Nanocomposites of palladium nanoparticle-loaded mesoporous carbon nanospheres for the electrochemical determination of hydrogen peroxide

Electrochemical sensor for rutin detection based on N-doped mesoporous carbon nanospheres and graphene

A new electrochemical sensor shows great sensing performance to rutin and high selectivity towards even 13 interfering species and realizes detection of rutin in real samples such as human serum.

A glassy carbon electrode modified with a nanocomposite prepared from Pd/Al layered double hydroxide and carboxymethyl cellulose for voltammetric sensing of hydrogen peroxide

A Pd/Al layered double hydroxide/carboxymethyl cellulose nanocomposite (CMC@Pd/Al-LDH) was fabricated using carboxymethyl cellulose as a green substrate via co-precipitation method. The synthesized nanocomposite was characterized using different methods such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray powder diffraction, transmission electron microscopy, and electrochemical techniques. A glassy carbon electrode (GCE) was then modified with the suspended composite to obtain an electrochemical sensor for hydrogen peroxide (H₂O₂). The voltammetric (cathodic) current of the modified GCE was measured at -380 mV (vs. Ag/AgCl), at the scan rate of 50 mV.s^-1. Results show a linear dynamic range of 1 to 120 μM, and a 0.3 µM limit of detection (at S/N = 3). Intraday and interday relative standard deviations are in the ranges of 4.9-5.4% and 6.8-7.3%, respectively. The sensor was applied for the determination of H₂O₂ in basil extracts, milk, and spiked river water samples. The recoveries are between 96.60 and 102.30%. Graphical abstractA Pd/Al layered double hydroxide/carboxymethyl cellulose nanocomposite (CMC@Pd/Al-LDH) was fabricated via co-precipitation method and was characterized using scanning electron microscopy, Energy-dispersive X-ray spectroscopy, X-ray powder diffraction, transmission electron microscopy and electrochemical techniques. CMC@Pd/Al-LDH was used to fabricate H₂O₂ electrochemical sensor.

Recent Trends on Electrochemical Sensors Based on Ordered Mesoporous Carbon

The past decade has seen an increasing number of extensive studies devoted to the exploitation of ordered mesoporous carbon (OMC) materials in electrochemistry, notably in the fields of energy and sensing. The present review summarizes the recent achievements made in field of electroanalysis using electrodes modified with such nanomaterials. On the basis of comprehensive tables, the interest in OMC for designing electrochemical sensors is illustrated through the various applications developed to date. They include voltammetric detection after preconcentration, electrocatalysis (intrinsically due to OMC or based on suitable catalysts deposited onto OMC), electrochemical biosensors, as well as electrochemiluminescence and potentiometric sensors.

Bioapplications of Electrochemical Sensors and Biosensors

Recent progress in the electrochemical field enabled development of miniaturized sensing devices that can be used in biological settings to obtain fundamental and practical biochemically relevant information on physiology, metabolism, and disease states in living systems. Electrochemical sensors and biosensors have demonstrated potential for rapid, real-time measurements of biologically relevant molecules. This chapter provides an overview of the most recent advances in the development of miniaturized sensors for biological investigations in living systems, with focus on the detection of neurotransmitters and oxidative stress markers. The design of electrochemical (bio)sensors, including their detection mechanism and functionality in biological systems, is described as well as their advantages and limitations. Application of these sensors to studies in live cells, embryonic development, and rodent models is discussed.

Synthesis of Pd/SBA-15 catalyst employing surface-bonded vinyl as a reductant and its application in the hydrogenation of nitroarenes

Pd/SBA-15 was synthesised through the reduction of PdCl2 by surface bonded vinyl. The catalyst was effective for the hydrogenation of aromatic nitro compounds under mild conditions.

