Cui Ye

Highly sensitive electrochemiluminescenc assay of acetylcholinesterase activity based on dual biomarkers using Pd–Au nanowires as immobilization platform

One-dimensional Pd-Au nanowires (Pd-Au NWs) were prepared and applied to fabricate an electrochemiluminescence (ECL) biosensor for the detection of acetylcholinesterase (AChE) activity. Compared with single-component of Pd or Au, the bimetallic nanocomposite of Pd-Au NWs offers a larger surface area for the immobilization of enzyme, and displays superior electrocatalytic activity and efficient electron transport capacity. In the presence of AChE and choline oxidase (ChOx), acetylcholine (ATCl) is hydrolyzed by AChE to generate thiocholine, then thiocholine is catalyzed by ChOx to produce H2O2 in situ, which serves as the coreactant to effectively enhance the ECL intensity in luminol-ECL system. The detection principle is based on the inhibited AChE and reactivated AChE as dual biomarkers, in which AChE was inhibited by organophosphorus (OP) agents, and then reactivated by obidoxime. Such dual biomarkers method can achieve credible evaluation for AChE activity via providing AChE activity before and after reactivation. The liner range for AChE activity detection was from 0.025 U L(-1) to 25 KU L(-1) with a low detection limit down to 0.0083 U L(-1).

Nanosized Metal Phosphides Embedded in Nitrogen‐Doped Porous Carbon Nanofibers for Enhanced Hydrogen Evolution at All pH Values

Transition-metal phosphides (TMPs) have emerged as promising catalyst candidates for the hydrogen evolution reaction (HER). Although numerous methods have been investigated to obtain TMPs, most rely on traditional synthetic methods that produce materials that are inherently deficient with respect to electrical conductivity. An electrospinning-based reduction approach is presented, which generates nickel phosphide nanoparticles in N-doped porous carbon nanofibers (Ni2 P@NPCNFs) inu2005situ. Ni2 P nanoparticles are protected from irreversible fusion and aggregation in subsequent high-temperature pyrolysis. The resistivity of Ni2 P@NPCNFs (5.34u2005Ωu2009cm) is greatly decreased by 104 times compared to Ni2 P (>104 u2005Ωu2009cm) because N-doped carbon NFs are incorporated. As an electrocatalyst for HER, Ni2 P@NPCNFs reveal remarkable performance compared to other previously reported catalysts in acidic media. Additionally, it offers excellent catalytic ability and durability in both neutral and basic media. Encouraged by the excellent electrocatalytic performance of Ni2 P@NPCNFs, a series of pea-like Mx P@NPCNFs, including Fe2 P@NPCNFs, Co2 P@NPCNFs, and Cu3 P@NPCNFs, were synthesized by the same method. Detailed characterization suggests that the newly developed method could render combinations of ultrafine metal phosphides with porous carbon accessible; thereby, extending opportunities in electrocatalytic applications.

Bimetal–organic-frameworks-derived yolk–shell-structured porous Co2P/ZnO@PC/CNTs hybrids for highly sensitive non-enzymatic detection of superoxide anion released from living cells

We report a general approach for the synthesis of yolk-shell-structured porous dicobalt phosphide/zinc oxide@porous carbon polyhedral/carbon nanotube hybrids (Co2P/ZnO@PC/CNTs) derived from bimetal-organic frameworks, and explore their potential utilization in the electrochemical sensing of superoxide anions. Beyond our expectation, the trace level of O2˙- released from living cells has also been successfully captured by our designed sensor. The presented strategy for the controlled design and synthesis of bimetal-organic frameworks-derived functional nanomaterials offers prospects of developing highly active electrocatalysts in non-enzyme sensors.

Platanus hispanica-inspired design of Co–carbon nanotube frameworks through chemical vapor deposition: a highly integrated hierarchical electrocatalyst for oxygen reduction reactions

In this communication, a novel platanus hispanica-like, highly integrated hierarchical electrocatalyst, with Co-carbon nanotubes anchored through porous Co embedded carbon sphere frameworks (Co-CNTFs), was fabricated using a chemical vapor deposition (CVD) method. More importantly, the prepared Co-CNTFs demonstrate even better activity than commercial Pt electrocatalysts in an alkaline medium. This presented CVD approach provides an effective way to grow metal-CNTs in situ through various metal-complex-derived functional nanomaterials and can be expanded to metallic oxide, metallic sulfide, and metallic phosphide, among others, to introduce carbon nanotube frameworks with a multitude of potential applications.

