A Portable Microelectrochemical Sensor Based on Potentiostatic Polarization-Treated and Laser-Induced Graphene for the Simultaneous Determination of Ascorbic Acid, Dopamine, and Uric Acid.

Maintaining normal biomolecular levels in the human body plays a crucial role in controlling various diseases. In this work, we designed a portable microelectrochemical sensor based on laser-induced graphene (LIG) for the simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). A simple electrode surface modification strategy, potentiostatic polarization in an alkali solution, was applied to functionalize the LIG surface with the aim of enhancing the LIG electrocatalytic activity, conductivity, and wettability.

Re-understanding of SERS for General and Standardized Quantitative Analysis.

We proposed two physical concepts, i.e., an intramolecular relative cross section (RCS) and an intermolecular relative scattering ability (RSA), to re-understand and re-describe surface-enhanced Raman scattering (SERS) and established a general SERS quantification theory.

Portable Copper-Based Electrochemical SERS Sensor for Point-of-Care Testing of Paraquat and Diquat by On-Site Electrostatic Preconcentration.

With the advent of portable Raman spectrometers, the deployment of surface-enhanced Raman spectroscopy (SERS) in point-of-care testing (POCT) has been initiated. Within any analytical framework employing SERS, the acuity and selectivity inherent to the SERS substrate are of paramount importance. In this article, we utilize in situ electrochemical passivation technology to fabricate CuI passivation film, which serves as a flexible copper-based SERS substrate.

Development of a selective electrochemical microsensor based on molecularly imprinted polydopamine/ZIF-67/laser-induced graphene for point-of-care determination of 3-nitrotyrosine.

3-nitrotyrosine (3-NT) is a biomarker closely associated with the early diagnosis of oxidative stress-related disorders. The development of an accurate, cost-effective, point-of-care 3-NT sensor holds significant importance for self-monitoring and clinical treatment. In this study, a selective, sensitive, and portable molecularly imprinted electrochemical sensor was developed.

Highly Sensitive Detection of Formaldehyde by Laser-Induced Graphene-Coated Silver Nanoparticles Electrochemical Sensing Electrodes.

Formaldehyde (HCHO) poses a grave threat to human health because of its toxicity, but its accurate, sensitive, and rapid detection in aqueous solutions remains a major challenge. This study proposes a novel electrochemical sensor composed of a graphene-based electrode that is prepared via laser induction technology. The precursor material, polyimide, is modified via the metal ion exchange method, and the detective electrode is coated with graphene and silver nanoparticles.

Design of a versatile and selective electrochemical sensor based on dummy molecularly imprinted PEDOT/laser-induced graphene for nitroaromatic explosives detection.

Considering the formidable explosive power and human carcinogenicity of nitroaromatic explosives, the implementation of an accurate and sensitive detection technology is imperative for ensuring public safety and monitoring post-blast environmental contamination. In the present work, a versatile and selective electrochemical sensor based on dummy molecularly imprinted poly (3,4-ethylenedioxythiophene)/laser-induced graphene (MIPEDOT/LIG) was successfully developed and the specific detection of multiple nitroaromatic explosives was realized in the single sensor. The accessible and nontoxic trimesic acid (TMA) and superior 3, 4-ethylenedioxythiophene (EDOT) were selected as the dummy-template and the functional monomer, respectively.

Responses of human gingival fibroblasts to superhydrophilic hydrogenated titanium dioxide nanotubes.

Soft tissue integration is critical for the long-term retention of dental implants. The surface properties including topography and wettability can impact soft tissue sealing. In our work, a thermal hydrogenation technique was applied to modify anodized titanium dioxide nanotubes (TNTs).

Robust quantitative SERS analysis with Relative Raman scattering intensities.

Robust quantitative analysis methods are very attractive but challenging with surface-enhanced Raman scattering (SERS) technique till now. Quantitative analysis methods using absolute Raman scattering intensities tend to desire very critical reproducibility of SERS substrates and consistency of testing conditions, as batch differences and inhomogeneity of SERS substrates as well as the fluctuation of measuring parameters placed challenging obstacles. Relative Raman scattering intensities, on the other hand, can release the adverse interferences mentioned above and provide effective and robust information as it is independent of the reproducibility of SERS substrates.

