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The chaperone protein heat shock protein 60 (HSP60) is considered a tumor promoter in several types of primary human tumors, where it orchestrates a broad range of survival programs. Curcumin (CCM) is well-established to exhibit several anticancer properties with an excellent safety profile. Our previous study showed that CCM suppresses extracellular HSP60 expression, which is typically released by activated microglia, and acts as an inflammatory factor by binding to Toll-like receptor 4 (TLR-4) on the cell membrane. The present study assessed whether CCM exerted its anti-neuroglioma effects on U87 cells via inhibition of HSP60/TLR-4 signaling, similar to that in microglia. The results demonstrated that CCM significantly inhibited the viability and invasive capacity of neuroglioma U87 cells as evidenced by a Cell Counting Kit-8 assay. Western blotting and ELISA results showed that CCM decreased the expression of HSP60 and its transcriptional factor, heat shock factor 1, and reduced HSP60 release. Accordingly, TLR-4, as the target of HSP60, and its downstream signaling proteins myeloid differentiation primary response 88 (MYD88), NF-κB, inducible nitric oxide synthase and cytokines IL-1β and IL-6 were downregulated by CCM. The expression levels of apoptotic factors associated with NF-κB activation, including TNF-α and caspase-3 were increased in U87 cells by CCM treatment, while p53 expression, a tumor suppressor, was shown to be decreased. Based on the results of the present study, CCM may exert its anti-tumor effects in U87 cells by inhibiting the HSP60/TLR-4/MYD88/NF-κB pathway and inducing tumor cell apoptosis. Thus, CCM may be used as a potential therapy for the clinical treatment of neuroglioma.

Recombinant interferon-α (rIFN-α) has been widely used for treating viral infections. However, the clinical efficacy of unmodified rIFN-α is limited due to small molecular size and rapid clearance from circulation. In this study we developed a novel strategy for half-life extension of porcine IFN-α (PoIFN-α) by fusion to the immunoglobulin (Ig)-binding C2 domain of streptococcal protein G (SPG). The coding sequences for PoIFN-α6 and SPG C2 domain, with a tobacco etch virus (TEV) protease recognition sequence introduced at the 5-end, were cloned into an elastin-like polypeptide (ELP) fusion expression vector and expressed as an ELP-PoIFNα-C2 fusion protein. After optimization of the conditions for soluble protein expression and purification, the fusion protein was purified to more than 90% purity by two rounds of inverse transition cycling (ITC) in the presence of 0.5% Triton X-100. After cleavage with self-aggregating peptide ELK-16-tagged tobacco etch virus protease, the protease was removed by quick centrifugation and PoIFNα-C2 protein was recovered by an additional round of ITC with 98% purity. Western blotting analysis showed that PoIFNα-C2 protein had the specific affinity for pig IgG binding. The antiviral assay showed that PoIFNα-C2 protein had potent antiviral activities against vesicular stomatitis virus and porcine pseudorabies virus. After single intravenous or subcutaneous injection into rats, PoIFNα-C2 protein showed 16- or 4-fold increase in serum half-life with significantly improved bioavailability.

The accurate and reproducible large-scale production of catalyst layers containing low-cost, abundant electrocatalysts gains in importance. Herein, pivotal factors are discussed that need to be considered when a combined inkjet printing and photonic curing platform is used as a promising fabrication method for catalyst layers based on a model low-cost catalyst, i.e., nitrogen-doped reduced graphene oxide supported cobalt oxide nano sheets (Co3O4/N-rGO), specifically prepared to formulate an inkjet ink. The ink is stable for weeks and can reproducibly be printed with piezoelectric printheads. Ink composition and printing parameters are optimized to achieve high-resolution printing and good adhesion on glassy carbon substrates. Polyvinylpyrrolidone and ethyl cellulose are used as catalyst stabilizers in the ink and must be removed through thermal post-processing to avoid a decrease of the electrical conductivity of the catalyst layer and a degradation of the catalytic activity of the Co3O4 nanocrystals. Conventional slow oven curing (i.e., hours) and photonic curing with a Xe flash lamp (seconds) are compared to generate temperatures above 400 °C under ambient conditions. Both techniques can increase the size of the Co3O4 nanocrystals from ∼7 nm up to ∼15 nm. Photonic curing with pulses above 2 J·cm–2 shot energy density initiates the reduction of the oxidation states of cobalt from (II,III) to (II). Residues and side products of polymeric stabilizers can be found using photonic curing pulses below 10 J·cm–2. This work highlights the advances made in digital printing and post-processing for catalyst layer production and demonstrates the importance of proper design of the ink, the printing and the post-processing for the large-scale production of catalyst layers for the ORR based on low-cost materials. The findings can be transferred to other metal and mixed metal oxide nanocatalysts.

