•A porous NiCo diselenide nanosheets were uniformly arrayed on carbon cloth.•The 3D architecture facilitates charge transfer with huge surface area.•These composites show a superior performance in water splitting.•H2 evolution overpotential is 108 mV with a Tafel slope small as 31.6 mV·dec−1.•O2 evolution overpotential is 258 mV with a Tafel slope small as 42.3 mV·dec−1.we report the synthesis of porous NiCo diselenide nanosheets arrayed on carbon cloth (CC) via ion exchange with a hydroxide precursor. This bind-free three-dimensional (3D) architecture possesses the huge specific surface area and facilitates ion transport and charge transfer, leading to a superior performance in water splitting as a bifunctional catalyst for both H2 and O2 evolution reaction (HER and OER). The as-prepared NiCo diselenide/CC composites show a high HER capability in 0.5 M H2SO4 solution with a Tafel slope as small as 31.6 mV·dec−1. They offer a HER current of 10 mA·cm−2 at a low overpotential of 108 mV. Their OER efficiency is also remarkable in 1 M KOH solution with a small Tafel slope of 42.3 mV·dec−1 and a low overpotential of 258 mV at 10 mA·cm−2. This 3D porous NiCo diselenide nanosheet array holds a promise as an attractive alternative to precious catalysts of water splitting with high activity and long-term stability.

•Ultrathin NiCo layered double hydroxide nanosheets were arrayed on carbon cloth.•Their three-dimensional structure favors mass transport and electron transfer.•They show a remarkable activity for glucose oxidation.•They can be used as a bind-free biosensor in nonenzymatic glucose detection.•This amperometric sensing exhibits a high sensitivity and selectivity.An ultrathin NiCo layered double hydroxide (LDH) nanosheet array was constructed on carbon cloth (CC) by one-pot co-precipitation approach. The NiCo LDH nanosheets possess high surface specific area and their interconnected three-dimensional (3D) structure allows easy access for electrolyte ions to process rapid and reversible faradic reactions. The as-prepared NiCo LDH/CC composites show a remarkable activity for glucose oxidation, which can be used as a binder-free biosensor for glucose detection. Under optimized conditions, the sensitivity can reach up to 5.12 μA μM−1 cm−2, the liner range covers four orders of magnitude from 1 μM to 1.5 mM, and the detection limit can be low as 0.12 μM. Besides, this biosensor also shows superior selectivity, good stability, and easy reproducibility, holding promise as a good candidate for enzymeless glucose sensing.

•Copper hexacyanoferrate was uniformly covered on carbon nanotubes.•Cs+ ion can be exchanged using this hybrid by controlling the electrode potential.•The maximum of Cs+ adsorption capacity is 310 mg·g−1 in 50 μM Cs+ solution.•The distribution coefficient of Cs+ in this hybrid reaches up to 568 L·g−1,.•This hybrid can be regenerated with high stability for Cs+ exchange.A novel electrochemical separation system was developed based on copper hexacyanoferrate/multiwalled carbon nanotube (CuHCF/MWCNT) hybrids for selectively removing cesium from wastewater. These CuHCF/MWCNT hybrids were prepared by co-precipitation strategy. The as-prepared CuHCF nanoparticles were uniformly covered on MWCNTs to form a dendritic core-shell structure. This novel structure can improve CuHCFs conductivity, making CuHCFs more accessible for ion exchange. The uptake and release of alkali ion in CuHCF/MWCNT hybrids can be shifted mutually by switching the applied potentials between the anode and cathode. This ion exchange is a fast and reversible process associated with electron transfer in CuHCFs. The potential response depends on the radius of alkali ion. Using this electrochemical adsorption system (EAS), the maximum adsorption capacity (Qmax) of Cs+ ion for CuHCFs/MWCNT hybrids reaches up to 310 mg·g−1 in 50 μM Cs+ solution with a distribution coefficient Kd of 568 L·g−1, superior to the Cs+ removal performance by the conventional adsorption system (Qmax 230 mg·g−1, Kd 389 L·g−1). Besides, CuHCF/MWCNT hybrids can be regenerated electrochemically. In addition to the advantages in Cs+ removal performance and electrochemical regenerability, they can maintain considerable stability with uptake capacity retention of 85% after 100 cycles of adsorption and regeneration.

