Fengxia Wu

Unprecedented metal-free 3D porous carbonaceous electrodes for full water splitting

Earth-abundant, active and stable water splitting electrocatalysts operating in the same electrolyte at all pH values is important for many renewable energy conversion processes. We report here the first carbon nanomaterials-based metal-free water splitting electrocatalyst. The nitrogen, phosphorus and oxygen tri-doped porous graphite carbon@oxidized carbon cloth (ONPPGC/OCC) electrocatalyst can be prepared by a simple cost-effective method using aniline, phytic acid and OCC as precursors. Being a robust integrated three-dimensional porous bifunctional electrode, ONPPGC/OCC enables a high-performance basic water electrolyzer with 10 mA cm−2 at a cell voltage of 1.66 V. Additionally, this electrode offers excellent catalytic performance and durability under both neutral and acidic conditions.

Sensitive detection of alkaline phosphatase by switching on gold nanoclusters fluorescence quenched by pyridoxal phosphate

In this work, we designed highly sensitive and selective luminescent detection method for alkaline phosphatase using bovine serum albumin functionalized gold nanoclusters (BSA-AuNCs) as the nanosensor probe and pyridoxal phosphate as the substrate of alkaline phosphatase. We found that pyridoxal phosphate can quench the fluorescence of BSA-AuNCs and pyridoxal has little effect on the fluorescence of BSA-AuNCs. The proposed mechanism of fluorescence quenching by PLP was explored on the basis of data obtained from high-resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS), UV-vis spectrophotometry, fluorescence spectroscopy, fluorescence decay time measurements and circular dichroism (CD) spectroscopy. Alkaline phosphatase catalyzes the hydrolysis of pyridoxal phosphate to generate pyridoxal, restoring the fluorescence of BSA-AuNCs. Therefore, a recovery type approach has been developed for the sensitive detection of alkaline phosphatase in the range of 1.0-200.0U/L (R2 =0.995) with a detection limit of 0.05U/L. The proposed sensor exhibit excellent selectivity among various enzymes, such as glucose oxidase, lysozyme, trypsin, papain, and pepsin. The present switch-on fluorescence sensing strategy for alkaline phosphatase was successfully applied in human serum plasma with good recoveries (100.60-104.46%), revealing that this nanosensor probe is a promising tool for ALP detection.

Concave and duck web-like platinum nanopentagons with enhanced electrocatalytic properties for formic acid oxidation

Pt-branched structures featuring concave and duck web-like nanopentagons (CWPNP), with surfaces enclosed by {111} facets, high-energy {110} and {554} facets, multiple twin boundaries, duck web-like edges and inherent anisotropic branches are herein reported. The unique chemisorption properties and reducing capacities of tri-n-propylamine and oleylamine, as well as the inhibition of oxidative etching of the twin defects by the exclusion of chloride ions contribute to the formation of Pt CWPNP. Pt CWPNP exhibited unprecedented electrocatalytic activities, high antipoisoning activity and durability in formic acid oxidation reaction (FOR) in comparison to commercial Pt/C and Pt black, and thus is a promising catalyst for the FOR. The excellent FOR performance of Pt CWPNP is attributed to the least poisoned {111} facets, active sites by high-energy facets, multiple twin boundaries, duck web-like edges and inherent anisotropic branches composed of 1D nanowires. It is anticipated that this study will offer a new approach for the design of surface structure-controlled FOR electrocatalysts.

Increasing Electrochemiluminescence Intensity of a Wireless Electrode Array Chip by Thousands of Times Using a Diode for Sensitive Visual Detection by a Digital Camera.

Both a wireless electrochemiluminescence (ECL) electrode microarray chip and the dramatic increase in ECL by embedding a diode in an electromagnetic receiver coil have been first reported. The newly designed device consists of a chip and a transmitter. The chip has an electromagnetic receiver coil, a mini-diode, and a gold electrode array. The mini-diode can rectify alternating current into direct current and thus enhance ECL intensities by 18 thousand times, enabling a sensitive visual detection using common cameras or smart phones as low cost detectors. The detection limit of hydrogen peroxide using a digital camera is comparable to that using photomultiplier tube (PMT)-based detectors. Coupled with a PMT-based detector, the device can detect luminol with higher sensitivity with linear ranges from 10 nM to 1 mM. Because of the advantages including high sensitivity, high throughput, low cost, high portability, and simplicity, it is promising in point of care testing, drug screening, and high throughput analysis.

3D Printed Rotating Acentric Binary-disk Electrode

Rotating ring-disk electrode (RRDE) is a generator-collector electrochemical system widely used as an electroanalytical and kinetic device. However, RRDEs are costly and difficult to fabricate, particularly when the electrode material is fragile, small, and scarce. Taking advantage of readily available 3D printing technology an alternative generator-collector system was developed: rotating acentric binary-disk electrode (RABDE). RABDE consists of two close acentric disk electrodes arranged in a cylindrical matrix so that the line connecting their centers is perpendicular to radius of the device passing through the center of generator electrode. In contrast to RRDE that is based on radial flow velocity for mass transfer between the generator and the collector, RABDE mostly takes advantage of the larger tangential flow velocity. RABDE thus exhibits higher current densities than RRDE for a same rotation rate and evidences much better electroanalytical performances. These increased performances were tested and quantified using typical analytes: potassium ferricyanide system, copper ion system, and oxygen reduction reaction in alkaline solution.