Photoionic cell is a facile concept for direct solar energy conversion and storage based on dye-quencher couples. We propose a system based on dye modified amphiphilic mesoporous graphene (APG) and cobalt EDTA as a photoionic cell. Upon light irradiation, the dyes are excited and quenched by cobalt EDTA in aqueous solution to form oxidized cobalt EDTA and reduced dyes that are hydrophobic. Solar energy is then converted into electrochemical energy in the form of the oxidized cobalt EDTA in aqueous solutions and reduced dyes in APG. Compared to organic phase usually used for photoionic cells, the usage of APG can lead to increased amount of dye molecules in the photoionic cells, and can achieve approximately 100% separation of the reduced dyes from the oxidized cobalt EDTA for long term energy storage.

N,N′-diisobutyloxycarbonyl-N″,N‴-(1,3-propylene)-bisthiourea ( L ) and its silver(I) and gold(I) complexes were designed and synthesized. Treatment of 1,3-propanediamine with the isothiocyanate i PrCH 2 OC(O)NCS yielded bisthiourea L with over 90% yield. Treatment of L with AgNO 3 in CH 3 CN afforded coordination polymer {[Ag( L )(NO 3 )·CH 3 CN]} n ( 1 ) with layer structure, while with HAuCl 4 in CH 3 CN resulted in reduction of Au 3+ to Au + to yield molecular [Au( L )Cl] ( 2 ). Ligand L and complexes 1 and 2 were fully characterized by IR, 1 H NMR, UV–Vis, cyclic voltammetry and element analysis. The X-ray diffraction analysis displays that the bisthiourea L behaves as sulfur donor to coordinate to Ag and Au atom with μ 3- (S, μ 2 -S′,S′) and μ 2 -S, S′ coordination mode in 1 and 2 , respectively.

In this paper, a novel surfactant, N -butoxypropyl- S -[2-(hydroxyimino) propyl] dithiocarbamate ester (BOPHPDT) was first synthesized and introduced as a flotation collector for copper minerals. The micro and bench-scale flotation results demonstrated BOPHPDT exhibited superior flotation performance for chalcopyrite in comparison with xanthates and excellent selectivity against pyrite, and the preferable pH values for its attachment to chalcopyrite surfaces were 4–8. Adsorption thermodynamics and kinetics elucidated that BOPHPDT adsorption on to chalcopyrite was a spontaneously endothermic chemisorption process. The results of in situ scanning electrochemical microscopy (SECM) and zeta potential showed that BOPHPDT might anchor on the positively charge sites of chalcopyrite surfaces to form new species. Fourier transform infrared (FTIR) spectra further elucidated that BOPHPDT might react with the Cu atoms of chalcopyrite surfaces through its C N OH and NH C( S) groups. The double chelating groups and multiple hydrophobic chains of BOPHPDT, rendered it to possess excellent affinity and hydrophobicity for improving copper minerals flotation.

