Unveiling efficient S-scheme charge carrier transfer in hierarchical BiOBr/TiO2 heterojunction photocatalysts.

The construction of a potential heterojunction catalyst with proper interface alignment has become a hot topic in the scientific community to effectively utilize solar energy. In this work, a one-dimensional TiO2 nanofiber/BiOBr S-scheme heterojunction was synthesized, and charge carrier dynamics within the interface channel were explored. In addition, we incorporated mixed phase TiO2 with point defects and oxygen vacancies, which greatly promoted the initial band edge shift from the UV region. Upon the addition of BiOBr, absorption in the visible light region of the electromagnetic (EM) spectrum was observed with a decrease in the optical band gap value. The optimized BiOBr heterojunction (BTNF1.5) revealed a higher photocatalytic RhB dye degradation efficiency due to the efficient generation and separation of charge carriers upon light irradiation. The optimum sample BTNF1.5 showed a high degradation efficiency of 98.4% with a rate constant of 47.1 min-1 at 8 min of visible light irradiation, which is double than that of the pure TiO2. Electrochemical analysis, time-resolved photoluminescence and Kelvin probe measurement revealed an S-scheme charge-transfer mechanism within the BiOBr/TiO2 system. This work provides a strategy for the facile synthesis of heterojunction photocatalysts exhibiting exceptional catalytic performance.

Pyrene Derivative Incorporated Ni MOF as an Enzyme Mimic for Noninvasive Salivary Glucose Detection Toward Diagnosis of Diabetes Mellitus.

Herein, we demonstrate the detection of glucose in a noninvasive and nonenzymatic manner by utilizing an extended gate field-effect transistor (EGFET) based on the organic molecule pyrene phosphonic acid (PyP4OH8) incorporated nickel metal-organic framework (NiOM-MOF). The prepared electrode responds selectively to glucose instead of sucrose, fructose, maltose, ascorbic acid, and uric acid in a 1× phosphate buffer saline solution. Also, utilizing the scanning Kelvin probe system, the sensing electrode's work function (Φ) is measured to validate the glucose-sensing mechanism. The sensitivity, detection range, response time, limit of detection, and limit of quantification of the electrode are determined to be 24.5 µA mM-1 cm-2, 20 µM to 10 mM, less than 5 s, 2.73 µM, and 8.27 µM, respectively. Most interestingly, the developed electrode follows the Michaelis-Menten kinetics, and the calculated rate constant (km) 0.07 mM indicates a higher affinity of NiOM-MOF toward glucose. The real-time analysis has revealed that the prepared electrode is sensitive to detect glucose in real human saliva, and it can be an alternative device for the noninvasive detection of glucose. Overall, the outcomes of the EGFET studies demonstrate that the prepared electrodes are well-suited for expeditious detection of glucose levels in saliva.