Ultrathin molybdenum sulfide (MoSx) nanosheets were uniformly grown on multiwalled carbon nanotubes (MWCNTs) via a solvothermal process. These MoSx nanosheets possess high density of active sites, full of the basal MoSx edges and unsaturated S atoms, and their one-dimensional (1D) core-shell architecture facilitates electron transfer and charge transport, leading to a superior performance in H2 evolution reaction (HER). These caterpillar-like MoSx@MWCNT hybrids show a high HER capability in 0.5 M H2SO4 solution with a low overpotential of 102 mV vs standard hydrogen electrode (SHE) and a small Tafel slope of 35 mV dec−1 at 10 mA cm−2. Their HER activity presents no significant decay during potential polarization at 150 mV vs SHE for over 5 h.

•Pt nanoparticles were uniformly deposited on graphene with MoO3. Their size can be tuned by controlling MoO3 loading. These Pt catalysts are high active on methanol oxidation. They also show high tolerance to CO poisoning.Pt nanoparticles (NPs) were uniformly deposited on the reduced graphene oxides (RGOs) by one-pot thermoreduction strategy with assist of MoO3. MoO3 can significantly reduce the size of Pt NPs on RGOs. These Pt NPs can be averaged to be 3.0 to 4.1 nm with MoO3 loading from 27.4 to 8.8%. Without MoO3, the size of Pt NPs can reach up to 15.2 nm. In addition, MoO3 in Pt-MoO3/RGO catalysts conducts a surface-confined reversible electron transfer. And the Pt-MoO3/RGO catalysts show strong resistance to CO poisoning and high activity towards methanol oxidation reaction (MOR). Among these Pt-based catalysts, Pt-MoO3/RGO catalysts with 16.5% MoO3 loading possess a largest MOR current up to 610 mA mg−1 Pt with a smallest deteriorate rate of 0.000425 s−1 polarizing for 5000 s at 0.65 V. These results demonstrate commercial feasibility for Pt catalysts to reduce significantly the amount of precious metals Pt in parallel to maintain a high MOR activity and CO tolerance.

•Ultrafine PtNi alloy nanoparticles were uniformly deposited onto graphenes.•Their size can be controlled by changing Pt/Ni atomic ratio.•Ni modification can promote methanol oxidation at Pt surface significantly.A one-pot thermos-reduction strategy is developed to prepare ultrafine PtNi alloy nanoparticles (NPs), which are uniformly deposited onto reduced graphene oxides (RGOs) in the presence of polyvinylpyrrolidone (PVP). The size of PtNi NPs on RGOs can be tuned from 2.5 to 5.4 nm, after Ni was alloyed with Pt by Pt/Ni atomic ratio increased from 2:1 to 5:1. The electrochemical investigation demonstrates that Ni modification can promote the electrocatalytic activity of Pt catalysts on oxidation of methanol with a mass current density up to 1065 mA mg−1, which is 2.65 times that of Pt catalysts without Ni modification, and comparable to and even better than those of the Pt-based catalysts reported recently.

•Bimetallic AuPd nanoclusters are well distributed on graphitic carbon nitride sheets.•The one-pot aqueous method is simple and rapid, without any specific additives involved.•The nanocomposites display enlarged electrochemically active surface area.•The nanocomposites show enhanced electrocatalytic performances for ORR and HER.Herein, we developed a facile one-pot aqueous method to fabricate well-distributed bimetallic AuPd nanoclusters supported on graphitic carbon nitride (AuPd NCs/g-C3N4). The method is simple, rapid, without using any specific additives. The nanocomposites displayed enlarged electrochemically active surface area. The obtained nanocatalyst exhibited the more positive onset and half-wave potentials at 1.09 and 0.98 V (vs. NHE) for oxygen reduction reaction, respectively, along with the enhanced kinetic current density of 1.86 mA cm−2. Meanwhile, the catalyst showed the improved catalytic activity for hydrogen evolution reaction with the onset potential of −29 mV (vs. NHE) and small Tafel slope of 47 mV dec−1. These results demonstrated the improved electrocatalytic performance of the catalyst in contrast with commercial Pt/C (50%) and Pd/C (20%) catalysts.

