Functionalization Of Black Phosphorus Research Articles

Polyelectrolyte modified black phosphorus/titania nanosheet heterojunction enhanced photocatalysis: Synergistic enhancement effect of interface affinity and electron transport channel

The instability and high electron-hole recombination have limited the application of black phosphorus (BP) as an excellent photocatalyst. To address these challenges, poly dimethyl diallyl ammonium chloride (PDDA), poly (allylamine hydrochloride) (PAH), and polyethyleneimine (PEI) are introduced to the functionalization of BP (F-BP), which can not only enhance its stability, but also boost the carrier transfer. Furthermore, a high-performance heterojunction photocatalyst is fabricated using F-BP and titania nanosheets (TNs) via a layer-by-layer self-assembly approach. The experimental outcomes unequivocally indicate that F-BP exhibits fast charge migration compared to BP. The density functional theory (DFT), in situ Kelvin-probe force microscopy (KPFM) and other advanced characterization techniques collectively unfold that PDDA modified BP can notably boost separation and propagation of charges, along with an enhanced carrier abundance. In summary, this novel strategy of using polyelectrolytes to enhance the electron transfer and the stability of BP permits immense potential in building next-generation BP-based high efficiency photocatalysts.

Simultaneous exfoliation and functionalization of black phosphorus by sucrose-assisted ball milling with NMP intercalating and preparation of flame retardant polyvinyl alcohol film

Recently, layered black phosphorus (BP) has become a rising star in two-dimensional materials because of high thermal stability, excellent mechanical properties, and size effect. Layered BP can be used as an ideal filler for the preparation of polymer-based composites with high performance. Realizing the exfoliation and functionalization of BP has become the key to BP's application. Under the protection of N-methylpyrrolidone (NMP) and the assistance of sucrose, we completed the preparation and functionalization of layered BP by ball milling. Surface grafting of oxygen-containing functional groups can realize the uniform dispersion of BP in matrix and improve its stability in air. As expected, the nanocomposites prepared by adding sucrose grafted BP into polyvinyl alcohol (PVA) matrix have significantly improved flame retardancy and mechanical strength. When the addition amount of BP-sucrose(N) was 5 wt%, compared with pure PVA, the decrease of the peak heat release rate (PHRR) and total heat release (THR) reached 52.5% and 32.8%, and the tensile strength increased by 131.2%. Moreover, the addition of NMP can avoid the excessive destruction of the two-dimensional crystal structure of BP, which can also improve the performance of nanocomposites. Due to the encapsulation effect of sucrose, the nanocomposites have excellent air stability. The Ag1/Ag2 value only decreases from 0.52 to 0.49 even after three months of exposure to environmental conditions, which proves that the degree of oxidation is low. This work has provided an efficient way to exfoliate and functionalize BP simultaneously, and expanded the application of BP in flame retardant nanocomposites.

Facile preparation of self-assembled black phosphorus-based composite LB films as new chemical gas sensors

In recent years, the researches on the modification and functionalization of black phosphorus (BP) materials have attracted more and more attention. In this study, few-layers BP nanosheets (BPNS) were prepared by a simple liquid exfoliation method. However, BPNS has the disadvantages of easy oxidation and poor stability, which will also affect the performance of BP. Therefore, 4-azidobenzoic acid was used to modify the BPNS to improve the stability of BP. In addition, 4-azidobenzoic acid modified BPNS (f-BPNS) and dye molecules can form a composite Langmuir-Blodgett (LB) film through electrostatic interaction or π-π stacking forces. UV–vis, Atomic force microscopy (AFM) and other characterizations were used to prove the successful preparation of the f-BPNS-dye composite LB film. It should be noted that the obtained uniform and dense composite films showed good sensitivity to acid and alkali gas. Moreover, the f-BPNS-dye composite films can still maintain high performance after 10 cycles of acid-alkali tests, indicating that the prepared films have high stability. This work provides a new direction for the preparation of new two-dimensional composite materials and their application in gas sensors.