Xiaoxia Lv

Large Surface Area Ordered Porous Carbons via Nanocasting Zeolite 10X and High Performance for Hydrogen Storage Application

We report the preparation of ordered porous carbons for the first time via nanocasting zeolite 10X with an aim to evaluate their potential application for hydrogen storage. The synthesized carbons exhibit large Brunauer-Emmett-Teller surface areas in the 1300-3331 m(2)/g range and pore volumes up to 1.94 cm(3)/g with a pore size centered at 1.2 nm. The effects of different synthesis processes with pyrolysis temperature varied in the 600-800 °C range on the surface areas, and pore structures of carbons were explored. During the carbonization process, carbons derived from the liquid-gas two-step routes at around 700 °C are nongraphitic and retain the particle morphology of 10X zeolite, whereas the higher pyrolysis temperature results in some graphitic domains and hollow-shell morphologies. In contrast, carbons derived from the direct acetylene infiltration process have some incident nanoribbon or nanofiber morphologies. A considerable hydrogen storage capacity of 6.1 wt % at 77 K and 20 bar was attained for the carbon with the surface area up to 3331 m(2)/g, one of the top-ranked capacities ever observed for large surface area adsorbents, demonstrating their potential uses for compacting gaseous fuels of hydrogen. The hydrogen capacity is comparable to those of previously reported values on other kinds of carbon-based materials and highly dependent on the surface area and micropore volume of carbons related to the optimum pore size, therefore providing guidance for the further search of nanoporous materials for hydrogen storage.

Towards the determination of sulfonamides in meat samples: A magnetic and mesoporous metal-organic framework as an efficient sorbent for magnetic solid phase extraction combined with high-performance liquid chromatography

A magnetic, mesoporous core/shell structured Fe3O4@JUC-48 nanocomposite was synthesized and employed as a magnetic solid phase extraction (MSPE) sorbent for the determination of trace sulfonamides (SAs) in meat samples. The synthesized nanocomposite was characterized by X-ray diffraction, Fourier transform infrared spectra, transmission electron microscopy, scanning electron microscopy, Brunner-Emmet-Teller, and vibrating sample magnetometry; the Fe3O4@JUC-48 nanocomposite exhibited a distinctive morphology, large surface area, high magnetism, open adsorption sites, and high chemical stability. By combining the optimized MSPE conditions with high performance liquid chromatography diode array detection, an accurate and sensitive method for the determination of 5 SAs, including sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethazine (SMZ), and sulfamethoxypyridazine (SMP), was developed. The method exhibited good linearity in the range of 3.97-1000ng/g with R ranging from 0.9991 to 0.9994, high sensitivity with LODs ranging from 1.73 to 5.23ng/g, adequate recoveries between 76.1 and 102.6% with low relative standard deviations ranging from 2.1 to 6.4%, and high precision with RSD<4.5%. The Fe3O4@JUC-48 magnetic nanocomposite is a promising sorbent for the rapid and efficient extraction of SAs from complex biological samples such as chicken, pork, and shrimp.

Super-hydrophobic Silver-Doped TiO 2 @ Polycarbonate Coatings Created on Various Material Substrates with Visible-Light Photocatalysis for Self-Cleaning Contaminant Degradation

In the present work, a facile and efficient fabrication method has been developed for creating super-hydrophobic coatings of silver-doped TiO2@polycarbonate (TiO2 (Ag)@PC) on the substrates of different materials with photocatalytic self-cleaning performances simply by the “dipping and drying” process. The substrates were first patterned with glue and then deposited with the dopamine-capped TiO2 (Ag)@PC (DA-TiO2 (Ag)@PC) nanocomposites, followed by the further etching with dimethylbenzene. The so prepared super-hydrophobic E-DA-TiO2(Ag)@PC coatings could present the lotus leaf-like porous architectures, high adhesion stability, and especially the visible-light photocatalysis for organic contaminant degradation, thus promising the wide outdoor and indoor applications like water proofing, metal erosion protection, and surface self-cleaning.

Fluorimetric Mercury Test Strips with Suppressed “Coffee Stains” by a Bio-inspired Fabrication Strategy

A fluorimetric Hg2+ test strip has been developed using a lotus-inspired fabrication method for suppressing the “coffee stains” toward the uniform distribution of probe materials through creating a hydrophobic drying pattern for fast solvent evaporation. The test strips were first loaded with the model probes of fluorescent gold-silver nanoclusters and then dried in vacuum on the hydrophobic pattern. On the one hand, here, the hydrophobic constraining forces from the lotus surface-like pattern could control the exterior transport of dispersed nanoclusters on strips leading to the minimized “coffee stains”. On the other hand, the vacuum-aided fast solvent evaporation could boost the interior Marangoni flow of probe materials on strips to expect the further improved probe distribution on strips. High aqueous stability and enhanced fluorescence of probes on test strips were realized by the hydrophilic treatment with amine-derivatized silicane. A test strips-based fluorimetry has thereby been developed for probing Hg2+ ions in wastewater, showing the detection performances comparable to the classic instrumental analysis ones. Such a facile and efficient fabrication route for the bio-inspired suppression of “coffee stains” on test strips may expand the scope of applications of test strips-based “point-of-care” analysis methods or detection devices in the biomedical and environmental fields.