•Pd nanoparticles were uniformly deposited on carbon nantubes.•Their size can be tuned by controlling Pd/Ir atomic ratio.•Ir modification can boost the catalytic activity of Pd on formic acid oxidation.One-pot thermos-reduction strategy was developed to prepare PdIr alloy nanoparticles (NPs) deposited on carbon nanotubes (CNTs). The obtained PdIr/CNT hybrids were characterized by transmission electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy and inductively coupled plasma-atom emission spectroscopy. The results show the dispersion of Pd NPs on CNTs can be improved by alloying with Ir, and the as-prepared PdIr NPs were uniformly deposited on CNTs with a tunable diameter from 2.3 to 4.2 nm. The electrochemical investigation exhibits Ir modification can boost the electrocatalytic activity of Pd catalysts on the formic acid oxidation with a mass current density up to 1620 mA mg−1, which is 7.7 times that of Pd catalysts without Ir modification, and comparable to and even better than those of the Pd-based catalysts reported recently.

A facile co-precipitation strategy is developed to prepare nickel hexacyanoferrate nanocubes (NiHCF NBs) supported on the reduced graphene oxide (rGO) in the presence of poly(diallyldimethylammonium chloride) (PDDA). The NiHCF NBs are uniformly deposited on the rGO by electrostatic interaction. Their size can be tuned from 10 nm to 85 nm by changing their content from 32.6% to 68.2%. Under the optimal condition, NiHCF/PDDA/rGO hybrids are composed of 51.4% NiHCF NBs with an average size of 38 nm. The specific capacitance of NiHCF/PDDA/rGO hybrids reaches up to 1320 F g−1 at a discharge density of 0.2 A g−1, more than twice that of the pure NiHCF, as well as slight capacitance decay by 15% at 0.2 A g−1 and excellent cycling stability with 87.2% of its initial capacitance after 10,000 discharge/charge cycles. More importantly, NiHCF/PDDA/rGO hybrids exhibit an ultrahigh energy density of 58.7 Wh kg−1 at the power density of 80 W kg−1. The superior storage energy performance of NiHCF/PDDA/rGO hybrids, such as high specific capacitance, good rate capacity and long cycling stability, positions them as a promising candidate for supercapacitor materials.

•Nickel hexacyanoferrate/carbon nantubes nanocables were prepared by co-precipitation.•Nickel hexacyanoferrate was covered on carbon nanotubes with controllable thickness.•Their energy storage performance is superior to pure Nickel hexacyanoferrate.•Their energy density is close to or better than those of conventional batteries.The transition metal hexacyanoferrate (MHCF, M represents as Fe, Co, Ni, et al), has been studied and applied intensively in biosensor, catalysts, ion exchanger, molecular magnets and gas storage, but as yet remains largely unexplored for electrochemical energy storage device. This study shows that NiHCF can be uniformly deposited into the matrix of poly(4-vinylpyridine) grafted onto multiwalled carbon nanotubes (MWCNTs), and forms coaxial NiHCF/MWCNT nanocables with MWCNTs as core and NiHCF as shell. A different NiHCF content was loaded onto MWCNTs, and their electrochemical behavior and capacitive performance were determined. The as-prepared NiHCF/P4VP-g-MWCNT hybrids can possess a huge specific capacitance up to 1035 F·g−1 at a discharge density of 0.05 A·g−1. These capacitance will decay by 10% at 25.6 A·g−1. They remain 92.7% of its initial capacitance at 2 A·g−1 after 10000 discharge/charge cycles. Their energy density is nearly 56.2 Wh·kg−1 at a power density of 10 W·kg−1. Their good electrochemical reversibility, high cyclic stability and excellent capacitive performance suggest a promising use as an advanced material for supercapacitors.