Using Atomic Force Microscopy to Measure Thickness of Passive Film on Stainless Steel Immersed in Aqueous Solution.

Employing atomic force microscopy (AFM) to measure passive film thickness on stainless steel (SS) in aqueous solution is proposed. SUS304 austenite and SUS329J4L duplex SS samples partly covered by gold were set in a minicell. To remove the original film, the SS surface but gold was etched using dilute sulfuric acid.

Slanted Ag-Al alloy nanorods arrays for highly active and stable surface-enhanced Raman scattering substrates.

Aluminum has been established as an earth-abundant and low-cost alternative to gold and silver for plasmonic applications. Particularly, aluminum largely tends to combines with oxygen compared with silver. Here, a simple glancing angle deposition technique is presented to prepare Ag-Al alloy nanorods (NRs) with a small amount of aluminum.

Highly stable and active SERS substrates with Ag-Ti alloy nanorods.

Silver (Ag) nanostructures have been intensively studied as one of the most promising surface-enhanced Raman scattering (SERS) substrates; however, their practical applications have been limited by the chemical instability with regard to oxidation, sulfuration and etching of Ag. Therefore, designing and fabricating highly active Ag nanostructures with high SERS stability has been recognized as an important research area. Herein, Ag-Ti alloy nanorods (Ag-Ti alloy NRs) are designed and fabricated by the oblique angle deposition (OAD) method to protect Ag.

Quantification of trace chemicals in unknown complex systems by SERS.

The chemical quantitative analysis at trace level has been widely explored by means of various techniques. While it still remains challenging to achieve ultrasensitive but facile, rapid, and inexpensive detection methods. In this paper, the possibility of employing surface-enhanced Raman scattering technique on a portable Raman system for rapid and accurate quantitative analysis of target chemicals in unknown systems was investigated.

Effects of hydrogenated TiO nanotube arrays on protein adsorption and compatibility with osteoblast-like cells.

Background: Modified titanium (Ti) substrates with titanium dioxide (TiO) nanotubes have broad usage as implant surface treatments and as drug delivery systems.

Methods: To improve drug-loading capacity and accelerate bone integration with titanium, in this study, we hydrogenated anodized titanium dioxide nanotubes (TNTs) by a thermal treatment. Three groups were examined, namely: hydrogenated TNTs (H-TNTs, test), unmodified TNTs (air-TNTs, control), and Ti substrates (Ti, control).

H2 sensing properties of pd modified WO3-Fe2O3 nanostructured composite films prepared by amorphous W-Fe dealloying.

Tungsten trioxide nanopetal with Fe2O3 composite films were synthesized by dealloying the W-Fe alloy film in HCl aqueous solution; nano-Pd particles were directly electrochemical deposited on the surface of dealloying films in a micro-emulsion system and following thermal oxidation in air. The structure, morphology, chemical composition and quality of the prepared WO3 nanopetal with Fe2O3 composite films were characterized by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. The results showed that the thickness of the WO3 nanopetals were less than 50 nm, which were monoclinic phase after controlled thermal oxidation process, and the nano-Pd particles were evenly dispersed on the WO3 film surface with controlled diameters ranging from 20 to 40 nm.

A novel NO2 sensor based on TiO2 nanotubes array with in-situ Au decoration.

Au decorated TiO2 nanotubes array was successfully fabricated on a Ti-Au alloy via an electrochemical anodization process. The crystal phase and microstructure of the TiO2 nanotubes array were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. Au particles were well distributed among TiO2 nanotubes and acted as the catalyst.

Preliminary investigation of solution diffusive behavior on V-doped TiO2 nanotubes array by electrochemical impedance spectroscopy.

V-doped TiO2 nanotubes array was successfully fabricated on a Ti-V alloy via an electrochemical anodization process. The crystal phase and surface morphology of the nanostructured film were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The solution diffusive behavior on TiO2 nanotubes was investigated by electrochemical impedance spectroscopy (EIS) analysis in an aqueous electrolyte containing 0.

