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• Phosphorene quantum dot modified prussian blue (PB) skeleton has been synthesized. • CN– groups passivate edges of phosphorene quantum dot (BP) to improve its stability. • CN– group can desire the band edge positions of BP to improve its catalytic activity. • PB skeleton can support BP to inhibit its agglomeration and transport the electron. • This nanostructure used as highly efficient electrocatalyst for hydrogen evolution. Facile liquid precipitation method assisted by liquid phase stripping has been used to prepare phosphorene quantum dot modified prussian blue porous skeleton structure. In this structure, the CN– group in prussian blue has larger chemical electronegativity than phosphorus atom, which can not only passivate the edges of phosphorene nanostructure, but also desire the valence band maximum and conduction band minimum band edge positions of black phosphorus for hydrogen generation in electrocatalytic water splitting. Moreover, the prussian blue porous network can be used as the support for phosphorene quantum dot and the medium for electron transport. This prussian blue supported phosphorene quantum dot porous network exhibits enhanced electrocatalytic hydrogen evolution performance with an over-potential of 148 mV at −10 mA cm−2 and a Tafel slope of 79 mV dec−1, which drastically surpass those of the black phosphorus. In addition, both the consecutive cyclic voltammetry and potentiostatic test reveal the outstanding electrocatalytic stability of the composite. This construction based on edge-modified phosphorene nanostructure presents efficient electrocatalys activity for water splitting. [ABSTRACT FROM AUTHOR]

[Display omitted] • (NiFeCo) 2 P@Au/CeO 2 generates strong HER and OER signals in neutral environment. • Dual-signal sensor was constructed using (NiFeCo) 2 P@Au/CeO 2 as electrocatalytic label. • HER and OER signals of this electrochemical immunosensor can be mutually verified. Sensitive and accurate detection of prostate-specific antigen (PSA) is great importance for the diagnosis and treatment of prostate cancer. However, constructing an electrochemical immunosensor with dual-signal detection can significantly improve the sensitivity and accuracy of PSA detection. Therefore, we prepared an electrolytic water bifunctional catalyst (NiFeCo) 2 P@Au/CeO 2 and used it as an electrocatalytic label to construct a dual-signal electrochemical immunosensor. Based on the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) signals of (NiFeCo) 2 P@Au/CeO 2 , the electrochemical immunosensor can achieve dual-signal detection of PSA. Research has shown that the dual-signal electrochemical immunosensor not only has a wide detection linear range (0.0001–100 ng mL−1), but also has extremely low detection limits (HER signal: 116.86 fg mL−1 and OER signal: 39.05 fg mL−1). In addition, it was used for PSA detection in human serum samples with good recovery. This dual-signal electrochemical immunosensor provides a new detection method for PSA and also develops a new dual-signal detection strategy for electrochemical immunosensor. [ABSTRACT FROM AUTHOR]

Electrochemical immunosensors are widely used in the detection of biomarkers. In order to further improve the detection sensitivity and accuracy, we constructed a dual-signal electrochemical immunosensor with CoTe 2 @CeO 2 nanocomposites (CoTe 2 @CeO 2 NCs) as an electrocatalytic label and successfully applied it to the detection of prostate-specific antigen (PSA). It was discovered that the CoTe 2 @CeO 2 NCs obtained by two-step hydrothermal process with outstanding oxygen evolution reaction (OER) activity and the Te- oxidation during OER, it produces a strong OER signal and a huge oxidation peak signal in neutral solution. Based on this, we propose an ingenious and simple dual-signal strategy that requires only one label, using CoTe 2 @CeO 2 NCs as an electrochemical immunosensor electrocatalytic label. Experimental results show that the developed dual-signal electrochemical immunosensor with a broad linear response (0.002 ∼ 200 ng mL−1) and very low detection limits (I peak : 8.26 fg mL−1, I OER : 448 fg mL−1) for PSA. It was successfully used for the detection of real samples with good detection and self-calibration capability. Furthermore, this constructed dual-signal immunosensor may also be used to detect other biomarkers by altering the recognition components. In conclusion, the construction strategy of this novel immunosensor is very meaningful for the early detection and treatment of diseases. [Display omitted] ● CoTe 2 @CeO 2 NCs generates both peak and OER signals in neutral environment. ● A dual-signal immunosensor was constructed using CoTe 2 @CeO 2 NCs as the label. ● This electrochemical immunosensor with excellent detection performance for PSA. ● Dual signal inter-validation and self-calibration for more reliable assay results. [ABSTRACT FROM AUTHOR]

