P=O Functionalized Black Phosphorus/1T-WS2 Nanocomposite High Efficiency Hybrid Photocatalyst for Air/Water Pollutant Degradation

Chlorine-functionalized black phosphorus quantum dots induced superoxide anion generation and depletion for efficient chemiluminescence detection

BACKGROUND

Due to their unique optoelectronic properties, environmental friendliness, and excellent biocompatibility, metal-free quantum dots have been a new star in exploring novel chemiluminescence (CL) systems for analytical applications in recent years. However, unknown CL property, relatively weak emission and instability of some of them in water (eg. black phosphorus) often seriously hindered their further applications. Hence, developing a novel QDs-assist CL signal amplification to achieve efficient analyst detection is significant and currently hot topic for researchers.

RESULTS

In this work, we purposely synthesized chlorine-functionalized black phosphorus quantum dots (Cl-BPQDs) with improved stability and rich-hole property, which were demonstrated to exhibit the excellent capability for the activation of ferrate (VI) with large reactive oxygen species generation and leading to enhanced CL signal. The detail mechanism was demonstrated, the unique CL response to the presence of active sites (P-Cl) in Cl-BPQDs, which accelerated ferrate (VI) decomposition and produced a large amount of superoxide anion (•O2-). And then, the radiative recombination of the exogenous electron-donated and existing holes Cl-BPQDs accounting for the strong CL emission. Furthermore, based on the consumption capacity of ascorbic acid (AA) and glutathione (GSH) for •O2-, a direct CL sensing platform of Cl-BPQDs/ferrate (VI) quenching was fabricated to AA and GSH detection. This fabricated assay has broad detection linear ranges (2-200 μM) and low detection limit (GSH: 1.3 μM; AA: 1.7 μM). Compared with the reported CL technique, this new method displayed superior sensitivity and anti-interference capabilities toward transition-metal ions and inorganic anions. The potential analytical application of the new CL system was further demonstrated by the evaluation of total antioxidant capacity (TAC) in diabetic patients.

SIGNIFICANCE

This study proposes a new strategy for enhancing CL signal via Cl-BPQDs triggering •O2- generation and depletion, which provides an innovative tool for ascorbic acid and glutathione detection. This method not only enriches our understanding of the optical characteristics of BP, but also provides a new charge transfer-based path for CL amplification.

Recent Progress on Synthesis and Properties of Black Phosphorus and Phosphorene As New-Age Nanomaterials for Water Decontamination

Concerted efforts have been made in recent years to find solutions to water and wastewater treatment challenges and eliminate the difficulties associated with treatment methods. Various techniques are used to ensure the recycling and reuse of water resources. Owing to their excellent chemical, physical, and biological properties, nanomaterials play an important role when integrated into water/wastewater treatment technologies. Black phosphorus (BP) is a potential nanomaterial candidate for water and wastewater treatment, especially its monolayer 2D derivative called phosphorene. Phosphorene offers relative adjustability in its direct bandgap, high charge carrier mobility, and improved in-plane anisotropy compared to the most extensively studied 2D nanomaterials. In this study, we examined the physical and chemical characteristics and synthetic processes of BP and phosphorene. We provide an overview of the latest advancements in the main applications of BP and phosphorene in water/wastewater treatment, which are categorized as photocatalytic, adsorption, and membrane filtration processes. Additionally, we explore the existing difficulties in the integration of BP and phosphorene into water/wastewater treatment technologies and prospects for future research in this field. In summary, this review highlights the ongoing necessity for significant research efforts on the integration of BP and phosphorene in water and wastewater applications.

Linker-free Functionalization of Phosphorene Nanosheets by Sialic Acid Biomolecules

The importance of sialic acid on cell functions has been recently unveiled, and consequently, great attention has been paid to its interaction with tumor cells. In this line of research, we have realized phosphorene nanosheets functionalized with sialic acid molecules for biological applications with no need for another linker molecule. The formation of phosphorene sheets is feasible by using hydrogen plasma treatment and conversion of amorphous phosphorus on silicon substrates into highly crystalline nanosheets. Through immersion of these freshly prepared nanosheets into an aqueous solution containing sialic acid molecules, the formation of chemical binding between biomolecules and P atoms is initiated to form a carpet-like coverage. We have studied these structures by using Raman spectroscopy, electron microscopy, FTIR-ATR spectroscopy, and X-ray photoelectron spectroscopy. While XPS supports the passivation of sialic-activated phosphorene nanosheets (SAP) against oxidation in air or aqueous solutions, the FTIR analysis corroborates the evolution of P-O-C and P-C bonds between such biomolecules and the sheet surface. Moreover, the high-resolution TEM images demonstrate a considerable reduction in the lattice spacing from 0.32 nm for pristine phosphorene to 0.30 nm. Similarly, Raman spectroscopy depicts a shift in A2g in-plane vibrations, owing to the evolution of stress in the passivated sheets. To investigate their biocompatibility, we examined the toxicity of these bioactivated structures and observed no or little sign of toxicity. For the latter evaluation, we exploited MTT, flow cytometry, and animal models for in vivo investigations.

Accelerating the environmental applications of black phosphorus: A review

Since its rediscovery in 2014, layered black phosphorus (BP) has received extensive attention as a new two-dimensional semiconductor. BP is a promising material with properties of a large surface-to-volume ratio, wide light absorption range, tunable band gap, and high charge carrier mobility. These unique characteristics of BP make it a promising contender for various applications, particularly in the realm of environmental applications. This literature review provides a comprehensive discussion and overview of the latest developments in utilizing BP for environmental purposes. The review starts with the applications of BP in photocatalysis including photodegradation of refractory pollutants, H2 evolution reaction (HER), and reduction of CO2 and N2. In the following section, Environmental electrocatalysis of HER and N2 reduction reaction (NRR) is discussed. In addition, BP-based environmental sensing (detection of heavy metal ions, antibiotics, mycotoxins, NOx) and eco-friendly halogen-free flame retardant are summarized as well. Finally, a thorough comprehension of the current state and potential future trends of BP-based nanomaterials for various environmental applications are presented.