Multifunctional 0D–2D Ni2P Nanocrystals–Black Phosphorus Heterostructure

Fe-B alloy coupled with Fe clusters as an efficient cocatalyst for photocatalytic hydrogen evolution

Thin layers of black phosphorus present an ideal combination of a 2D material with a tunable direct bandgap and high carrier mobility. However the material suffers from degradation in ambient conditions due to an oxidation reaction which involves water, oxygen and light. We have measured the spatial profile of the conductivity on flakes of black phosphorus as a function of time using scanning microwave impedance microscopy. A microwave excitation (3 GHz) allows to image a conducting sample even when covered with a dielectric layer. We observe that on bare black phosphorus, the conductivity changes drastically over the whole surface within a day. We demonstrate that the degradation process is slowed down considerably by covering the material with a 10 nm layer of hafnium oxide. It is stable for more than a week, opening up a route towards stable black phosphorus devices in which the high dielectric constant of hafnium oxide can be exploited. Covering black phosphorus with a 15 nm boron nitride flake changes the degradation process qualitatively, it is dominated by the edges of the flake indicating a diffusive process and happens on the scale of days.

The development of transition metal-based catalysts for hydrogen evolution reaction with high active and stable performance is becoming an important means to reduce the energy consumption and cost of hydrogen products. In this paper, a two-step adding hydrothermal approach is conducted to manufacture 3D flower-like heteronanostructures composed of MoSe2-rGO-CNTs for the efficient electrocatalysis for hydrogen evolution reaction (HER) by acid medium hydrolysis. The physical structures and chemical compositions of the heteronanostructures were characterized with several techniques such as scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The heterostructures of the flower-like MoSe2-rGO-CNTs are formulated by in situ combination of the monolayer rGO-CNTs and MoSe2 crystals, where the excellent quality transverse heterostructures can boost the electrons transferring from the monolayer rGO-CNTs interfaces to the MoSe2 crystals, accomplishing the electronic deployment of MoSe2-rGO-CNTs heterostructures for prominent electrocatalytic performance. After optimization, the as-synthesized MoSe2-rGO-CNTs heterostructures catalyst exhibited an excellent electrocatalytic activity in 0.5 M H2SO4 solution with an overpotential of 206 mV at the current density of 10 mA·cm−2 and a Tafel slope of 46.74 mV·dec−1 for HER reaction. The optimal MoSe2-rGO-CNTs heteronanostructures display an excellent HER electrocatalytic activity and superior long-term durability in an acidic medium.

Black phosphorus (BP) is a newly discovered two-dimensional material that has promising applications from bioelectronics to biomedicine. However, facile oxidation of BP leads to changes in surface ...

Surface restructuring Prussian blue analog-derived bimetallic CoFe phosphides by N-doped graphene quantum dots for electroactive hydrogen evolving catalyst

Metal-organic frameworks derived bundled N-doped carbon nanowires confined cobalt phosphide nanocrystals as a robust electrocatalyst for hydrogen production

Controllable synthesized CoP-MP (M=Fe, Mn) as efficient and stable electrocatalyst for hydrogen evolution reaction at all pH values

Facile synthesis of MoS2/rGO-MOF hybrid material as highly efficient catalyst for hydrogen evolution

Black phosphorus (BP) nanosheets emerged as promising 2D nanomaterial that have been applied to eradicate antibiotic-resistant bacteria. However, their applications are limited by intrinsic ambient instability. Here, the ε-poly-l-lysine (ε-PL)-engineered BP nanosheets are constructed via simple electrostatic interaction to cater the demand for passivating BP with amplified antibacterial activity. The dual drug-delivery complex named BP@ε-PL can closely anchor onto the surface of bacteria, leading to membrane disintegration. Subsequently, in situ hyperthermia generated by BP under near-infrared (NIR) irradiation can precisely eradicate pathogenic bacteria. In vitro antibacterial studies verify the rapid disinfection ability of BP@ε-PL against Methicillin-resistant Staphylococcus aureus (MRSA) within 15min. Moreover, ε-PL can serve as an effective protector to avoid chemical degradation of bare BP. The in vivo antibacterial study shows that a 99.4% antibacterial rate in a MRSA skin infection model is achieved, which is accompanied by negligible toxicity. In conclusion, this work not merely provides a new conjecture for protecting the BP, but also opens a novel window for synergistic antibiotic-resistant bacteria therapy based on antimicrobial peptides and 2D photothermal nanomaterial.