A facile wet chemical approach was developed to prepare ultralong PtIrTe nanotubes (NTs) using Te nanowires (NWs) as template. These PtIrTe NTs were made up of Pt nanodendrites uniformly arrayed on the surface of IrTe NTs and interweaved with each other to nanopores. Their morphology, structure, and composition were investigated by transition electron microscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy. As expected, these PtIrTe NTs catalysts show a larger surface area, a stronger CO tolerance, and a higher catalytic activity toward electrochemical oxidation of methanol relative to the commercial Pt catalysts due to the 1D porous core–shell structure and the modification of the electronic effect by Ir.Keywords: core−shell; electrocatalysis; methanol oxidation; nanotube

An easy and cost-effective approach was developed to deposit polyaniline (PANI) on a single graphitized multiwalled carbon nanotube (GMWCNT) by in situ chemical polymerization. The GMWCNTs were previously grafted with poly(4-vinylpyridine) (P4VP). The morphology and composition of the as-prepared PANI/P4VP-g–GMWCNT hybrids were characterized by the Fourier transform infrared spectroscopy, thermogravimetric analysis and transmission electron microscopy (TEM). The TEM images reveal these PANI/P4VP-g–GMWCNT hybrids possess a core shell structure and take shape as caterpillar. The storage energy performance was investigated by cyclic voltammetry, galvanostatic charge/discharge tests and electrochemical impedance spectroscopy. The PANI/P4VP-g–GMWCNT hybrids exhibit a high specific capacitance up to 1065 F g−1 and a long cyclic durability with 92.2% capacitance retention over 1000 cycling. A comparative study was carried out between PANI covered on the GMWCNTs with P4VP (PANI/P4VP-g–GMWCNT) and those without P4VP (PANI/GMWCNT). The PANI/P4VP-g–GMWCNT hybrids are superior to PANI/GMWCNT in term of specific capacitance, rate capability and cyclic stability due to their unique structure and full coverage of PANI on the GMWCNTs.

A novel amperometric nonenzymatic glucose sensor based on PtIr nanoparticles deposited on carbon nanotubes (PtIr/CNT hybrids) has been successfully fabricated and applied to the nonenzymatic glucose detection. Their electrochemical behavior toward the oxidation of glucose was compared with Pt nanoparticles deposited on carbon nanotubes (Pt/CNT hybrids) prepared with a similar procedure. In PtIr/CNT hybrids, PtIr nanoparticles were homogeneously dispersed on carbon nanotubes with an average diameter of 2.0 nm. Their size can be controlled by tuning the Pt/Ir ratio. In contrast, Pt nanoparticles are unevenly distributed on carbon nanotubes with an average diameter of 5.0 nm. The PtIr/CNT hybrids modified electrode shows a highly electroactive surface area, and displays a greatly enhanced electrocatalytic activity toward glucose oxidation. Chronoamperometry was applied to glucose detection in 0.2 M phosphate buffer solution (pH 7.4). The effect of the size of PtIr nanoparticles and the applied potential was investigated. The as-prepared PtIr/CNT hybrid based glucose sensor significantly shows a higher sensitivity, a lower detection limit and a wider linear range than those of Pt/CNT modified electrode. Moreover, Ir addition in Pt catalysts can enable the amperometric glucose detection with longer stability even in the presence of the interference such as ascorbic acid, uric acid, 4-acetamidophenol, creatinine and cholesterol. These results indicate that the PtIr/CNT hybrids are a promising candidate for a highly sensitive and selective nonenzymatic glucose sensor.Highlights► PtIr nanoparticles were uniformly deposited onto carbon nanotubes. ► The size of PtIr nanoparticles can be controlled by tuning the composition. ► These hybrids can be used as a nonenzyme sensor in glucose detection. ► This sensor shows a great enhancement in sensitivity, selectivity and stability.