• Highly dispersed pseudoamorphous metal phosphide ((NiFeCo) 2 P-PA) have prepared. • The formation of pseudoamorphous catalyst was promoted by hydrothermal process. • Pseudoamorphous structure has more active sites and higher intrinsic activity. • (NiFeCo) 2 P-PA has excellent water electrolysis stability under industrial current. • DFT calculation shows that the pseudoamorphous catalyst has lower OER energy barrier. Industrial hydrogen production based on water electrolysis requires the catalysts that operate stably at ultra-high current densities for extended periods. Herein, we prepared a highly dispersed pseudoamorphous metal phosphide cluster catalyst supported by nitrogen-doped carbon layer ((NiFeCo) 2 P-PA/NF). Due to its excellent intrinsic activity and stable structure, (NiFeCo) 2 P-PA/NF can drive oxygen evolution unremittingly for more than 160 h at a current density of 500 mA cm−2 (365 mV). Theoretical calculations also show that the energy barrier of the rate-determining step in the (NiFeCo) 2 P-PA is effectively is reduced. This alkaline hydrogen production system using (NiFeCo) 2 P-PA/NF as cathode and anode can meet commercial standards, showing low cell voltage (1.590 V) and extraordinary stability (over 300 h) at industrial current densities, and driving a cell voltage of only 1.372 V for 100 mA cm−2 in the urea alkaline hydrogen production system, demonstrating its potential for industrial applications. [ABSTRACT FROM AUTHOR]

Based on the OER signal of Au@CoFe-(oxy)hydroxide, a novel electrochemical immunosensor was constructed for detection of carcinoembryonic antigen (CEA). The proposed electrochemical immunosensor exhibited a good linear response from 0.0001 to 200 ng mL−1 and a low detection limit of 0.0534 pg mL−1. [Display omitted] • Immunosensor based on electrocatalytic signal has been constructed for CEA detection with a satisfied linear range and detection limit. • Au@CeO 2 combined with Ab 1 through the formation of Au-S bonds and ester-like bonds. • Au@CoFe-(oxy)hydroxide with a large specific surface area and an excellent OER signal. Carcinoembryonic antigen (CEA) is a group of glycoproteins highly associated with cell adhesion and is an important antigen as a tumor biomarker commonly used in clinical diagnosis. Therefore, CEA detection plays a significant role in early clinical tumor diagnosis. In this study, an electrocatalytic signal labeled immunosensor was constructed for CEA ultrasensitive detection. We use a core–shell Au@CeO 2 modified glassy carbon electrode (GCE) to capture more primary antibody (Ab 1). The core–shell structure captures Ab 1 through Au-S and O C–O bonds, providing more binding sites and a more stable binding force for Ab 1. Because of the large specific surface area of the Au@CoFe-(oxy)hydroxide nanosheets and its outstanding oxygen evolution reaction (OER) signal under neutral medium, Au@CoFe-(oxy)hydroxide combined with secondary antibody (Ab 2) as the signal tag and signal amplifier of the sensor. The proposed electrochemical immunosensor exhibited a good linear response from 0.0001 ng mL−1 to 200 ng mL−1 and a low detection limit of 0.0534 pg mL−1. The effectiveness of the sensor is verified by the standard addition method. This work provides a novel research approach for the clinical detection of tumor markers. [ABSTRACT FROM AUTHOR]