Transition‐metal borides (TMBs) have recently attracted attention as excellent hydrogen evolution (HER) electrocatalysts in bulk crystalline materials. Herein, we show for the first time that VB and V3B4 have high electrocatalytic HER activity. Furthermore, we show that the HER activity (in 0.5 m H2SO4) increases with increasing boron chain condensation in vanadium borides: Using a −23 mV overpotential decrement derived from −0.296 mV (for VB at −10 mA cm−2 current density) and −0.273 mV (for V3B4) we accurately predict the overpotential of VB2 (−0.204 mV) as well as that of unstudied V2B3 (−0.250 mV) and hypothetical “V5B8” (−0.227 mV). We then derived an exponential equation that predicts the overpotentials of known and hypothetical VxBy phases containing at least a boron chain. These results provide a direct correlation between crystal structure and HER activity, thus paving the way for the design of even better electrocatalytic materials through structure–activity relationships.

Hydrogen is considered a clean and sustainable alternative energy source in future, and transition metal phosphides as substitutes for Pt-based electrocatalysts for the hydrogen evolution reaction (HER) have received widespread attention. However, exploring a facile way to synthesize efficient catalysts is still a challenge. In this work, we found a simple and safe way to obtain tungsten phosphide (WP) and the influence of synthesis temperature was also investigated. Moreover, with the modification of Ketjen Black, WP/KB heterostructures were gained, which showed an excellent HER performance in both acidic and alkaline solutions with Tafel slopes of 60 mV dec−1 and 66 mV dec−1, respectively. Furthermore, a possible improvement mechanism was also discussed.

Regulating the structural and interfacial properties of transition metal phosphides (TMPs) by coupling carbon-based materials with large surface areas to enhance hydrogen evolution reaction (HER) performance presents significant progress for water splitting technology. Herein, we constructed a composite substrate of a three-dimensional porous graphene oxide matrix (3D-GO) embedded in nickel foam (NF) to grow a Co2P electrocatalyst. Well-defined gladiolus-like Co2P nanowire arrays tightly anchored on the substrate show enhanced electrochemical characteristics for the hydrogen evolution reaction (HER) based on the promoting roles of 3D porous reduced GO (3D-rGO) derived from 3D-GO, which promotes the dispersion of active components, improves the rate of electron transfer, and facilitates the transport of water molecules. As a result, the obtained Co2P@3D-rGO/NF electrode exhibits superior HER activity in 1.0 M KOH media, achieving overpotentials of 36.5 and 264.7 mV at current densities of 10 and 100 mA cm-2, respectively. The electrode also has a low Tafel slope of 55.5 mV dec-1, a large electrochemical surface area, and small charge-transfer resistance, further revealing its mechanism of high intrinsic activity. Moreover, the electrode exhibits excellent HER stability and durability without surface morphology and chemical state changes.

The design of unprecious metal catalysts that exhibit both high-performance and durstability presents a significant challenge for hydrogen evolution reaction (HER). Non-precious metal-based 5NiWAg10-NiW@CF catalyst with efficient HER catalytic activity was developed and synthesized based on interfacial engineering modulation. The experimental results show that the heterogeneous interface not only promotes the exposure of the active site, but also accelerates the transfer of electrons. The 5NiWAg10-NiW@CF catalyst presents high HER electrocatalytic activity, achieving an overpotential of 118 mV at a current density of 0.01 A cm−2. Particularly, the favorable kinetics of 5NiWAg10-NiW@CF towards the HER in alkaline atmosphere was evidenced by its Tafel slope as low as 103 mV dec−1. This work offers a new perspective for the interfacial engineering optimization of catalysts.

Development of nonprecious metal-based electrocatalysts supporting hydrogen evolution reaction (HER) in the entire pH range has gained significant importance for harvesting green and renewable energy. Herein, we developed a novel electrocatalyst based on 3D carbon nanoarchitecture hybrid, which consists of CoP nanoparticles (CoP NPs) embedded into N-doped carbon nanotubes (NCNT), grafted on carbon polyhedron (CoP/NCNT-CP) that was prepared by carbonization and low-temperature phosphatization treatment of cobalt-based zeolite imidazole framework (ZIF). Benefiting from the strong synergistic effect and unique 3D structure, the CoP/NCNT-CP hybrid loaded on Ni foam exhibited excellent electrocatalytic HER performance in base with a low overpotential of 165 mV at a current density of 10 mA cm-2, which is competitive with the previously reported Co-based hybrid electrocatalysts. Furthermore, the CoP/NCNT-CP also demonstrated high HER electrocatalytic activities in both neutral and acidic conditions with the overpotentials of 203 and 305 mV at the current density of 10 mA cm-2. Additionally, the bifunctional CoP/NCNT-CP electrode simultaneously acted as an anode for hydrazine oxidation reaction (HzOR) and a cathode for HER. Excellent catalytic performance was demonstrated in base conditions with a low cell potential of 0.89 V at 10 mA cm-2, which was much lower than the voltage of overall water splitting (1.91 V) at the same current density.

Electrochemically assisted synthesis of three-dimensional FeP nanosheets to achieve high electrocatalytic activity for hydrogen evolution reaction