Nanostructured cobalt phosphates as excellent biomimetic enzymes to sensitively detect superoxide anions released from living cells.

Monitoring superoxide anion radicals in living cells has been attracting much academic and industrial interest due to the dual roles of the radicals. Herein, we synthesized a novel nanostructured cobalt phosphate nanorods (Co3(PO4)2 NRs) with tunable pore structure using a simple and effective micro-emulsion method and explored their potential utilization in the electrochemical sensing of superoxide anions. As an analytical and sensing platform, the nanoscale biomimetic enzymes Co3(PO4)2 NRs exhibited excellent selectivity and sensitivity towards superoxide anion (O2•-) with a low detection limit (2.25nM), wide linear range (5.76-5396nM), and long-term stability. Further, the nanoscale biomimetic enzyme could be efficiently applied in situ to electrochemically detect O2•- released from human malignant melanoma cells and normal keratinocyte, showing excellent real time quantitative detection capability. This material open up exciting opportunities for implementing biomimetic enzymes in nanoscale transition metal phosphates and designing enzyme-free biosensors with much higher sensitivity and durability in health and disease analysis than those of natural one.

Controlled synthesis of Mn3(PO4)2 hollow spheres as biomimetic enzymes for selective detection of superoxide anions released by living cells

AbstractThe authors have synthesized nanostructured manganese(II) phosphate hollow spheres [Mn3(PO4)2 HS] with tunable pore structure by using a micro-emulsion method. These, if deposited on a glassy carbon electrode (GCE), are shown to be a viable material for electrochemical sensing of superoxide (radical) anion (O2˙−) at a typical working voltage of 0.7xa0V (vs. SCE). Hence, they act as biomimetic enzymes that allow for the determination of O2˙− with a very low detection limit (1.35xa0nM), wide linear range (5xa0nM to 0.4xa0mM), and good long-term stability. The modified GCE was applied in-situ to the electrochemical determination of O2− that is released from human malignant melanoma cells and normal keratinocyte, and it showed excellent real time analytical capability. In our perception, the use of this material offers exciting opportunities in terms of implementing nanoscale transition metal phosphates as biomimetic enzymes in enzyme-free diagnostic sensors. Conceivably, these will offer higher sensitivity and longer durability than assays based on the use of natural enzymes.n Graphical abstractMicro-emulsion method-derived nanostructured manganese(II) phosphate hollow spheres [Mn3(PO4)2 HS] as biomimetic enzymes to sensitively detect superoxide anions released by living cells.

Ternary NixCo3-xS4 with Fine Hollow Nanostructure as Robust Electrocatalyst for Hydrogen Evolution

The elaborate design of efficient and stable electrocatalysts from earth‐abundant elements to replace precious Pt for the hydrogen evolution reaction (HER) is an ongoing challenge. Doping metallic compounds with additional metal atoms provides the opportunity to tune their electronic and crystal structures, which thus ameliorates their electrocatalytic properties. Herein, we report for the first time a robust and earth‐abundant Ni‐doped Co3S4 catalyst grown on carbon cloth that shows high HER activity in 1u2009m KOH. Morphology evolution and HER activity were found to be strongly related to the Ni substitution ratio. Electrochemical tests showed a low overpotential of 72.82u2005mV at 10u2005mAu2009cm−2, a small Tafel slope of 49.44u2005mVu2009dec−1, and long‐term durability over 46u2005h HER operation for the Ni0.5Co2.5S4 nanotube array self‐standing on carbon cloth. These data indicate that atomic modulation of Ni plays an important role in optimizing the morphology and electrocatalytic activity by greatly expanding the active sites in the electrocatalyst. Further, the 3u2009D self‐standing nanotube array highly aids in the exposure of active species and the transfer of electrons and charges, which substantially boosts the reaction kinetics and stability of the structure.

