries. Rechargeable aluminum-ion batteries (AIBs) are promising candidates with suitable cathode materials. Owing to high abundance of carbon, hydrogen, and oxygen and rich chemistry of organics (structural diversity and flexibility), small organic molecules are good choices as the electrode materials for AIB. Herein, a series of small-molecule quinone derivatives (SMQD) as cathode materials for AIB were investigated. Nonetheless, dissolution of small organic molecules into liquid electrolytes remains a fundamental challenge. To nullify the dissolution problem effectively, 1,4-benzoquinone was integrated with four bulky phthalimide groups to form 2,3,5,6-tetraphthalimido-1,4-benzoquinone (TPB) as the cathode materials and assembled to be the AI/TPB cell. As a result, the Al/TPB cell delivered capacity as high as 175 mA h/g over 250 cycles in the urea electrolyte system. Theoretical studies have also been carried out to reveal and understand the storage mechanism of the TPB electrode.

Real-Time Observation of Anion Reaction in High Performance Al Ion Batteries.

Recently, aluminum ion batteries (AIBs) have attracted great attention across the globe by virtue of their massive gravimetric and volumetric capacities in addition to their high abundance. Though carbon derivatives are excellent cathodes for AIBs, there is much room for further development. In this study, flexuous graphite (FG) was synthesized by a simple thermal shock treatment, and for the first time, an Al/FG battery was applied as a cathode for AIBs to reveal the real-time intercalation of AlCl4- into FG with high flexibility by using in-situ scanning electron microscope (SEM) measurements exclusively. Similarly, in-situ X-ray diffraction (XRD) and in-situ Raman techniques have been used to understand the anomalous electrochemical behavior of FG. It was found that FG adopts a unique integrated intercalation-adsorption mechanism where it follows an intercalation mechanism potential above 1.5 V and an adsorption mechanism potential below 1.5 V. This unique integrated intercalation-adsorption mechanism allows FG to exhibit superior properties, like high capacity (≥140 mAh/g), remarkable long-term stability (over 8000 cycles), excellent rate retention (93 mAh/g at 7.5 A/g), and extremely rapid charging and slow discharging.

Self-medication practice and perceptions among undergraduate medical students: a cross-sectional study.

BACKGROUND: Self-medication practice is widespread in many countries and the irrational use of drugs is a cause of concern.It assumes a special significance among medical students as they are exposed to knowledge about diseases and drugs. AIM: To assess practice and perception of self medication among undergraduate medical students. MATERIALS AND METHODS: It is a cross-sectional study in which study population consisted of undergraduate medical students of Mahadevappa Rampure Medical College Gulbarga, Karnataka, India. This study was conducted from March to April 2014. Total 448 students were taken. Out of which 8 incomplete questionnaires were excluded and 440 were analysed. The students who took self-medication during last six months were included. Written informed consent was obtained from each volunteer prior to the study. Students were given a questionnaire that include both open and close ended questions about self-medication practice. Ethical Approval: Ethics Committee approval was obtained from the Institutional Ethics Committee of Mahadevappa Rampure Medical College, Gulbarga, India, prior to the commencement of the study. STATISTICAL ANALYSIS: Data was analysed and presented as counts and percentages. RESULTS: It was found that 388 (88.18%) students practiced self medication. The principal morbidity for seeking self medication was cold and cough as reported by 304 (78.35%) students. Antibiotics were most commonly self medicated as reported by 248 (63.91%) students, out of which only 92 (37.1%) students completed the full course of antibiotic regimen. Only 176 (40%) students opined that self medication is part of self care. CONCLUSION: Self-medication is widely practiced among undergraduate medical students. In this situation, we should educate the students about advantages and disadvantages of self medication.