No abstract

Photon absorption, charge separation and transportation, and charge-induced reactions at the active sites are the main crucial factors involved in the photoelectrochemical (PEC) water splitting. Herein, a combination of black phosphorus quantum dot (BPQD) sensitization and defect engineering strategies is employed to optimize the PEC performance of one-dimensional TiO2 nanotube array (NTA) photoanodes. The as-prepared TiO2–x /BP electrode exhibits a strong photocurrent density under simulated solar light irradiation, which is almost ∼3 times higher than that of bare TiO2. Specifically, the photocurrent increment of TiO2–x /BP is even larger than the sum of TiO2–x and TiO2/BP, verifying the synergistic effect of oxygen vacancies and BPQD sensitization. The maximum photoconversion efficiency of TiO2–x /BP is as high as 0.35%, while the value of TiO2 NTAs is calculated to be 0.13%. The results reveal that oxygen vacancies and BPQDs in the TiO2–x /BP composite not only facilitate the charge separation and transportation but also enhance the activity and quantity of reactive sites for water oxidation. The present strategy might open new routes to develop high-performance photoelectrodes for water splitting.

In this work, a novel zirconium-based metal–organic framework (MOF) composite material, UiO-(OH)2@RhB, has been solvothermally prepared with zirconyl chloride octahydrate, 2,5-dihydroxyterephthalic acid, and rhodamine B (RhB) for ratiometric fluorescence sensing of Al3+ ions in an aqueous medium. The luminescence measurement results showed that, at the single excitation wavelength of 420 nm, the fluorescence intensity of the ligand at 500 nm increased significantly in the case of Al3+, while that of RhB at 583 nm changed slightly, together with an apparent color change. Under optimal conditions, UiO-(OH)2@RhB exhibited an extraordinary sensitivity (10 nM), good selectivity, and a fast response (2 min) for Al3+. As far as we know, the limit of detection is superior to that of the current reported MOF-based Al3+ fluorescence sensors. The response mechanism suggested that −OH could capture Al3+ in water through coordination and high electrostatic affinity and achieved turn-on ratiometric fluorescence through the excited-state intramolecular proton transfer process and stable fluorescence of RhB. In addition, this sensor was also applied to actual food samples (grain beans), with the recoveries ranging from 89.08% to 113.61%. Such a turn-on ratiometric fluorescence sensor will provide a constructive strategy for the ultrasensitive detection of Al3+ in practical applications.

Coupling oxidative biomass valorization with H2 production in a hybrid water splitting configuration is of significant importance to yield sustainable and value-added carbon products. Herein, we report an earth-abundant alloy...

In order to satisfy the growing requirements of wearable electronic devices, 1D fiber‐shaped devices with outstanding sensitivity, flexibility, and stability are urgently needed. In this study, a novel inorganic‐organic heterojunction fibrous photodetector (FPD) based on poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and highly ordered TiO2 nanotube array is fabricated, which endows a high responsivity, large external quantum efficiency, and fast response speed at 3 V bias. To further ameliorate its performance in the self‐powered mode, a facile acid treatment is adopted and the assembled H‐PEDOT:PSS/TiO2 FPD demonstrates outstanding self‐powered properties with ≈3000% responsivity enhancement (161 mA W−1 at 0 V under 365 nm irradiation, photocurrent enhancement of ≈50 times) compared with the untreated device. It is found that the concentrated H2SO4 post‐treatment helps decrease the tube wall thickness of TiO2 and partially removes the insulated PSS component in PEDOT:PSS, leading to enhanced conductivity and facilitated charge transportation, and thereby superb responsivity/photocurrent enhancement of self‐powered H‐PEDOT:PSS/TiO2 FPD. This low‐cost and high‐performance self‐powered FPD shows high potential for applications in wearable electronic devices.