Multiwalled carbon nanotubes (MWCNTs) are functionalized with phosphomolybdic acid (PMo) by ultrasonication. With the assistance of PMo, PtIr nanoparticles are homogeneously dispersed on the surface of MWCNTs. The size of PtIr nanoparticles can be controlled from 1.6 to 3.2 nm by tuning the composition of Pt catalysts. The composition of PtIr nanoparticles can be optimized at 4:1 Pt/Ir ratio, and as-prepared PMo/Pt4Ir1/MWCNT catalysts possess unique properties including a small size of PtIr nanoparticles, a high electroactive surface area and a large current density of methanol oxidation. For comparison, some Pt catalysts, Pt4Ir1/MWCNT and PMo/Pt/MWCNT, are also prepared in a controlled experiment. In the absence of PMo, PtIr nanoparticles are unevenly dispersed and aggregated on the surface of MWCNTs. Their average diameter is 3.1 nm, much larger than that of PtIr nanoparticles which are prepared in the presence of PMo (1.6 nm). This accounts for the difference in the catalytic activity of methanol and CO oxidation between Pt4Ir1/MWCNT and PMo/Pt4Ir1/MWCNT. On the other hand, the introduction of Ir makes PMo/Pt4Ir1/MWCNT catalysts superior to PMo/Pt/MWCNT catalysts in terms of a better CO-tolerance and a higher catalytic efficiency of methanol oxidation.

PtRu and Pt nanoparticles were deposited on the surface of multiwalled carbon nanotubes (MWCNTs) with the assistance of phosphomolybdic acid (PMo) by a one-pot hydrothermal reduction strategy. Transmission electron microscopy shows a high-density PtRu (or Pt) nanoparticles uniformly dispersed on the surface of the MWCNTs with an average diameter of 1.8 nm for PtRu nanoparticles and 2.4 nm for Pt nanoparticles. Moreover, the as-prepared PMo/PtRu/MWCNT and PMo/Pt/MWCNT electrocatalysts are highly electroactive for the electrochemical oxidation of methanol. Cyclic voltammograms show a high electrochemical surface area (ESA) and a large current density for methanol oxidation at the modified electrode by PMo/PtRu/MWCNT and PMo/Pt/MWCNT electrocatalysts. Electrochemical impedance spectroscopy reveals a high CO tolerance for PMo/PtRu/MWCNT and PMo/Pt/MWCNT electrocatalysts in the electrochemical catalysis of methanol oxidation. For comparison, PtRu/MWCNT and Pt/MWCNT electrocatalysts were prepared in control experiments without PMo. The results demonstrate that PtRu and Pt nanoparticles deposited on MWCNTs in the presence of PMo were superior to those on MWCNTs without PMo in several respects including: (1) a smaller size and a higher dispersion; (2) a higher ESA; (3) a larger current density for methanol oxidation; (4) a higher tolerance for CO poisoning.

NiHCFs nanoparticles are deposited onto the surface of multiwalled carbon nanotubes (MWCNTs) with a grafted poly(4-vinylpyridine). The as-prepared NiHCF/PV4P-g-MWCNTs composites are characterized by transition electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR), which confirms the presence of NiHCFs nanoparticles, and shows that NiHCFs nanoparticles are highly dispersed on the surface of MWCNTs in high density. Cyclic voltammograms (CVs) exhibit a great enhancement for NiHCFs/PV4P-g-MWCNTs composites in capacity and stability as ion exchanger by comparison with bulk NiHCF. The capacity for the electrodes modified with NiHCFs/PV4P-g-MWCNTs composites is 69.24 mC/cm−2 mg, after 100 cycles potential sweeping, these composites modified electrode retains its 98.5% ion-exchange capacity. These composites also exhibit a higher selectivity of for Cs+ over Na+ ions in high concentration of Na+ ion, which is confirmed by X-ray photoelectron spectroscopy (XPS).

