Novel Ag-bridged dual Z-scheme g-C3N4/BiOI/AgI plasmonic heterojunction: Exceptional photocatalytic activity towards tetracycline and the mechanism insight

Construction of a BiOI/ZnO heterojunction on biomass Juncus effusus fiber for photodegradation of organic pollutants

Semiconductor heterojunction engineering and three-dimensional (3D) architecture construction have been considered highly desirable strategies to enhance photocatalytic performance. Herein, a BiOI/ZnO composite photocatalyst with a 3D flower-like architecture was successfully prepared, which was stably immobilized on three-dimensional porous lignocellulosic biomass Juncus effusus (JE) fiber. The outstanding photocatalytic performance of the BiOI/ZnO-JE fiber was confirmed by the degradation of tetracycline hydrochloride (TC, 90%), ciprofloxacin (CIP, 79%), and norfloxacin (NOR, 81%). The enhanced photocatalytic activities were mainly attributed to the synergistic absorption performance of the lignocellulosic JE and the effective transfer and separation of charges. Moreover, the hydroxyl (·OH) and superoxide radicals (·O2-) are the main reactive species in the photocatalytic process according to the analysis. This work may provide a novel perspective for constructing high-performance lignocellulosic-based photocatalytic materials.

A novel photoelectrochemical aptasensor based on 3D flower-like g-C3N4/BiOI p-n heterojunction for the sensitive detection of kanamycin

BACKGROUND

Kanamycin (KAN) residues in animal-derived foods continuously enter the human body, which will pose serious threats to human health such as hearing loss, nephrotoxicity and other complications. Therefore, to sensitively detect KAN residues by a reliable technology is extremely urgent in food quality and safety. Compared with traditional methods being limited by cost and complexity, photoelectrochemical (PEC) biosensors benefit from some merits such as rapid response, excellent sensitivity and good stability. In this study, the construction of a highly efficient PEC platform to realize KAN residues detection is discussed.

RESULTS

Herein, a novel p-n heterojunction consisting of flower-like BiOI microspheres and graphite carbon nitride (g-C3N4) nanoflakes was developed to establish a PEC aptasensor for KAN detection at 0 V. The prepared g-C3N4/BiOI heterostructure showed not only significantly enhanced PEC activity due to the larger specific surface area but also greatly increased charge separation efficiency owing to the strong internal electric field. Meanwhile, using g-C3N4/BiOI as a highly efficient photoactive material for binding amine-functionalized aptamers to capture KAN, the photocurrent signals showed a 'turn off' mode to achieve the sensitive detection of KAN. The proposed PEC aptasensor exhibited linear response for KAN from 5 × 10-9 to 3 × 10-7 mol L-1 with a low detection limit of 1.31 × 10-9 mol L-1, and satisfactory recoveries (97.44-107.38 %) were obtained in real food samples analysis.

SIGNIFICANCE

This work presented a novel p-n heterojunction-based PEC aptasensor with strong selectivity and stability, rendering it allowed to detect KAN in animal-derived foods including milk, honey and pork. Additionally, the detection range satisfied the MRLs for KAN specified by the national standards, demonstrating the potential application for food analysis. The study provides a new insight into the development of efficient and practical biosensors for antibiotic residues detection.

Non-radical activation of persulfate with Bi2O3/BiO1.3I0.4 for efficient degradation of propranolol under visible light

Non-radical activation of persulfate (PS) by photocatalysts is an effective approach for removing organic pollutants from aqueous environments. In this study, a novel Bi2O3/BiO1.3I0.4 heterojunction was synthesized using a facile solvothermal approach and used for the first time for non-radical activation of PS to degrade propranolol (PRO) in the presence of visible light. The findings found that the degradation rate of PRO in the Bi2O3/BiO1.3I0.4/PS system was significantly increased from 19% to more than 90% within 90 min compared to the Bi2O3/BiO1.3I0.4 system. This indicated that the composite system exerted an excellent synergistic effect between the photocatalyst and the persulfate-based oxygenation. Quenching tests and electron paramagnetic resonance demonstrated that the non-radical pathway with singlet oxygen as the active species played a major role in the photocatalytic process. The existence of photo-generated holes during the reaction could also be directly involved in the oxidation of pollutants. Meanwhile, a possible PRO degradation pathway was also proposed. Furthermore, the impacts of pH, humic acid and common anions on the PRO degradation by the Bi2O3/BiO1.3I0.4/PS were explored, and the system's stability and reusability were also studied. This study exhibits a highly productive catalyst for PS activation via a non-radical pathway and provides a new idea for the degradation of PRO.

