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Cell-specific aptamers offer a powerful tool to study membrane receptors at the single-molecule level. Most target receptors of aptamers are highly expressed on the cell surface, but difficult to analyze in situ because of dense distribution and fast velocity. Therefore, we herein propose a random sampling-based analysis strategy termed ligand dilution analysis (LDA) for easily implemented aptamer-based receptor study. Receptor density on the cell surface can be calculated based on a regression model. By using a synergistic ligand dilution design, colocalization and differentiation of aptamer and monoclonal antibody (mAb) binding on a single receptor can be realized. Once this is accomplished, precise binding site and detailed aptamer-receptor binding mode can be further determined using molecular docking and molecular dynamics simulation. The ligand dilution strategy also sets the stage for an aptamer-based dynamics analysis of two- and three-dimensional motion and fluctuation of highly expressed receptors on the live cell membrane.

Searching for a simple and fast strategy to effectively enhance the oxygen evolution reaction (OER) performance of non-noble-metal electrocatalysts in alkaline media remains a significant challenge. Herein, the OER activity of NiFe-LDH nanoarray on carbon cloth (NiFe-LDH/CC) in alkaline media is shown to be greatly boosted by an amorphous NiFe-Borate (NiFe-Bi ) layer formation on NiFe-layered double hydroxide (NiFe-LDH) surface. Such a NiFe-LDH@NiFe-Bi /CC catalyst electrode only needs an overpotential of 294 mV to drive 50 mA cm-2 in 1.0 m KOH; 116 mV less than that needed by NiFe-LDH/CC. Notably, this electrode also demonstrates strong long-term electrochemical durability. The superior activity is ascribed to the pre-formed amorphous NiFe-Bi layer effectively promoting active species generation on the NiFe-LDH surface. This work opens up exciting new avenues for developing high-performance water-oxidation catalyst materials for application.

The design and development of earth-abundant electrocatalysts for efficient full water splitting under mild conditions are highly desired but still remain a challenging task. In this study, we describe the development of homologous Fe-doped Co-based nanoarray as complementary catalysts for high-performance and durable water splitting in near-neutral media. Fe-doped Co-phosphate-borate nanoarray on carbon cloth (Fe-Co-Pi-Bi/CC) derived from Fe-doped CoP nanoarray on CC (Fe-CoP/CC) via oxidative polarization behaves as a highly active bimetallic electrocatalyst for water oxidation with the demand of overpotential of 382 mV to afford a geometrical catalytic current density of 10 mA cm-2 in 0.1 M potassium borate (K-Bi, pH: 9.2). Fe-CoP/CC is also superior in activity for hydrogen evolution reaction, capable of driving 10 mA cm-2 at overpotential of only 175 mV in 0.1 M K-Bi. The two-electrode water electrolyser using Fe-Co-Pi-Bi/CC as anode and Fe-CoP/CC as cathode achieves 10 mA cm-2 water splitting current at a cell voltage of 1.95 V with strong long-term electrochemical durability.

The development of high-performance and cost-effective water oxidation catalysts operating under mild conditions is attractive for the conversion of electricity into chemical fuels. In this communication, we report the in situ electrochemical development of a Ni-Bi layer (5–8 nm thick) on a NiS2 nanoarray supported on carbon cloth (i.e., NiS2@Ni-Bi/CC) for efficient water oxidation in 0.1 m potassium borate electrolyte at pH 9.2. As a durable 3 D catalyst electrode, core–shell-structured NiS2@Ni-Bi/CC shows excellent catalytic activity for water oxidation and approaches a geometrical catalytic current density of 20 mA cm−2 at an overpotential of 486 mV, with long-term electrochemical stability for at least 24 h with a high turnover frequency of 0.28 mol O2 s−1 at an overpotential of 500 mV and nearly 100 % Faradic efficiency for oxygen evolution.

Developing low cost and efficient anode and cathode materials toward electrocatalysis are regarded as one of the most desirable yet challenging research directions, which are intimately related to the pressing energy, environmental and human health issues. Currently, 3 D foam (such as Ni foam, Cu foam, and graphene foam) based heterogeneous catalysts have been intensively explored for actively catalyzing the electrode reactions. Their inherent characteristics of stereo-network structure, high specific area and large pore volume not only provide better mass transport of reactants to electrode surfaces, but also pave 3 D electron transport pathways. Herein, recent significant progress and rational design of foam-based electrocatalysts are reviewed. In addition, some insights into current challenges and future directions of foams for efficient electrocatalysis are proposed and discussed.

Nickel-borate nanosheets array on titanium mesh (Ni-Bi NA/TM) was derived from NiSe2 nanosheets array on titanium mesh (NiSe2 NA/TM) by electrochemical transformation. As a three-dimensional electrode, Ni-Bi NA/TM exhibited high catalytic activity toward the oxygen evolution reaction and required a low overpotential of 430 mV at 10 mAcm(-2) in 0.1 M potassium borate (pH 9.2), with outstanding long-term stability and high turnover frequency.

It is highly needed but still a difficult challenge to achieve energy-saving electrolytic hydrogen generation. In this communication, we describe the first use of iron phosphide nanosheets array on Ni foam as a high-active and durable catalyst for electrochemical hydrazine oxidation reaction (HzOR) in alkaline media. The high hydrogen-evolving activity of this catalyst electrode and the substitution of sluggish oxygen evolution with thermodynamically more favorable HzOR enables the construction of a stable two-electrode energy-efficient electrolytic hydrogen generation system capable of driving 125 mA cm−2 at a cell voltage of 0.5 V to in 1.0 M KOH with 0.5 M hydrazine.