[Display omitted] • CoFe-(oxy)hydroxide nanosheets are prepared by transforming CoFe PBA NBs precursor. • CoFe-(oxy)hydroxide shows excellent OER activity in neutral medium. • The CoFe-(oxygen) hydroxide as an electrocatalytic label for signal amplification. • The biosensor has a wide linear range and low detection limit for PCT detection. • It obtained a high recovery in human serum sample analysis. Nanomaterials play an important role in the fields of electrocatalysis and electrochemical immunosensor. As we all know, electrocatalytic oxygen evolution reaction (OER) can generate intensive current response under alkaline and even neutral conditions, and no by-products are produced. In recent years, OER based on non-noble metal nanocatalysts has become a research focus in the field of new energy, but there are few reports on using it as an electrocatalytic immunosensor label for biomolecule detection. In this study, we successfully synthesized CoFe-(oxy)hydroxide nanosheets through transforming CoFe prussian blue analogue (CoFe PBA). Based on the excellent OER activity of CoFe-(oxy)hydroxide in neutral solution, it was used as a new electrocatalytic marker for capturing procalcitonin (PCT) secondary antibody (Ab 2). Meanwhile, gold nanoparticles (Au NPs) modified glassy carbon electrode (GCE) was utilized as immunosensor platform to immobilize PCT primary antibodies (Ab 1). The linear range of the immunosensor for PCT detection is 0.0005 ∼ 100 ng mL−1, and the detection limit is 0.33 pg mL−1. Furthermore, a high recovery was obtained when this proposed method was applied to analysis human serum samples. This work not only provides a new method for clinical analysis of PCT, but also extends the application of electrocatalytic OER. [ABSTRACT FROM AUTHOR]

• A porous Mo-doped CoFe LDH/NF catalysts was prepared by electrochemical transformation Mo-doped CoFe PBA/NF. • Mo doping modulated the electronic structure of CoFe LDH/NF. • Catalysts only require 331 mV and 227 mV drive 100 mA cm−2 for OER and HER in alkaline medium. • The electrode pair shows high activity and durability in alkaline media at large current density. [Display omitted] Facile preparation of efficient, low-cost, and stable bifunctional electrocatalysts for overall water splitting remains a big challenge. Herein, we successfully synthesized Mo-doped CoFe layered double hydroxides (Mo-doped CoFe LDH/NF) nanosheets by electrochemical transformation of Mo-doped CoFe prussian blue nanocubes on nickel foam (Mo-doped CoFe PBA/NF) for highly efficient overall water splitting. The catalyst exhibits outstanding oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance after electrochemical transformation, which is due to the abundant edge defects of Mo-doped CoFe LDH/NF can expose more active sites. Meanwhile, Mo6+ has a strong electron absorption ability, which could adjust the electronic structure and stabilize the high valence active sites. It only requires a low overpotential for OER (331 mV) and HER (227 mV) to reach 100 mA cm−2 in alkaline media, respectively. Notably, when it was employed as a bifunctional electrode, Mo-doped CoFe LDH/NF displays a low potential of 1.55 V to reach 100 mA cm−2 coupled with long-term water splitting stability in an alkaline electrolyte. This work not only developed a novel method for the synthesis of efficient double-layer hydroxide catalysts, but also paved the way for the rational design of bifunctional electrocatalysts with practical application value. [ABSTRACT FROM AUTHOR]

Designing an efficient and stable electrocatalyst is key for the enhanced oxygen evolution reaction. This paper proposes a hydrothermal method for synthesising Sn-doped CoO x (OH) 2(1-x) (CoO x (OH) 2(1-x) -Sn(Ⅳ)). During the preparation process, the morphology of the precursor was controlled by an anionic surfactant. The precursor of the layered structure was mainly formed through the bonding of anionic group SO 3 H− in SDBS with metal cation Co2+, and the surface area and reaction sites of the precursor were clearly increased. Finally, CoO x (OH) 2(1-x) -Sn(Ⅳ) urchin-like spheres were hydrothermally synthesised. The current density of the CoO x (OH) 2(1-x) -Sn(Ⅳ) obtained at a potential of 1.95 V was 124.8 mA cm−2, i.e. 2.8 times higher than that of the precursor (44.9 mA cm−2). The Tafel slope of the precursor was 156.1 mV dec−1, i.e. 3.3 times that of CoO x (OH) 2(1-x) -Sn(Ⅳ) (48.0 mV dec−1). [ABSTRACT FROM AUTHOR]