Unveiling the potential of a BCN-biphenylene monolayer as a high-performance anode material for alkali metal ion batteries: a first-principles study

Inspired by a freshly synthesized two-dimensional biphenylene carbon network, which features a captivating combination of hexagonal, square, and octagonal rings, we explored a similar biphenylene network composed of boron, carbon, and nitrogen (bpn-BCN) using first-principles calculations. There are six possible phases of borocarbonitrides, which are isoelectronic to biphenylene carbon networks with a stoichiometric ratio of 1 : 1 : 1 for boron (B), carbon (C), and nitrogen (N) atoms. All possible isoelectronic structures of the BCN combination of biphenylene networks are found to be stable, according to first-principles calculations. However, the geometry has a relatively large number of robust C-C and B-N bonds and strong partially ionic-covalent B-C and C-N bonds inside these bpn-BCN monolayers are effectively more stable. Furthermore, we employed first-principles calculations to investigate the electrochemical properties of the most stable geometry of BCN biphenylene as a potential anode material for alkali metal (AM) ion batteries. A global search has been made to find the most favourable alkali metal ion adsorption sites. The biphenylene monolayer has octagonal, square, and hexagonal motifs with different adsorption strengths. Furthermore, the partially ionic bond of B-N (due to the electronegativity difference) also supports the alkali metal ions for adsorption. The electronic properties of the stable phase of bpn-BCN reveal its narrow bandgap semiconductor nature. The ion diffusion calculations show a low activation barrier for Li, Na, and K of 0.65 eV, 0.26 eV, and 0.23 eV, respectively, indicating a fast charge/discharge rate. Furthermore, the theoretical capacities of the BCN biphenylene monolayer for Li (1057.33 mA h g-1), Na (647.27 mA h g-1), and K (465.98 mA h g-1) are found to be greater than those of commercial graphite. The average open-circuit voltage for AM decreases with increasing metal ion concentrations. It falls within a reasonable range of 0.34-1.89 V. Our results show that the BCN biphenylene monolayer could be a promising anode material in alkali metal ion rechargeable batteries.

Construction of novel Ag/AgI/Bi4Ti3O12 plasmonic heterojunction: A study focusing on the performance and mechanism of photocatalytic removal of tetracycline

As a result of the insufficient absorption of visible light, the application of Bi4Ti3O12 in the field of photocatalysis is limited. Ag/AgI was uniformly modified on the surface of the nanoflower bulb of Bi4Ti3O12 by simple precipitation method and photodeposition. The fabricated Ag/AgI/Bi4Ti3O12 obtained an ultra-high tetracycline (TC) removal rate under visible light irradiation. And the synergetic effects caused by the surface plasmon resonance (SPR) effect of Ag, the photosensitivity of AgI and the p-n heterojunction are the key to improving the photocatalytic performance of materials. Besides, four plausible photodegradation pathways of TC were proposed and its intermediates were evaluated for toxicity, showing a significant decrease in toxicity after photoreaction.

Sonochemically assisted the synthesis and catalytic application of bismuth-based photocatalyst: A mini review

Recently, bismuth (Bi)-based photocatalysts have been a well-deserved hotspot in the field of photocatalysis owning to their photoelectrochemical properties driven by the distortion of the Bi 6 s orbital, while their narrow band gap and poor quantum efficiency still restrict their application. With the development of ultrasonic technology, it is expected to become a broom to clear the application obstacles of Bi-based photocatalysts. The special forces and environmental conditions brought by ultrasonic irradiation play beneficial roles in the preparation, modification and performance releasement of Bi-based photocatalysts. In this review, the role and influencing factors of ultrasound in the preparation and modification of Bi-based photocatalysts were introduced. Crucially, the mechanism of the improving the performance for various types of Bi-based photocatalysts by ultrasound in the whole process of photocatalysis was deeply analyzed. Then, the application of ultrasonic synergistic Bi-based photocatalysts in contaminants treatment and energy conversion was briefly introduced. Finally, based on an unambiguous understanding of ultrasonic technology in assisting Bi-based photocatalysts, the future directions and possibilities for ultrasonic synergistic Bi-based photocatalysts are explored.