Fabrication of a sensitive amperometric sensor for NADH and H2O2 using palladium nanoparticles-multiwalled carbon nanotube nanohybrid

Palladium nanoparticles decorated multiwalled carbon nanotubes (PdNPs-MWCNTs) were synthesized and simply cast on the surface of a glassy carbon electrode (GCE) to prepare an amperometric sensor. The fabricated sensor (PdNPs-MWCNTs/GCE) showed excellent electrocatalytic activity towards NADH and H2O2 oxidation and H2O2 reduction. A fast, linear and highly sensitive response was observed for NADH in the concentration range between 0.1 and 200 μM with a detection limit (S/N=3) of 32 nM. Also, the sensor exhibited fast and sensitive responses (<2 s) towards H2O2. The sensitivity and detection limit for H2O2 at the operating potential of +0.35 V were 167 nA μM(-1)cm(-2) and 1.2 μM, respectively and better than those obtained at the operating potential of -0.25 V (68 nA μM(-1)cm(-2) and 14 μM). Moreover, further modification of the proposed sensor by glucose oxidase led to the fabrication of a glucose biosensor with satisfactory performance.

Fast preparation of MoS2 nanoflowers decorated with platinum nanoparticles for electrochemical detection of hydrogen peroxide

MoS₂ nanoflowers decorated with Pt nanoparticles show enhanced performances for electrochemical H₂O₂ sensing.

Highly porous Pd nanostructures and reduced graphene hybrids: excellent electrocatalytic activity towards hydrogen peroxide

A new approach has been developed for highly porous Pd nanostructure–graphene hybrids as efficient electrocatalysts towards reduction of H₂O₂.

A Simple Green Synthesis of Palladium Nanoparticles with Sargassum Alga and Their Electrocatalytic Activities Towards Hydrogen Peroxide

This study presents the synthesis of palladium nanoparticles (PdNPs) using the extract derived from the marine alga, Sargassum bovinum, collected from Persian Gulf area. Water-soluble compounds that exist in the marine alga extract were the main cause of the reduction of palladium ions to Pd nanoparticles. The basic properties of PdNPs produced in this method were confirmed by UV-visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX) analysis, and Fourier transform infrared spectroscopy (FTIR). TEM confirmed the monodispersed and octahedral shape of PdNPs within the size ranges from 5 to 10 nm. Catalytic performance of the biosynthetic PdNPs was investigated by electrochemical reduction of hydrogen peroxide (H2O2). PdNP-modified carbon ionic liquid electrode (PdNPs/CILE) was developed as a nonenzymatic sensor for the determination of hydrogen peroxide. Amperometric measurements showed that PdNPs/CILE is a reliable sensor for the detection of hydrogen peroxide in the range of 5.0 μM-15.0 mM with a sensitivity of 284.35 mAmM(-1) cm(-2) and a detection limit of 1.0 μM. Moreover, PdNPs/CILE exhibits a wide linear range, high sensitivity and selectivity, and excellent stability for the detection of H2O2 in aqueous solutions.

PdCo alloy nanoparticle-embedded carbon nanofiber for ultrasensitive nonenzymatic detection of hydrogen peroxide and nitrite

PdCo alloy nanoparticle-embedded carbon nanofiber (PdCo/CNF) prepared by electrospinning and thermal treatment was employed as a high-performance platform for the determination of hydrogen peroxide and nitrite. The as-obtained PdCo/CNF were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Electrochemical impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry were employed to investigate the electrochemical behaviors of the resultant biosensor. The proposed PdCo/CNF-based biosensor showed excellent analytical performances toward hydrogen peroxide (detection limit: 0.1 μM; linear range: 0.2 μM-23.5 mM) and nitrite (detection limit: 0.2 μM; linear range: 0.4-30 μM and 30-400 μM). The superior analytical properties could be attributed to the synergic effect and firmly embedment of well-dispersed PdCo alloy nanoparticles. These attractive electrochemical properties make this robust electrode material promising for the development of effective electrochemical sensors.

