Xiaoyue Yue

One-pot synthesis of multifunctional magnetic ferrite–MoS2–carbon dot nanohybrid adsorbent for efficient Pb(II) removal

Herein, we demonstrate a one-pot solvothermal synthetic method for fabricating MFe2O4 (M = Mn, Co)–MoS2–carbon dot (CD) nanohybrid composites (MnFMC, CoFMC) with excellent Pb(II) removal ability. Detailed characterization through SEM, XRD, UV-vis spectra, fluorescence spectra and VSM confirmed the formation of the nanohybrid composites. The adsorption behavior of the as-prepared nanohybrids was systematically studied using kinetic and equilibrium experiments, and the adsorption mechanism was further revealed using XPS and FTIR. Taking advantage of the cation substitution of abundant functional groups on the surface of CDs and MFe2O4 nanoparticles, as well as the large surface of available MoS2 for enhancing the sequestration of target metal-pollutants, the as-prepared composites exhibit high adsorption performances (588.24 mg g−1 for MnFMC and 660.67 mg g−1 for CoFMC) and show preferential Pb(II) sorption behavior with a high level concentration of competing cations (Ca(II)/Mg(II)). Moreover, these nanohybrid adsorbents exhibit excellent reusability, lower the effluent Pb(II) contents down to the ppb level, which satisfies the drinking water standard recommended by the World Health Organization, and are promising candidates for water purification.

DNA-mediated gold nanoparticle signal transducers for combinatorial logic operations and heavy metal ions sensing

Herein, the structure of two DNA strands which are complementary except fourteen T-T and C-C mismatches was programmed for the design of the combinatorial logic operation by utilizing the different protective capacities of single chain DNA, part-hybridized DNA and completed-hybridized DNA on unmodified gold nanoparticles. In the presence of either Hg(2+) or Ag(+), the T-Hg(2+)-T or C-Ag(+)-C coordination chemistry could lead to the formation of part-hybridized DNA which keeps gold nanoparticles from clumping after the addition of 40 μL 0.2M NaClO4 solution, but the protection would be screened by 120 μL 0.2M NaClO4 solution. While the coexistence of Hg(2+), Ag(+) caused the formation of completed-hybridized DNA and the protection for gold nanoparticles lost in either 40 μL or 120 μL NaClO4 solutions. Benefiting from sharing of the same inputs of Hg(2+) and Ag(+), OR and AND logic gates were easily integrated into a simple colorimetric combinatorial logic operation in one system, which make it possible to execute logic gates in parallel to mimic arithmetic calculations on a binary digit. Furthermore, two other logic gates including INHIBIT1 and INHIBIT2 were realized to integrated with OR logic gate both for simultaneous qualitative discrimination and quantitative determination of Hg(2+) and Ag(+). Results indicate that the developed logic system based on the different protective capacities of DNA structure on gold nanoparticles provides a new pathway for the design of the combinatorial logic operation in one system and presents a useful strategy for development of advanced sensors, which may have potential applications in multiplex chemical analysis and molecular-scale computer design.

Au Promoted Nickel–Iron Layered Double Hydroxide Nanoarrays: A Modular Catalyst Enabling High-Performance Oxygen Evolution

Oxygen evolution reaction (OER) plays a key role in various energy conversion and storage technologies, such as water electrolysis, regenerative fuel cells, and rechargeable metal-air batteries. However, the slow kinetics of OER limit the performance and commercialization of such devices. Herein, we report on NiFe LDH@Au hybrid nanoarrays on Ni foam for much enhanced OER. By hybridization of electronegative Au and NiFe LDH with intrinsic remarkable OER catalytic activity, this modular electrode could drive an overall ultrahigh-performance and robust OER in base with the demand of overpotentials of only 221, 235, and 270 mV to afford 50, 100, and 500 mA cm-2, respectively. Also, it exhibits superior catalytic activity and durability toward OER in 30 wt % KOH.

Highly Sensitive and Selective Determination of Tertiary Butylhydroquinone in Edible Oils by Competitive Reaction Induced “On–Off–On” Fluorescent Switch

As one of most common synthetic phenolic antioxidants, tertiary butylhydroquinone (TBHQ) has received increasing attention due to the potential risk for liver damage and carcinogenesis. Herein, a simple and rapid fluorescent switchable methodology was developed for highly selective and sensitive determination of TBHQ by utilizing the competitive interaction between the photoinduced electron transfer (PET) effect of carbon dots (CDs)/Fe(III) ions and the complexation reaction of TBHQ/Fe(III) ions. This novel fluorescent switchable sensing platform allows determining TBHQ in a wider range from 0.5 to 80 μg mL(-1) with a low detection limit of 0.01 μg mL(-1). Furthermore, high specificity and good accuracy with recoveries ranging from 94.29 to 105.82% in spiked edible oil samples are obtained with the present method, confirming its applicability for the trace detection of TBHQ in a complex food matrix. Thus, the present method provides a novel and effective fluorescent approach for rapid and specific screening of TBHQ in common products, which is beneficial for monitoring and reducing the risk of TBHQ overuse during food storage.

Highly Specific and Sensitive Determination of Propyl Gallate in Food by a Novel Fluorescence Sensor

Propyl gallate (PG), one of the most widely used synthetic phenolic antioxidants in edible oil, cookies and fried food, has received extensive concern due to its possible toxic effects on human health. Herein, a novel fluorescence analytical method is firstly proposed to sensitively and selectively determine propyl gallate (PG) by utilizing the unique fluorescence quenching property of organic molybdate complex (OMC) formed by the specific reaction between MoO42- and PG to g-C3N4 nanosheets. Under the optimum conditions, the developed fluorescence sensor allows highly sensitive detection of PG in a wide range from 0.5 to 200 μg mL-1 with a detection limit of 0.11 μg mL-1, and possesses excellent specificity and good recoveries. All the analytical results indicate the present method provides an effective approach for rapid detection of PG in common products, which is beneficial for monitoring and reducing the risk of overuse of PG.