MoP nanoparticles with a P-rich outermost atomic layer embedded in N-doped porous carbon nanofibers: Self-supported electrodes for efficient hydrogen generation

Despite being pursued for a long time, hydrogen production via water splitting is still a huge challenge mainly due to a lack of durable and efficient catalysts. Molybdenum phosphide (MoP) is theoretically capable of efficient hydrogen evolution reaction (HER) catalysis, however, there is still room for further improvement in its performance. Herein, we propose a design for MoP with a P-rich outermost atomic layer for enhancing HER via complementary theoretical and experimental validation. The correlation of computational results suggests that the P-terminated surface of MoP plays a crucial role in determining its high-efficiency catalytic properties. We fabricated a P-rich outermost atomic layer of MoP nanoparticles by using N-doped porous carbon (MoP@NPCNFs) to capture more P on the surface of MoP and limit the growth of nanoparticles. Further, the as-prepared material can be directly employed as a self-supported electrocatalyst, and it exhibits remarkable electrocatalytic activity for HER in acidic media; it also reveals excellent long-term durability for up to 5,000 cycles with negligible loss of catalytic activity.

Engineering the nanostructure of molybdenum nitride nanodot embedded N-doped porous hollow carbon nanochains for rapid all pH hydrogen evolution

Engineering the microstructure at the atomic scale is paramount to developing effective catalysts due to the active sites and mass/charge transfer ability of catalysts severely limited by their microstructure. Herein, we nanoengineer unique necklace-like nanochains composed of molybdenum nitride embedded N-doped carbon, in which the series-wound nanochains are built from hollow beads with a very thin porous wall. MoN nanodots were downsized to 3 nm and uniformly embedded in hollow N-doped porous carbon pearls and wires. The unique hierarchical hollow cavity and ultrathin wall structure of the nanochains offer a high effective reaction chamber, more active sites, and mass/charge transfer for remarkably fast HER. The resultant MoN@NPCNCs exhibit an extremely low HER overpotential of 72 mV at 10 mA cm−2, a low Tafel slope of 53.21 mV dec−1 in an acidic solution, which is far lower than those of MoN embedded N-doped carbon nanofibers (MoN@NPCNFs, 139.21 mV vs. RHE/82.69 mV dec−1), and other previously reported MoN based catalysts. Density functional theory (DFT) calculations reveal that MoN and N-doped carbon synergistically optimizes the free energy of hydrogen adsorption on the active sites. Furthermore, this catalyst also offers an excellent electrocatalytic ability and durability in both neutral and alkaline media.

Self-Interconnected Porous Networks of NiCo Disulfide as Efficient Bifunctional Electrocatalysts for Overall Water Splitting

Electrochemical splitting of water has been viewed as a highly efficient technique to produce clean hydrogen and oxygen energy. However, designing inexpensive multifunctional electrocatalysts with high performance is a great challenge. Here, a unique three-dimensional catalyst of self-interconnected porous Ni-Co disulfide networks grown on carbon cloth [(Ni0.33Co0.67)S2 nanowires (NWs)/CC] was prepared by a facile hydrothermal method coupled with further low-temperature sulfuration strategy. As a bifunctional electrocatalyst, (Ni0.33Co0.67)S2 NWs/CC exhibits a remarkable activity to catalyze both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). To drive a current density of 100 mA cm-2, (Ni0.33Co0.67)S2 NWs/CC needs the overpotentials of 156 mV in 0.5 M H2SO4 solution and 334 mV in 1.0 M KOH solution for HER, respectively. Moreover, when used as a catalyst of OER, (Ni0.33Co0.67)S2 NWs/CC needs an overpotential of 295 mV to produce a current density of 100 mA cm-2. The excellent electrochemical properties are mainly attributed to the synergetic catalysis of a Ni-Co-based bimetallic disulfide, the porous network structure, and the high conduction of CC. Moreover, the two-electrode alkaline water-splitting system constructed by (Ni0.33Co0.67)S2 NWs/CC only needs a low cell voltage of 1.57 V to approach 10 mA cm-2. This work offers more new insights for the design and preparation of the non-noble metal catalysts based on transition metal sulfides with excellent electrocatalytic performance in overall water splitting.