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Tuning the local reaction environment is an important and challenging issue for determining electrochemical performances. Herein, we propose a strategy of intentionally engineering the local reaction environment to yield highly active catalysts. Taking Ptδ− nanoparticles supported on oxygen vacancy enriched MgO nanosheets as a prototypical example, we have successfully created a local acid-like environment in the alkaline medium and achieve excellent hydrogen evolution reaction performances. The local acid-like environment is evidenced by operando Raman, synchrotron radiation infrared and X-ray absorption spectroscopy that observes a key H3O+ intermediate emergence on the surface of MgO and accumulation around Ptδ− sites during electrocatalysis. Further analysis confirms that the critical factors of the forming the local acid-like environment include: the oxygen vacancy enriched MgO facilitates H2O dissociation to generate H3O+ species; the F centers of MgO transfers its unpaired electrons to Pt, leading to the formation of electron-enriched Ptδ− species; positively charged H3O+ migrates to negatively charged Ptδ− and accumulates around Ptδ− nanoparticles due to the electrostatic attraction, thus creating a local acidic environment in the alkaline medium. While catalysts have intrinsic activities toward reactions, such performances often require further optimization. Here, authors engineer an acid-like environment in alkaline media by fine-tuning the reaction environment of platinum nanoparticles on oxide nanosheets for H2 evolution electrocatalysis. [ABSTRACT FROM AUTHOR]

In this paper, an ultrasensitive photoelectrochemical aptasensor based on amplified signal strategy and competitive mechanism for ochratoxin A (OTA) detection was developed. The prepared photoactive composite material (BiFeO 3 /Bi 2 S 3) possessed excellent separation ability of photogenerated electron-hole pair and effectively inhibited the recombination of hole and pair, resulting in significantly enhanced photocurrent intensity. The amplified signal strategy was achieved by adding methylene blue (MB), which facilitated electron transfer and improved the photoelectric conversion efficiency. In the presence of OTA, the aptamer can be recognized and captured, the complementary DNA (cDNA) and MB were released from the aptasensor electrode, a decreased photocurrent signal appeared, thus achieving quantitative detection for OTA. Under optimal conditions, the aptasensor exhibited a wide linear relationship range from 10−5 to 10−13 g/mL and a low detection limit of 0.0135 fg/mL (3σ/S). Simultaneously, the proposed photoelectrochemical aptasensor also showed excellent accuracy, stability, precision and selectivity. Schematic showing the steps involved in fabrication of the photoelectrochemical biosensor. [Display omitted] • The signal amplified photoelectrochemical aptasensor was established for the detection of ochratoxin A (OTA). • The photocurrent of composite material was 1.5 and 160 fold of pure Bi 2 S 3 and BiFeO 3 respectively. • Methylene blue (MB) was used as sensitizer to amplify the detection signal. • The proposed photoelectrochemical aptasensor presented wide detection range and ultra-low detection limit for OTA. [ABSTRACT FROM AUTHOR]

A simple one-pot method was developed to prepare PtNi alloy nanoparticles, which can be self-decorated on multiwalled carbon nanotubes in [BMIm][BF] ionic liquid. The nanohybrids are targeting stable nanocatalysts for fuel cell applications. The sizes of the supported PtNi nanoparticles are uniform and as small as 1-2 nm. Pt-to-Ni ratio was controllable by simply selecting a PtNi alloy target. The alloy nanoparticles with Pt-to-Ni ratio of 1:1 show high catalytic activity and stability for methanol electro-oxidation. The performance is much higher compared with those of both Pt-only nanoparticles and commercial Pt/C catalyst. The electronic structure characterization on the PtNi nanoparticles demonstrates that the electrons are transferred from Ni to Pt, which can suppress the CO poisoning effect. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: A [4Fe–4S]1+ cluster-containing protein activates 2-hydroxyisocaproyl-CoA dehydratase by an ATP-driven electron transfer. The activator has been proposed to change its conformation by MgATP similarly to nitrogenase Fe-protein. Iron chelation by bathophenanthroline removed the reduced [4Fe–4S]1+ cluster from the activator in an ATP-dependent manner (rate, v =0.128±0.004min−1; K m =21±1μM); with ADP no chelation was observed (v <0.001min−1). Chelation of the oxidised [4Fe–4S]2+ cluster occurred faster with ADP (v =0.34±0.05min−1) than with ATP (v =0.132±0.005min−1). The data indicate that reduction of the activator and binding of ATP induce conformational changes necessary to transfer the electron to the dehydratase. Interaction of both proteins promotes ATP hydrolysis (K m =0.5±0.1μM). [Copyright &y& Elsevier]