A novel CO sensor based on the point contact between Pd decorated TiO2 nanotubes array.

To obtain a high sensitive CO sensor, a new nanostructure based on the point contact between Pd decorated TiO2 nanotubes was proposed in this paper. TiO2 nanotubes array was fabricated on titanium wire by electrochemical anodic oxidation, and Pd catalytic nanoparticles were modified by the micro-emulsion electrochemical deposition. The surface morphology was characterized by field emission scanning electron microscopy (FE-SEM), and CO sensitivity of the point contact between TiO2 nanotubes was investigated through the current-voltage (I-V) characteristic measurement.

[Research of the photoelectrocatalysis degradation of methylene blue of TiO2 nanotube array films annealed in oxygen atmospheres].

Well-aligned and uniform titanium dioxide nanotube arrays were fabricated in situ on titanium substrate by electrochemical anodic oxidation. SEM images indicate that the TiO2 nanotubes are well organized into high-density uniform arrays,with diameter ranging in size from 70 to 100 nm. The XRD patterns show that the sample fabricated by anodic oxidation is amorphous without being annealed.

Fabrication and hydrogen sensing properties of interlinked ribbon-like TiO2 films.

Interlinked ribbon-like TiO2 films were prepared by micro-arc oxidation (MAO) process and subsequent chemical-treatment of titanium substrate. The chemical-treatment included two steps: firstly, alkali treatment was performed on the surface of the porous TiO2 films, and then the samples were ion-exchanged in acid aqueous solution. The phase and microstructure of the samples were characterized by XRD, FE-SEM and TEM.

Enhanced hydrogen production on porous TiO2 nanotube arrays.

Well aligned TiO2 nanotube arrays have been synthesized via anodization in an NH4F and ethylene glycol electrolyte; the resulting carbon-entrained films were treated by oxygen and argon microwave plasma. It was found that as-prepared amorphous TiO2 nanotubes can be easily crystallized into anatase at temperature lower than 150 degrees C. Carbon can be effectively eliminated in oxygen plasma and a new secondary porosity was emerged.

Preparation and visible light photocatalytic properties of (Er, La, N)-codoped TiO2 nanotube array films.

TiO2 nanotube array films were prepared by in-situ liquid phase transformation and deposition of anodic aluminum oxidation template films with (NH4)2TiF6 dilute solution; and the (Er, La, N)-codoped films were fabricated by impregnation with rare earth elements of Er and La following by heat treatment in flow ammonia. Obviously enhanced photocatalytic degradation of organic dye was obtained by codoped TiO2 under visible light irradiation compared with undoped TiO2 film, and the increase of photocatalytic performance of as-prepared TiO2 was attributed to the enlargement of light absorbency ranging from upconversed UV to red-shifted visible light up to 600 nm.

Hydrogen sensitivity performance of Pd doped SnO2 nanostructured film fabricated by spray pyrolysis.

The present investigation dealt with the fabrication of H2 gas sensor based on Pd doped SnO2. Porous SnO2 nanostructured film were fabricated by spray pyrolysis route using tin chloride pentahydrate (SnCl4.5H2O) solution as starting material, and PdCl2 as a dopant.

Processing of copper converter slag for metal reclamation. Part I: Extraction and recovery of copper and cobalt.

Clean processing of copper converter slag to reclaim cobalt and copper could be a challenge. An innovative and environmentally sound approach for recovering valuable metals from such a slag has been developed in the present study. Curing the slag with strong sulphuric acid, without re-smelting or roasting as practiced currently in the industry, render it accessible to leaching, and more than 95% of cobalt and up to 90% of copper was extracted together with iron by water leaching, leaving silica behind in a residue.

Processing of copper converter slag for metals reclamation: Part II: mineralogical study.

Chemical and mineralogical characterizations of a copper converter slag, and its products obtained by curing with strong sulphuric acid and leaching with hot water, were carried out using ore microscopy, scanning electronic microscopy with energy dispersive spectrometry, wave-length dispersive X-ray fluorescence spectrometry, X-ray diffractometry and chemical phase analysis, which provided necessary information to develop a new process for treating such slag and further understanding of the chemical and mineralogical changes in the process.