Glycosidic linkage structure, physical-chemical properties and in vitro digestibility of pyrodextrins prepared using different reaction conditions were characterized. Intensification of reaction condition promoted starch hydrolysis and transglucosidation until the solubility of pyrodextrin reached 100%. New branch points were formed including α-1,2, β-1,2, β-1,4, β-1,6 and α-1,6 linkages. Majority of the branch points was α-1,6 and β-1,6 linkages which in together accounted for more than 70% of the total branches. The degree of branching increased at intensified reaction conditions and plateaued at approximately 24%. Exhaustively hydrolyzing pyrodextrin by α-amylase and amyloglucosidase significantly decreased the degree of α-1,4 but not α-1,6 linkages. The retained α-1,4 and α-1,6 linkages were probably protected from enzyme hydrolysis by the non-starch linkages due to steric hindrance. The resistant starch content was positively correlated with the degree of branching of pyrodextrin. The decreased in vitro digestibility of pyrodextrin was attributed to the formation of new glycosidic linkages.

In this paper, a novel surfactant, O-isopropyl-S-[2-(hydroxyimino) propyl] dithiocarbonate ester (IPXPO) was synthesized and first introduced as a collector, and its flotation behavior and adsorption mechanism to chalcopyrite were investigated by micro-flotation, adsorption thermodynamics and kinetics, in situ scanning electrochemical microscopy (SECM), Zeta potential and FTIR spectroscopy. IPXPO exhibited superior flotation performances to chalcopyrite in comparison to pyrite and preferably attached on to chalcopyrite surfaces at pH 4–9. The adsorption IPXPO on to chalcopyrite was agreed well with Langmuir isotherm and pseudo-second-order equation, and the adsorption ΔH (enthalpy change), ΔS (entropy change), ΔG (free energy change) and Ea (activation energy) were 70.44 kJ/mol, 332.23 J/mol/K, −28.49 kJ/mol (298 K) and 22.85 kJ/mol respectively, inferring a spontaneously endothermic chemisorption process. Zeta potential and in situ SECM images demonstrated that IPXPO might anchor on the positively charged sites of chalcopyrite surface to form new species. FTIR spectra further elucidated that the IPXPO Cu surface complexes were produced probably by reaction of C S and C N OH groups of IPXPO with copper atoms to form Cu S, Cu N and Cu O bonds on chalcopyrite surfaces. IPXPO's unique properties, such as two chelating groups and characteristic adsorption manner, rendered it to be a good collector for chalcopyrite flotation.

The most engineering application for the molecular self-assembly of sulfydryl compounds on solid surfaces is froth flotation. In this work, the hydrophobic mechanism of 3-hexyl-4-amino-1,2,4-triazole-5-thione (HATT) on chalcopyrite (CuFeS2) was first investigated by in situ atomic force microscopy (AFM), in situ scanning electrochemical microscopy (SECM), time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), contact angle and flotation tests. In situ AFM imaging elucidated that HATT might aggregate on chalcopyrite surface to form self-assembled monolayers. In situ SECM images confirmed the weakened tip current of chalcopyrite region after HATT adsorption. On the self-assembly layers, HATT bound overwhelmingly with copper atoms to form a five-membered-ring Cu(I)-HATT surface complex, accompanying with the reduction of cupric to cuprous. HATT anchored on chalcopyrite surfaces through its exocyclic S and N atoms of 4-amino-1,2,4-triazole-5-thione group and left its hexyl group towards aqueous solutions, resulting in an enhanced surface hydrophobicity to improve the flotation recovery of copper minerals. This fundamental understanding inspired by in situ approaches will promote the innovation and development of novel flotation surfactants.

A novel electrochemical sensing platform based on nitrogen-doped graphene (N-G)/nickel tetrasulfonated phthalocyanine (NiTsPc) nanocomposites has been developed for selective determination of dopamine (DA). NiTsPc was immobilized on N-G matrix via π-π interaction, while N-G provided a compatible microenvironment for NiTsPc to enhance electron transfer and to retain its electrocatalytic activity as well. The N-G/NiTsPc nanocomposite was characterized by using transmission electron microscopy (TEM), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV). The proposed modified electrode presented superior catalytic efficiency for DA in the presence of ascorbic acid (AA) and uric acid (UA) owing to the synergistic effect of N-G and NiTsPc. The sensors also exhibited a wide linear range from 1 × 10 − 7 to 2 × 10 − 4 M and a limit of detection as low as 100 nM with high sensitivity of 88.9 μA mM − 1 .