[Display omitted] • The correlation between the power generation and pollutant degradation was determined. • Activated carbon (AC) improves the pollutant transfer from liquid phase to biofilm. • Modified ruthenium (Ru) accelerates the electron transfer from biofilm to anode. • The Ru-AC bioanode enhances chlorobenzenes removal and power generation. • Ru and AC together promote the conversion of chlorophenols to organic acids. Microbial fuel cell (MFC) is a promising device for water decontamination and energy generation. However, the correlation between power generation and pollutant degradation has not been clarified. Herein, a ruthenium–activated carbon (Ru–AC) bioanode was constructed for chlorobenzenes (CBs) treatment. The pollutant tolerance was improved by Ru–AC anode, and the minimum removal efficiencies of CB and ortho -dichlorobenzene (o -DCB) reached 75.1 % and 69.3 %, respectively, which were considerably higher than those of other MFCs (16.3 %–39.7 %). Correspondingly, the maximum output voltage reached 360.7 mV for the Ru–AC anode, whereas the values obtained from others reached 45.2–149.6 mV. Interaction models were introduced to quantify the relationship between power generation and pollutant degradation. The conversion of highly toxic chlorophenols to organic acids could be accelerated by boosting the mass and electron transfer, thereby simultaneously enhancing CBs removal and power generation. This work provided important insights into pollutant-powered MFC development. [ABSTRACT FROM AUTHOR]

The practical application of a photocatalytic fuel cell (PFC) is usually limited by its long pollutant degradation period. Here, two strategies were adopted to improve the PFC performance. On one hand, a ternary Z-scheme heterojunction photocatalyst (Bi 2 O 4 /Bi 2 WO 6 /C 3 N 4 qds) was used as the photoanode to promote the separation of photo-generated charge carriers, thereby improving the photocatalytic process. On the other hand, CuFe 2 O 4 was used as the photocathode to activate persulfate (PS) to further enhance pollutant degradation and electricity generation. The results indicated that, under visible light irradiation (45 min), the degradation efficiency of tetracycline by the coupling system of Bi 2 O 4 /Bi 2 WO 6 /C 3 N 4 qds-CuFe 2 O 4 + PS (PFCps) reached to 94.5%. The corresponding first-order kinetic constant was 8.13, 3.40, 3.34, and 1.89 times that of PS, Bi 2 O 4 /Bi 2 WO 6 /C 3 N 4 qds + PS, CuFe 2 O 4 + PS, and Bi 2 O 4 /Bi 2 WO 6 /C 3 N 4 qds-CuFe 2 O 4 , respectively. The highest maximum power density of the PFCps system was 37.0 μW·cm−2, which was 1.89 times that of the PFC of Bi 2 O 4 /Bi 2 WO 6 /C 3 N 4 qds-CuFe 2 O 4. The reactive species capturing experiments verified that ·OH, ·O 2 -, h +, and ·SO 4 - had positive effects on the tetracycline degradation. In addition, the mechanism involved in the PFCps system was proposed. This work provided a novel idea for the development of coupling technologies to treat antibiotic wastewater. [Display omitted] • A ternary Z-scheme heterojunction was prepared by combining Bi 2 O 4 , Bi 2 WO 6 and C 3 N 4 qds • The Z-scheme photocatalyst promoted electron transfer from photoanode to photocathode • PS activation was facilitated in this Z-scheme PFC with CuFe 2 O 4 as photocathode • PFC+PS system simultaneously enhanced TC degradation and electricity generation • ·OH, ·O 2 -, h +, and ·SO 4 - had positive effects on TC degradation in the PFC+PS system [ABSTRACT FROM AUTHOR]