Fabrication of novel nitrogen-doped graphene-hollow AuPd nanoparticle hybrid films for the highly efficient electrocatalytic reduction of H2O2

Hollow AuPd (hAuPd) alloy nanoparticles (NPs) were prepared through simultaneous reduction of HAuCl4 and Na2PdCl4 using Co NPs as sacrificial template (i.e., reductant). Then, the hAuPd NPs were assembled on nitrogen-doped graphene (NG) to prepare an NG-hAuPd hybrid film. The obtained NG-hAuPd composite showed higher electrocatalytic activity toward the reduction of H2O2, compared with graphene-hAuPd hybrid, NG-solid AuPd hybrid, and hAuPd NPs. The enhanced performance was related to the hollow structure of hAuPd NPs and the synergistic effect between NG and hAuPd NPs. Under optimum conditions, the NG-hAuPd hybrid film showed a linear response to H2O2 in the range of 0.1-20 μM, with a sensitivity of 5095.5 μA mM(-1) cm(-2)and a comparable detection limit of 0.02 μM (S/N = 3). These results demonstrated that the NG-hAuPd composite was a promising electrocatalytic material for constructing sensors, etc.

Hydrogen peroxide sensitive hemoglobin-capped gold nanoclusters as a fluorescence enhancing sensor for the label-free detection of glucose

A novel label-free fluorescent probe based on blue-emitting gold nanoclusters capped by hemoglobin for the direct detection of glucose is presented.

Electrochemical immunosensor based on hydrophilic polydopamine-coated prussian blue-mesoporous carbon for the rapid screening of 3-bromobiphenyl

A sensitive electrochemical immunosensor for 3-bromobiphenyl (3-BBP) detection was constructed by employing a new polydopamine coated prussian blue-mesoporous carbon (PDOP/PB/CMK-3) nanocomposite as the substrate platform and multi-horseradish peroxidase-double helix carbon nanotubes-secondary antibody (multi-HRP-DHCNTs-Ab2) as the signal label. PB/CMK-3 was firstly successfully in-situ synthesized with the aid of the CMK-3 reduction, which was characterized by transmission electron microscope (TEM), infrared spectroscopy (IR), X-ray diffraction (XRD) and N2 adsorption-desorption analysis. By using PDOP/PB/CMK-3 as the substrate, it can effectively enhance the specific surface for antigen loading due to the three-dimensional structure of the nanocomposites, while large amount of PB that fixed inside or outside the pore of CMK-3 successfully improved the electrochemical response and the PDOP film can provide a biocompatible environment to maintain the activity of antigen availability. Under the optimized conditions, the proposed immunosensor shows a good current response to 3-BBP in a linear range from 5 pM to 2 nM with a detection limit of 2.25 pM. In addition, the specificity, reproducibility and stability of the immunosensor were also proved to be acceptable, indicating its potential application in environmental monitoring.

Nanopatterning palladium surface layers through electrochemical deposition and dissolution of zinc in ionic liquid

Cracklike nanopatterned palladium surface layers have been produced by a green chemistry method based on in situ electrochemical deposition-dissolution of zinc (Zn-ECDD) in an ionic liquid bath. During the cathodic process, reactive Zn was electrochemically deposited onto a polycrystalline Pd substrate. During the subsequent anodic process, Zn was removed from the substrate through electrochemical dissolution. Scanning electron microscope (SEM) measurements showed that repetitive Zn-ECDD mediated by potential cycles results in the nanopatterning of Pd surface layers, characterized by uniform crack appearance with well-distributed concave spacings separated by nanowidth cracks. Energy-dispersive X-ray microscopy (EDX) studies revealed that the nanopatterned surface layers chemically contain a small amount of Zn. A mechanism based on the development of stress induced by the Zn-ECDD on Pd surfaces was proposed to be responsible for the nanopatterning of Pd surface layers. Electrochemical oxidation of formic acid and reduction of nitrite were studied as model reactions to demonstrate potential applications of the nanopatterned Pd electrode to electrocatalysis and electrochemical determination of environmental contaminants. Highly improved electrochemical responses were obtained on the nanopatterned Pd for the two reactions, compared to the untreated Pd.