A highly active, stable and inexpensive electrocatalyst, nanosized-Mo2C/reduced-graphene-oxide (nanoMo2C/RGO), is developed for the hydrogen evolution reaction, which is of vital importance for environment concerns and the energy crisis. The nanocomposite catalyst is synthesized by a novel strategy through the facile calcination of a pre-prepared organic–inorganic hybrid MoOx–amine precursor of sub-nanosized periodic structure. The intercalation of the amine in the organic–inorganic precursor leads to the synchronous reduction of MoOx–amine to Mo2C and GO to RGO in an inert atmosphere, and thus nano-Mo2C/RGO is facilely synthesized with highly monodisperse Mo2C nanoparticles (3–5 nm) as well as the reduced graphene. The remarkable structures and features are demonstrated to be the determinants for accelerating the interfacial electrocatalytic reaction with low charge-transfer resistance and high interfacial capacitance. This study should provide a new perspective on the development of efficient noble-metal-free electrocatalysts in the fields of energy conversion and storage.

The hydrophobic mechanism of 3-hexyl-4-amino-1, 2, 4-triazole- 5-thione (HATT) to malachite (Cu2CO3(OH)2) was investigated by contact angle, micro-flotation, zeta potential, Fourier transform infrared (FTIR) spectroscopy, time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectra (XPS). After HATT modification, the wettability of malachite surfaces was changed from hydrophilicity to hydrophobicity, and its zeta potential moved to more negative values, demonstrating that HATT might adsorb on the positively charged copper species via its anionic amino-triazole-thione group with leaving its hexyl group against malachite surfaces. The hydrophobized malachite particles attached selectively to air bubbles and subsequently moved to the pulp surface with the bubbles. FTIR and ToF-SIMS indicated that HATT might chemisorb on malachite surfaces by formation of Cu-S and Cu-N bonds with the breakage of S-H bond in HATT thiol tautomer. XPS further elucidated that a five- membered-ring HATT-Cu(I) surface complex was formed by bonding the exocyclic S and N atoms of HATT with the copper atom on malachite surfaces.

In this paper, a novel surfactant, 3-hexyl-4-amino-1,2,4-triazole-5-thione (HATT) is first introduced as a collector for chalcopyrite flotation. Its flotation behavior and adsorption mechanism to chalcopyrite has been evaluated by micro-flotation tests, and zeta potential, FTIR spectra and adsorption quantity measurements. The results demonstrate that HATT exhibited excellent flotation performances to chalcopyrite at pH 4–8. The adsorption of HATT on to chalcopyrite agrees well with the pseudo-second-order model and Langmuir isotherm, and is a spontaneously endothermic chemisorption process. FTIR spectra and zeta potential analyses further imply that chalcopyrite might chemisorb HATT by formation of HATT–copper surface complexes.

Macromolecules have a strong tendency to interact with each other in solution to form a supramolecular structure through various secondary binding forces. In this study, nucleobase-containing templates poly(9-(4-vinylbenzyl)adenine) (PS AH) and poly(1-(4-vinylbenzyl)cytosine) (PS CH) are prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization. Vinylbenzyl thymine (MS T) is polymerized in the presence of these two nucleobase-containing templates. MS T shows higher affinities toward the template PS AH compared with the template PS CH. In accordance with the Watson-Crick pairing principle, thymine forms hydrogen bonding (H-bonding) with adenine, but not between thymine and cytosine. A complex is formed when PS AH is used as template which indicates that there is a template polymerization of nucleobase complexes via molecular recognition.