Poly(4-vinylpyridine) (P4VB) was grafted to multiwalled carbon nanotubes (MWCNTs) by an in situ polymerization. This grafted polymer plays two roles in the synthesis of Prussian Blue (PB)/MWCNT composites: (1) a stabilizer to protect PB nanoparticles from aggregation; (2) a linker to anchor these nanoparticles on the surface of MWCNTs. The size of PB nanoparticles deposited on MWCNTs can be controlled by in site layer-by-layer coordination of Fe3+ and [Fe(CN)6]4− ions in aqueous solution. The as-prepared PB/P4VP-g-MWCNT composites were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray powder diffraction, which revealed that these PB nanoparticles were uniformly distributed on the surface of MWCNTs, and grew upon layer-by-layer assembly. A potential use of PB/P4VP-g-MWCNT composites was demonstrated as an electrocatalyst used in the electrochemical detection of l-cysteine. The as-prepared electrodes modified with PB/P4VP-g-MWCNT composites showed two reversible redox waves assigned to a fast surface-controlled processes. The analytical performance for l-cysteine detection is associated with the load of PB nanoparticles onto MWCNTs. In an optimal experiment, for these as-prepared electrodes, their detection limit of l-cysteine can be measured as low as 0.01 μM with a sensitivity 778.34 nA μM−1 cm−2.Highlights► Carbon nanotubes were grafted with poly(4-vinylpyridine). ► Prussian blue nanoparticles were deposited on carbon nanotubes by complextion. ► The size of these nanoparticles can be controlled by layer-by-layer assembly. ► The compoistes show a superior catalytic activity to the oxidation of L-cysteine. ► The efficiency is dependent on the capacity of Prussian blue nanoparticles loaded.

A green, one-step method for synthesis of graphene–Au nanoparticles (graphene–AuNPs) was introduced in this article, using an environmentally benign hexamethylenetetramine (HMTA) as reducing and stabilizing agent. HMTA slowly was hydrolyzed to generate aldehyde ammonia to reduce graphene oxides (GO) and hydrogen tetrachloroaurate (Au precursor). The structure and composition of the graphene–AuNPs nanocomposites were studied by means of ultraviolet visible (UV) absorption spectra, X-ray photoelectron spectroscopy (XPS) and Transmission electron microscopy (TEM). The AuNPs are well-dispersed on graphene nanosheets in narrow size range. The nanocomposites have excellent electrocatalytical properties for catalytic reduction of O2 and H2O2.Highlights► HMTA is an environmentally friendly reducing and stabilizing agent. ► GO and Au precursor can be reduced to graphene–AuNPs nanocomposites by HMTA in one-step. ► The AuNPs are well-dispersed on graphene nanosheets in narrow size range. ► The graphene–AuNPs nanocomposites modified GCE showed excellent electrocatalytic activity toward O2 and H2O2.

Multiwalled carbon nanotubes (MWCNTs) were grafted with poly(4-vinylpyridine) (PV4P) in aqueous solution by in situ free radical polymerization of 4-vinylpyridine. The as-prepared PV4P-g-MWCNTs hybrids can load phosphotungstic acid (PW) on a large scale by electrostatic interaction, which was characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The as-prepared PWs/PV4P-g-MWCNTs hybrids were modified onto a carbon glassy electrode. Cyclic voltammograms (CVs) show that the electrochemical behavior of the modified electrode follows a four-one-electron surface-confined process of Keggin-type PWs. The modified electrode can be used as a nitrite sensor. The comparison of CVs shows that the response current of nitrite reduction at the electrode modified with PWs/PV4P-g-MWCNTs hybrids is 15 times higher than that of PWs/MWCNTs hybrids in a control experiment at 0.65 V (vs. AgCl). The amperometric i–t   curve for the electrode modified with PWs/PV4P-g-MWCNTs hybrids exhibits a linear concentration of NO2− ranged from 1.2 to 17.5 μM with a detection limit of 0.2 μM.Highlights► Carbon nanotubes was grafted with poly(4-vinylpyridine). ► Phosphotungstic acid was deposited onto carbon nanotubes with this polymer linker. ► This deposition is highly uniform and large scale. ► These phosphotungstic acid/carbon nanotubes hybrids can be used as nitrite sensor. ► Its linear concentration is 1.2 to 17.5 μM with a detection limit of 0.2 μM.