Silver Nanoclusters Encapsulated into Metal–Organic Frameworks with Enhanced Fluorescence and Specific Ion Accumulation toward the Microdot Array-Based Fluorimetric Analysis of Copper in Blood

Silver nanoclusters (AgNCs) were first coated with bovine serum albumin (BSA) and then encapsulated into porous metal-organic frameworks of ZIF-8 by the protein-mediated biomineralization process. Unexpectedly, the fluorescence intensities of the yielded AgNCs-BSA@ZIF-8 nanocomposites were discovered to be continuously enhanced during each of the BSA coating and ZIF-8 encapsulation steps. Compared to common AgNCs, greatly improved photostability and storage stability of AgNCs could also be expected. More importantly, having benefited from the ZIF-8 shells, the prepared nanocomposites could possess the specific accumulation and sensitive response to Cu2+ ions, resulting in the rational quenching of their fluorescence intensities. Moreover, AgNCs-BSA@ZIF-8 nanocomposites were coated onto the hydrophobic arraying slides toward a microdots array-based fluorimetric method for the fast and sensitive evaluation of Cu2+ ions. It was discovered that the developed fluorimetric strategy could ensure the high-throughput analysis of Cu2+ ions in wide pH range, and especially some harsh and high-salt media. It can allow for the detection of Cu2+ ions in blood with the concentrations ranging from 4.0 × 10-4 to 160 μM, thus serving as a new copper detection candidate to be widely applied in clinical test, food safety, and environmental monitoring fields.

An electroanalysis strategy for glutathione in cells based on the displacement reaction route using melamine-copper nanocomposites synthesized by the controlled supermolecular self-assembly

An electroanalysis strategy has been developed for probing glutathione (GSH) separately in hela and yeast cells based on the displacement reaction route using melamine-copper (MA-Cu) nanocomposites. Herein, MA-Cu nanocomposites were initially synthesized by the controlled supermolecular self-assembly process showing various morphological structures depending on the MA-to-Cu ratios used. It was discovered that the electrodes modified with rod-like MA-Cu nanocomposites could achieve the stable electrochemical output of solid-state CuCl at a low potential, which might circumvent the possible interference from co-existing electroactive substances in complicated backgrounds like cells. More importantly, the yielded CuCl signals would decrease selectively induced by GSH through the specific Cu-GSH interaction that would trigger the displacement of CuCl into non-electroactive complex. The MA-Cu nanorods-modified electrodes can allow for the detection of GSH with the concentrations linearly ranging from 0.010 to 300.0 μM. Subsequently, the feasibility of the developed electroanalysis strategy was demonstrated for the evaluation of GSH separately in the extractions of hela and yeast cells, promising the wide applications in the clinical and food analysis fields.

Synergic TiO2 photocatalysis and guanine photoreduction for silver deposition amplification: An ultrasensitive and high-throughput visualized colorimetric analysis strategy for Anthrax DNAs in blood using wettable microwells array

An ultrasensitive and high-throughput visualized colorimetric method has been initially developed with a wettable microwells array for probing guanine base-containing anthrax DNAs in blood based on silver deposition amplified by the synergic TiO2 photocatalysis and guanine photoreduction under visible light. Hydrophilic microwells were first created on the hydrophobic slides to yield the wettable microwells array, on which photocatalytic titanium dioxide (TiO2) nanoparticles were deposited with dopamine (DA) to yield TiO2@DA for anchoring single strand DNA (ssDNA) capture probes without guanine bases. After the hybridization of the targeted anthrax DNAs, exonuclease I (Exo I) was introduced into the microwells to selectively digest the unhybridized ssDNA probes. The silver deposition was further conducted by the synergic photocatalysis of TiO2@DA and photoreduction of guanine bases of anthrax DNAs, thus achieving the amplified silver signals for the visualized colorimetric assays. Moreover, benefitting from the wettability feature of the hydrophilic-hydrophobic interfaces of the microwells array so fabricated, DNA analytes could be accumulated from the sample droplets through the condensing enrichment process to realize the ultrasensitive detection, in addition to circumventing any crossover contaminants between the sample droplets. The developed visualized colorimetric method with the microwells array was subsequently applied for probing anthrax DNAs in blood with levels down to 1.0 fM. DNAs with single-base and double-base mutations could also be identified accurately. Importantly, such a biosensing design route of a wettable microwells array, in combination with the photocatalytic silver deposition and specific Exo I-catalytic probe digestion, may promise extensive applications for the high-throughput, ultrasensitive, and selective detection of guanine-containing DNA targets with ultra-trace levels in complicated samples like blood.

Superwettable Microwell Arrays Constructed by Photocatalysis of Silver-Doped-ZnO Nanorods for Ultrasensitive and High-Throughput Electroanalysis of Glutathione in Hela Cells

Superwettable microwell arrays were constructed for the first time by the synergic photocatalysis of silver-doped-ZnO (Ag-ZnO) nanorods patterned on indium tin oxide (ITO) electrodes for electroanalysis of glutathione (GSH) in hela cells through the signal output of AgCl electrochemistry. The newly prepared Ag-ZnO nanorods with high photocatalysis were dispersed into an octadecyltrichlorosilane (OTS) matrix to be deposited onto ITO substrates, yielding superhydrophobic Ag-ZnO-OTS coatings. Superhydrophilic microwells were further created by the Ag-ZnO photocatalysis under UV irradiation to produce Ag-ZnO microwell arrays featuring the superwettability profile. The resulting Ag-ZnO microwell-modified ITO electrodes were employed further for electroanalysis of GSH through solid-state AgCl electrochemistry, in which the specific Ag-GSH interactions would trigger a rational decrease in the sharp AgCl peak currents at the potential approaching zero. Moreover, benefitting from the superwettability feature, the microwells on the ITO electrodes could facilitate the condensing enrichment of GSH analytes from the sample droplets, achieving improved analysis sensitivity. The as-developed electroanalysis strategy was subsequently demonstrated for the detection of GSH in hela cell supernatant with levels down to about 27.30 pM. Additionally, this synergic photocatalysis-based preparation route can be tailored for the large-scale fabrication of various array platforms with the superwettability feature for high-throughput and sensitive biological analysis.