Herein, NiCrP amorphous alloy coatings were prepared on copper substrates by electrodeposition. The aim of this paper is to replace Cr6+ with Cr3+ to prepare NiCrP amorphous alloy coating, which can reduce environmental pollution. By studying the influence of pH, temperature (T), current density (DK), and CrCl3 concentration on the structure, surface morphology, composition, and corrosion resistance of the alloy coatings, the optimum bath formulation and process parameters were determined as follows: 25 g&middot, L&minus, 1 NiSO4&middot, 6H2O, 100 g&middot, 1 CrCl3&middot, 6H2O, 20 g&middot, 1 NaH2PO2&middot, H2O, 80 g&middot, 1 Na3C6H5O7&middot, 2H2O (sodium citrate), 40 g&middot, 1 H3BO3, 50 g&middot, 1 NH4Cl, 1 g&middot, 1 KF, 5 g&middot, 1 C7H5O3NS (saccharin), 0.05 g&middot, 1 C12H25SO4Na (sodium dodecyl sulfate), and 40 mL&middot, 1 HCOOH and T: 30 &deg, C, DK: 15 A&middot, dm&minus, 2, and pH: 3.5, respectively. NiCrP amorphous alloy coatings with high corrosion resistance were prepared under the abovementioned conditions. The crystal cells of the coating surface are uniform and fine. The corrosion resistance of the NiCrP amorphous alloy coatings was characterized by polarization curves, electrochemical impedance spectroscopy, and an immersion corrosion test and compared with that of the NiP amorphous alloy coating. The results show that Ni91.9P8.1 and Ni83.5Cr8.3P8.2 corrosion potential and corrosion current density are &minus, 0.68, &minus, 0.44 V, and 36, 7 &mu, A&middot, cm&minus, 2 in 3.5 wt.% NaCl, respectively. With Ni91.9P8.1 and Ni83.5Cr8.3P8.2, the maximum weight loss is 61.67 and 15.42 mg&middot, 2 in a 1 mol&middot, 1 HCl, respectively. The corrosion resistance of the NiCrP amorphous alloy coatings in 3.5 wt.% NaCl and 1 mol&middot, 1 HCl solutions is better than that of the NiP alloy coating.

Background Vascular endothelial growth factor (VEGF) is commonly overexpressed in a variety of tumor types including lung cancer. As a key regulator of angiogenesis, it promotes tumor survival, growth, and metastasis through the activation of the downstream protein kinase B (AKT) and extracellular signal-regulated kinase (ERK 1/2) activation. The VEGF promoter contains a 36 bp guanine-rich sequence (VEGFq) which is capable of forming quadruplex (four-stranded) DNA. This sequence has been implicated in the down-regulation of both basal and inducible VEGF expression and represents an ideal target for inhibition of VEGF expression. Results Our experiments demonstrate sequence-specific interaction between a G-rich quadruplex-forming oligonucleotide encoding a portion of the VEGFq sequence and its double stranded target sequence, suggesting that this G-rich oligonucleotide binds specifically to its complementary C-rich sequence in the genomic VEGF promoter by strand invasion. We show that treatment of A549 non-small lung cancer cells (NSCLC) with this oligonucleotide results in decreased VEGF expression and growth inhibition. The VEGFq oligonucleotide inhibits proliferation and invasion by decreasing VEGF mRNA/protein expression and subsequent ERK 1/2 and AKT activation. Furthermore, the VEGFq oligonucleotide is abundantly taken into cells, localized in the cytoplasm/nucleus, inherently stable in serum and intracellularly, and has no effect on non-transformed cells. Suppression of VEGF expression induces cytoplasmic accumulation of autophagic vacuoles and increased expression of LC3B, suggesting that VEGFq may induce autophagic cell death. Conclusion Our data strongly suggest that the G-rich VEGFq oligonucleotide binds specifically to the C-rich strand of the genomic VEGF promoter, via strand invasion, stabilizing the quadruplex structure formed by the genomic G-rich sequence, resulting in transcriptional inhibition. Strand invading oligonucleotides represent a new approach to specifically inhibit VEGF expression that avoids many of the problems which have plagued the therapeutic use of oligonucleotides. This is a novel approach to specific inhibition of gene expression.

Three meso-tetraaryl substituted N -5 sapphyrins were synthesized by a facile synthetic route from the corresponding open-chain pentapyrroles in high yield using acetic acid as the solvent and catalyst. Each compound was characterized by spectroscopic and electrochemical methods and the inverted pyrrole structure was confirmed in the solid state for the first time by single crystal X-ray analysis.