The fabrication and notably improved performance of composite electrodes based on the nanocomposite of diphenylalanine peptide-covered multiwalled carbon nanotube (PP–MWCNT) is described. The synthesis of the nanocomposite of PP–MWCNT is a self-assembly process of diphenylalanine peptide (PP) along carbon nanotube (MWCNT) via aromatic stacking interaction combined with hydrogen bond of diphenylalanine peptide. PP–MWCNT modified electrode was fabricated by a simple casting method, and studied with cyclic voltammetry (CV) and chronoamperometry. PP–MWCNT modified electrode showed a high, direct and unmediated response to β-reduced coenzyme nicotinamide adenine dinucleotide (NADH) at a potential of 0.600 V (vs. SCE), which had reduced the overvoltage of NADH oxidation by 0.200 V in comparison with the bare electrode. Furthermore, the current response of NADH at PP–MWCNT modified electrode is about five times higher than that of the bare electrode. Thus, PP–MWCNT provides a new candidate for fabrication of biosensor based on β-coenzyme nicotinamide adenine dinucleotide (NAD+)-dependent dehydrogenases. Herein, an ethanol biosensor was prepared by crosslinking ethanol dehydrogenase (ADH), bovine serum albumin (BSA) and PP–MWCNT onto the electrode. The ethanol biosensor exhibited a good linearity ranged from 30 μM to 700 μM with a high sensitivity of 30.00 nA/μM cm−2 and with a low detection limit of 12 μM.Research highlights► An electrochemical active nanocomposite of diphenylalane dipeptide/multiwalled carbon nanotubes has been prepared on the basis of noncovalent assembly. ► The as-prepared nanocomposite can offer a remarkable decrease of the overvoltage of NADH oxidation, which makes it available in a high-sensitive ethanol biosensor.

A facile and wet-chemical approach was employed to control synthesis of self-organizing, hyperbranched nanoporous Au microsheet with high quality in bulk quantity. This method produced nanoporous Au microsheets with a thickness of 7–15 nm. The microsheets were composed of irregularly interconnected planar Au nanoplates with interstices, i.e. nanopores of 10–50 nm. And the nanoporous Au microsheets were enveloped in 10–30 nm thick polyaniline (PANI) sheaths. The morphology of the nanostructured Au composites could also be easily tuned by changing the concentration of aniline and chlorauric acid. The dendritic and epitaxial growth of nanoporous Au microsheet was believed as the diffusion-limited process confined in the lamellar emulsion phase through self-assembly of aniline and dodecylsulfate. The solution reaction proceeded at a mild condition (room temperature and aqueous solutions), and less toxic reagents were employed instead of extreme toxic and corrosive chemicals.

Multiwalled carbon nanotubes (MWCNTs) are functionalized with phosphomolybdic acid (PMo) by ultrasonication. With the assistance of PMo, PtIr nanoparticles are homogeneously dispersed on the surface of MWCNTs. The size of PtIr nanoparticles can be controlled from 1.6 to 3.2 nm by tuning the composition of Pt catalysts. The composition of PtIr nanoparticles can be optimized at 4:1 Pt/Ir ratio, and as-prepared PMo/Pt4Ir1/MWCNT catalysts possess unique properties including a small size of PtIr nanoparticles, a high electroactive surface area and a large current density of methanol oxidation. For comparison, some Pt catalysts, Pt4Ir1/MWCNT and PMo/Pt/MWCNT, are also prepared in a controlled experiment. In the absence of PMo, PtIr nanoparticles are unevenly dispersed and aggregated on the surface of MWCNTs. Their average diameter is 3.1 nm, much larger than that of PtIr nanoparticles which are prepared in the presence of PMo (1.6 nm). This accounts for the difference in the catalytic activity of methanol and CO oxidation between Pt4Ir1/MWCNT and PMo/Pt4Ir1/MWCNT. On the other hand, the introduction of Ir makes PMo/Pt4Ir1/MWCNT catalysts superior to PMo/Pt/MWCNT catalysts in terms of a better CO-tolerance and a higher catalytic efficiency of methanol oxidation.