Among reported electrode materials, a nanoarray is an attractive architecture for molecular detection because of its large specific surface area and easy accessibility for target molecules. Here, a new Fe3 N-Co2 N nanowires array grown on carbon cloth (Fe3 N-Co2 N/CC) is reported as a non-noble-metal bifunctional catalyst electrode for high-performance glucose oxidation and H2 O2 reduction. As an electrochemical non-enzymatic sensor for glucose detection, Fe3 N-Co2 N/CC shows a fast response time of 8 s, a low detection limit (LOD) of 77 nm (signal/noise=3), and a high sensitivity of 4333.7 μA mm-1 cm-2 . As an H2 O2 sensor, it shows a LOD of 59 nm (signal/noise=3) and a sensitivity of 2273.8 μA mm-1 cm-2 with a response time of 2 s. In addition, the proposed sensor is stable with high selectivity, specificity, and reproducibility, and its application for real sample analysis has been successfully demonstrated.

Inorganic halide perovskite quantum dots (IHPQDs) have recently emerged as a new class of optoelectronic nanomaterials that can outperform the existing hybrid organometallic halide perovskite (OHP), II-VI and III-V groups semiconductor nanocrystals, mainly due to their relatively high stability, excellent photophysical properties, and promising applications in wide-ranging and diverse fields. In particular, IHPQDs have attracted much recent attention in the field of photoelectrochemistry, with the potential to harness their superb optical and charge transport properties as well as spectacular characteristics of quantum confinement effect for opening up new opportunities in next-generation photoelectrochemical (PEC) systems. Over the past few years, numerous efforts have been made to design and prepare IHPQD-based materials for a wide range of applications in photoelectrochemistry, ranging from photocatalytic degradation, photocatalytic CO2 reduction and PEC sensing, to photovoltaic devices. In this review, the recent advances in the development of IHPQD-based materials are summarized from the standpoint of photoelectrochemistry. The prospects and further developments of IHPQDs in this exciting field are also discussed.

Poly(toluidine blue) nanowires (PTBNWs) with an average diameter of ca. 200 nm and length of ca. 5 μm were synthesized for the first time using a template-directed electropolymerization strategy with a nanopore polycarbonate (PC) membrane template. Their morphological characterization was carried out by scanning electron microscopy (SEM) and transmission electron microscope (TEM). By electrochemical polymerization, horseradish peroxidase (HRP) was encapsulated in situ in PTBNWs (denoted as PTBNWs-HRP) for potential biosensor applications. PTBNWs-HRP was then modified on a glassy carbon (GC) electrode. In the system obtained, the PTBNWs served as an excellent redox mediator and exhibited high efficiency of electron transfer between the HRP and the GC electrode for the reduction of H2O2. The proposed electrode can be used as an excellent amperometric sensor for H2O2 at −0.1 V with a linear response range covering from 1 μM to 28 mM, a detection limit of 1 μM (based on S/N=3) and a fast response time of less than 8 s.

There is an urgent demand to develop earth-abundant electrocatalysts for efficient and durable water oxidation under mild conditions. A nickel-substituted cobalt-borate nanowire array is developed on carbon cloth (Ni-Co-Bi/CC) via oxidative polarization of NiCo2 S4 nanoarray in potassium borate (K-Bi). As a bimetallic electrocatalyst for water oxidation, such Ni-Co-Bi/CC is superior in catalytic activity and durability in 0.1 m K-Bi (pH: 9.2), with a turnover frequency of 0.33 mol O2 s-1 at the overpotential of 500 mV and nearly 100% Faradaic efficiency. To drive a geometrical catalytic current density of 10 mA cm-2 , it only needs overpotential of 388 mV, 34 mV less than that for Co-Bi/CC, outperforming reported non-noble-metal catalysts operating under benign conditions. Notably, its activity is maintained over 80 000 s. Density functional theory calculations suggest that the O* to OOH* conversion is the rate-determining step and Ni substitution decreases the free energy on Co-Bi from 2.092 to 1.986 eV.

As a non-toxic species, Zn fulfills a multitude of biological roles, but its promoting effect on electrocatalysis has been rarely explored. Herein, the theoretic predications and experimental investigations that nonelectroactive Zn behaves as an effective promoter for CoP-catalyzed hydrogen evolution reaction (HER) in both acidic and alkaline media is reported. Density function theory calculations reveal that Zn doing leads to more thermal-neutral hydrogen adsorption free energy and thus enhanced HER activity for CoP catalyst. Electrochemical tests show that a Zn0.08Co0.92P nanowall array on titanium mesh (Zn0.08Co0.92P/TM) needs overpotentials of only 39 and 67 mV to drive a geometrical catalytic current of 10 mA cm-2 in 0.5 m H2SO4 and 1.0 m KOH, respectively. This Zn0.08Co0.92P/TM is also superior in activity over CoP/TM for urea oxidation reaction (UOR), driving 115 mA cm-2 at 0.6 V in 1.0 m KOH with 0.5 m urea. The high HER and UOR activity of this bifunctional electrode enables a Zn0.08Co0.92P/TM-based two-electrode electrolyzer for energy-saving hydrogen production, offering 10 mA cm-2 at a low voltage of 1.38 V with strong long-term electrochemical stability.