Advanced materials for electrocatalytic oxygen reduction reaction (ORR) is crucial to a number of renewable energy applications. Herein, a hybrid of nitrogen-doped graphene (N-graphene) and NbOx (x = 2∼2.5) semiconductor nanosheets with sandwich-like structure has been designed and synthesized via a strategy of intercalation-in situ carbonization. The obtained multilayer hybrid material exhibits quite positive onset potential of ORR, good stability and excellent selectivity for ORR with high methanol tolerance. The enhanced performance could be attributed to the active oxygen vacancy from the partial reduction of Nb (V) during the carbonization process and the synergetic coupling effect resulting from the molecular level contact of N-graphene and NbOx (x = 2∼2.5) nanosheets, which makes it a promising substitute of platinum-based materials for renewable energy applications.

In this paper, a novel surfactant, N , N ′-diisopropoxypropyl- N ″, N ‴-oxydiethylenedicarbonyl bis (thiourea) (DiPOPECTU) was first introduced, and its adsorption thermodynamics and kinetics on chalcopyrite surfaces were investigated. DiPOPECTU exhibited superior hydrometallurgical performances for flotation recovery of chalcopyrite, and preferred attaching onto chalcopyrite surfaces at pH 5–10. The thermodynamic results demonstrated that the adsorption agreed well with Langmuir isotherm and its thermodynamic parameters were Δ G (298 K) = −23.48 kJ mol −1 , Δ S = −5.95 J mol −1 K −1 and Δ H = −25.28 kJ mol −1 , respectively. This inferred DiPOPECTU adsorption onto chalcopyrite was a spontaneously exothermic chemisorption process. The kinetic results showed that the adsorption process was well fitted by the pseudo-second-order equation. The adsorption rate constant was 0.14 × 10 5 m 2 mol −1 h −1 and the calculated equilibrium adsorption amount Q e (5.71 × 10 −5 mol m −2 ) was close to the experimental value Q e (5.41 × 10 −5 mol m −2 ). The results of diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy further indicated that DiPOPECTU might chemisorbed on chalcopyrite surfaces by formation of DiPOPECTU-copper complexes. The uniquely double chelate ring structures and steric orientation of DiPOPECTU on chalcopyrite surfaces would improve the hydrophobicity of chalcopyrite particles along with superior flotation recovery.

Caiying Zhu,1,* Jingjing Xiao,1,* Ming Tang,2 Hua Feng,1 Wulian Chen,3 Ming Du1 1Medical Center of Diagnosis and Treatment for Cervical Diseases, Obstetrics and Gynecology Hospital, Shanghai Medical College, Fudan University, Shanghai, 2Department of Otorhinolaryngology-Head and Neck Surgery, Ningbo Medical Center, Li Huli Hospital, Ningbo, 3State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai, China *These authors contributed equally to this work Abstract: The preparation of polymer therapeutics capable of controlled release of multiple chemotherapeutic drugs has remained a tough problem in synergistic combination cancer therapy. Herein, a novel dual-drug co-delivery system carrying doxorubicin (DOX) and platinum(IV) (Pt[IV]) was developed. An amphiphilic diblock copolymer, PCL-b-P(OEGMA-co-AzPMA), was synthesized and used as a nanoscale drug carrier in which DOX and Pt(IV) could be packaged together. The copolymers were shell cross-linked by Pt(IV) prodrug via a click reaction. Studies on the in vitro drug release and cellular uptake of the dual-drug co-delivery system showed that the micelles were effectively taken up by the cells and simultaneously released drugs in the cells. Futhermore, the co-delivery polymer nanoparticles caused much higher cell death in HeLa and A357 tumor cells than either the free drugs or single-drug-loaded micelles at the same dosage, exhibiting a synergistic combination of DOX and Pt(IV). The results obtained with the shell cross-linked micelles based on an anticancer drug used as a cross-linking linkage suggested a promising application of the micelles for multidrug delivery in combination cancer therapy. Keywords: dual-drug co-delivery system, amphiphilic diblock copolymer, shell cross-linked micelles, synergistic combination cancer therapy

The adsorption mechanism of N-butoxypropyl-N′-ethoxycarbonyl thiourea (BOPECTU) on chalcopyrite surfaces was investigated by thermodynamics, scanning electrochemical microscopy (SECM), and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. The thermodynamic results demonstrated that the adsorption agreed well with the Langmuir or Freundlich isotherm and the adsorption parameters of thermodynamics were ΔG (303 K) = −31.02 kJ mol−1, ΔS = 10.92 J mol−1 K−1 and ΔH = −27.71 kJ mol−1. It inferred the adsorption of BOPECTU on chalcopyrite was a spontaneously exothermic chemisorption process. The in situ SECM images indicated the adsorption of BOPECTU on chalcopyrite resulted in the decrease of the current response. DRIFT spectra exhibited that after BOPECTU treatment, the characteristic peaks of copper–BOPECTU complex appeared on chalcopyrite surfaces, while on pyrite or sphalerite surfaces, no new peaks appeared. UV–vis and FTIR spectra elucidated that BOPECTU showed more affinities to Cu2+ ions than to Zn2+, Fe3+ or Fe2+ ions, and might bond copper atoms with its sulfur and nitrogen atoms. The results of flotation and adsorption experiments further demonstrated BOPECTU owned stronger collecting ability to chalcopyrite than to sphalerite or pyrite.

Thiophosphorous compounds: diisobutyl dithiophosphate (DIBDTPA), diisobutyl dithiophosphinate (DIBDTPI), diisobutyl monothiophosphate (DIBMTPA) and diisobutyl monothiophosphinate (DIBMTPI) are widely used as flotation collectors and corrosion inhibitors, though the true nature of their bonding mechanisms to solid surfaces is still unclear. Using density functional theory (DFT) calculations, this study investigates the structure-reactivity relationship of these thiophosphorus molecules as flotation collectors with sulfide minerals. The results indicate that the O atom(s) bonded to the P atom in thiophosphorus molecules can significantly impact the chemical reactivity of the S atom(s) in the four reagents, and for DIBMTPA and DIBMTPI, they could even attend the chemical bond formation with metal atoms. The reactive power of the four compounds to mineral surfaces of Cu, Au, Ag and Pb sulfides is predicted to be DIBDTPI ≫ DIBMTPI ≥ DIBDTPA > DIBMTPA, and their flotation selectivity against pyrite and sphalerite is suggested as DIBDTPA

In this paper, 3,3′-diethyl-1,1′-oxydiethylenedicarbonyl bis(thiourea) (DEOECTU), was synthesized by phase transfer catalysis and then characterized by UV, elemental analysis, infrared spectra, mass spectrum, 1H NMR and TGA. DEOECTU properties, such as response to metal ions, adsorption on sulfide mineral surfaces, and hydrometallurgical performance as flotation collectors, were also investigated. The results indicated that DEOECTU reacted chemically with Cu2+ ions through its S and N atoms in the C(=S)–NH–C(=O) group to form a new chelate compound, but no reaction of DEOECTU with Zn2+, Pb2+, Fe3+ or Fe2+ ions was observed. The results of adsorption and flotation experiments demonstrated, that compared to pyrite, sphalerite and galena, DEOECTU exhibited a superior collecting power for chalcopyrite and might attach on chalcopyrite surface by chemisorption. The further theoretical analysis from Pearson’s HSAB view point briefly explained the experimental results of the selective response of DEOECTU to Cu2+ ions and chalcopyrite.

The preparation of a low-cost, high-efficient, and stable electrocatalyst as an alternative to platinum for the oxygen reduction reaction (ORR) is especially important to various energy storage components, such as fuel cells and metal–air batteries. Here, we report a new type of bonded double-doped graphene nanoribbon-based nonprecious metal catalysts in which Fe3C nanoparticles embedded in Fe-N-doped graphene nanoribbon (GNRs) frameworks through a simple pyrolysis. The as-obtained catalyst possesses several desirable merits for the ORR, such as diverse high-efficiency catalytic sites, a high specific surface area, an ideal hierarchical cellular structure, and a highly conductive N-doped GNR network. Accordingly, the prepared catalyst shows a superior ORR activity (an onset potential of 0.02 V and a half-wave potential of −0.148 V versus an Ag/AgCl electrode) in alkaline media, close to the commercial Pt/C catalyst. Moreover, it also displays good ORR behavior in an acidic solution.

To balance the anchoring sites and conductivity of the catalyst supports is a dilemma in electrocatalytic oxygen reduction reaction (ORR). Nitrogen-doped mesoporous graphene (N-MG) with large surface area, high porosity, and superior intrinsic conductivity has been developed to address this issue. Using N-MG as the backbone, a hybrid catalyst of Co3O4 nanocrystals embedded on N-MG (Co3O4/N-MG) was prepared for the electrocatalytic ORR in alkaline media. The Co3O4/N-MG showed high catalytic activity for the four-electron ORR, giving a more positive onset potential (0.93 V vs RHE) and a higher current density. The unique property of N-MG and the synergetic effect of Co3O4 and N-MG are prominent for ORR. With improved electrocatalytic activity and durability, the Co3O4/N-MG can be an efficient nonprecious metal catalyst and potentially used to substitute the platinum-based cathode catalysts in fuel cells and metal–air batteries.

In situ scanning electrochemical microscopy (SECM) was used to study N-isopropoxypropyl-N'-ethoxycarbonyl thiourea (iPOPECTU) adsorption on chalcopyrite. The in situ SECM images indicated a preferential adsorption of iPOPECTU on chalcopyrite surfaces, resulting in a decrease in the probing electrochemical current response. The surfaces after iPOPECTU adsorption were analyzed by time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS). ToF-SIMS results provided a strong evidence of iPOPECTU binding with copper only. XPS analysis showed the reduction of cupric to cuprous on chalcopyrite surfaces as a result of iPOPECTU adsorption. Our results shed light on adsorption mechanism of iPOPECTU on the surface of chalcopyrite samples.

Zirconium-pillared layered phosphates were prepared from α-zirconium phosphate and zirconium phosphate phenylphosphonate by colloid manipulation method. The pillared α-zirconium phosphates are less thermally stable than the pillared phosphate phenylphosphonates. The latter can hold their layered structure intact until 500°C, because the phenyl groups in the interlayer region inhibit the strong interaction between the oxide pillars and the sheets. Infrared and 31 P MAS-NMR spectroscopic studies show that P–O–Zr linkages are formed after calcination as a result of this strong interaction. The surface areas of the pillared materials may reach 153–183 m2/g, and their pore size distributions are narrow and centered ca. 2 nm. Surface acidity and basicity of the pillared materials were measured by infrared spectroscopy of pyridine adsorption and temperature-programmed desorption methods. They are weakly acidic, but almost non-basic. In comparison with ZrO2, they have more and stronger acid sites. The pillared materials, in particular the zirconium-pillared phosphate phenylphosphonate, are more catalytically active than ZrO2 for reactions such as dehydration of isopropanol, esterification of acetic acid with ethanol and reduction of benzaldehyde.

Palladium nanoparticles (Pd NPs) were loaded in situ on novel mesoporous carbon nanospheres (MCNs), which possess high specific surface area and large pore volume. The resulting Pd/MCNs hybrid nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). By using Pd/MCNs as the catalyst matrices to modify the surface of glassy carbon electrode, a nonenzymatic sensor was developed for the determination of hydrogen peroxide (H 2 O 2 ). Cyclic voltammetry (CV) and amperometry (at an applied potential of −0.30 V versus SCE) were used to study and optimize the performance of the electrochemical sensor. It was demonstrated that the sensor not only exhibits good electrocatalytic activity toward the reduction of H 2 O 2 but also has high sensitivity (307.5 μA mM −1 cm −2 ), low detection limit of 1.0 μM, and wide linear response range from 7.5 μM to 10 mM. Moreover, the sensor shows excellent stability and anti-interference capability for the detection of H 2 O 2 .