In this study, to overcome the problems of photo corrosion and structural instability, an attempt was made to construct a semiconductor heterojunction with MOF that can resist photo corrosion and reduction to adjust the electron (e−) transport path. The crystal stability and photo corrosion resistance are improved by creating Z-type heterojunctions to change the electron transfer path of Ag photocatalysts. MOFs have unique optical, electrical, and catalytic properties and thus play a key role in optimizing electron transfer pathways. Even if a semiconductor-catalyst heterojunction is constructed, migration-matched catalysts induce a cascade of crystal reduction and photo corrosion in a built-in electric field. At this time, PENS provides an electron acceptor platform, which can temporarily store photoelectrons, prevent the decrease of photoelectrons to the crystal, and improve electron transfer efficiency. The degradation of antibiotics and dyes assessed the resulting impact on photocatalytic efficiency under simulated sunlight, and photocatalytic activity was measured with an eye toward real outdoor applications. Due to the synergistic effect of the double self-cleaning structure, the ultrafiltration membrane exhibits superhydrophilic/underwater superoleophobic properties. It shows excellent separation efficiency and recyclability in the separation of oil-in-water emulsion experiments. [Display omitted] • Z-scheme facilitates the separation and transfer of charge carriers. • Flexibility, temperature resistance and acid and alkali resistance were achieved. • Membrane reactor exhibits efficient photocatalytic mineralization of antibiotics. • Superhydrophilic/underwater superoleophobic to achieve efficient oil-water separation. • Very robust performance over re-use cycles (×8 times) was achieved. This study fabricated PENS/TA/ZIF-67@Ag 2 S (PZA), a double self-cleaning network antifouling polymer membrane reactor, by the non-solvent-induced phase separation (NIPS) method. Due to the synergistic effect of the double self-cleaning structure, it showed an excellent separation efficiency of 99.65% and a high flux of 1198.011 L·m−2·h−1 in the separation of oil-in-water emulsion experiments. After eight cycles, Oil-water separation efficiency remains >99% recyclable. The Z-type heterogeneous conjunctival reactor we constructed has a high-efficiency degradation rate of 99.94% and a mineralization rate of 80.315% for sulfamethoxazole (SMX) within 120 min. From the results of mechanical properties, TGA and DSC, it can be seen that PZA has good strength, toughness and high temperature resistance. According to the experimental analysis of active substances, the active ingredients produced by PZA are •OH., h+, •O 2 –. Based on Density functional theory (DFT) calculations and intermediate analysis, sulfamethoxazole's active sites and degradation pathways (SMX) were explored. According to the Quantitative Structure-Activity Relationship (QSAR) of the Toxicity Estimation Software Tool (TEST), the toxicity of the intermediates produced during the degradation of SMX was predicted. This study provides a feasible strategy for fabricating Z-scheme metal-organic framework (MOF)-based polymer membrane reactors for efficient green antibiotic wastewater treatment and oil-water self-cleaning. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enhanced light absorption was obtained by modification of H 2 BDC with –NH 2. • Ce substitution increased electron transfer from photoexcited organic linkers to Zr-oxo clusters. • (Zr/Ce)U(NH 2)@CN Z-scheme heterojunction strengthened interfacial electrons transfer. • g-C 3 N 4 regulated the morphology and texture feature of (Zr/Ce)U(NH 2) matrix. Aiming at efficient tetracycline (TC) removal, a co-modified (Zr/Ce)U(NH 2) was elaborately designed and integrated with thin-layered g-C 3 N 4 , forming a novel (Zr/Ce)U(NH 2)@CN Z-scheme heterojunction. XRD, XPS, FTIR, ISI-XPS and other analysis cooperatively demonstrated that within this (Zr/Ce)U(NH 2)@CN composite organic linkers H 2 BDC was successfully modified by –NH 2 , metal Zr in Zr-oxo cluster was partially substituted by Ce, Z-scheme heterojunction was formed by the close interaction between MOFs and g-C 3 N 4 , as well as the excellent thermal stability and large specific surface area were achieved. Since g-C 3 N 4 could serve as carrier skeleton to improve the precursor dispersion, the (Zr/Ce)U(NH 2) with reduced particle size grew densely on it. DRS, PL and TRPL characterization proved more photogenerated carriers with prolonged lifetime were generated. As expected, (Zr/Ce)U(NH 2)@CN composite exhibited high TC degradation rate, whose kinetic constant was 23.73 times greater than that of UiO-66, and 5.89 folds larger than that of CN, respectively. This enhanced photocatalytic performance was ascribed to the effective electron transfer regulated by MOFs unit, where the Zr/Ce improved the electron transfer from photoexcited organic linkers to metal-oxo clusters, as well as the MOFs/g-C 3 N 4 Z-scheme heterojunction strengthened interfacial photogenerated carriers transfer. ·OH was the vital species responsible for TC removal using (Zr/Ce)U(NH 2)@CN. Furthermore, intermediate products and degradation pathways were proposed based on HPLC-MS. The toxicity estimation indicated the comprehensive toxicity of TC was significantly alleviated by (Zr/Ce)U(NH 2)@CN photocatalysis. [ABSTRACT FROM AUTHOR]

Two Keggin-type polyoxometalates [K6CoIIW12O40 (denoted as {CoIIW12}) and K5CoIIIW12O40 (denoted as {CoIIIW12})] were firstly employed as the redox couple in dye-sensitized solar cells. Photocurrent density-photovoltage curves, cyclic voltammetry curves, photocurrent action spectra and UV-vis spectra demonstrated that {CoIIW12} and {CoIIIW12} displayed weak absorption in the visible light region, potential matching with dye and TiO2 conducting band, and significant conversion efficiency. [ABSTRACT FROM AUTHOR]

[Display omitted] • Enhanced light absorption was obtained by integrating C 3 N 4 with Fe 2 O 3. • C 3 N 4 /Fe 2 O 3 heterojunction facilitated the separation of photogenerated carriers. • The applied bias extracted e- to external circuit and thus improved the quantum yield. • The synergy of photocatalysis and electrocatalysis was achieved using C 3 N 4 NSs/Fe 2 O 3 NRAs. • The photoelectrocatalysis using developed photoanode was caused by e-, ·OH and h+. The massive discharge of p-nitrophenol (PNP) has adversely affected ecosystem and human health. In this work, the g-C 3 N 4 nanosheets was integrated with α-Fe 2 O 3 nanorod arrays (C 3 N 4 NSs/Fe 2 O 3 NRAs) through simple in-situ hydrothermal and electrochemical deposition, and applied for the photoelectrocatalytic degradation of PNP. At the optimum experiment conditions at PNP initial concentration of 10 mg/L, pH value of 6.1, electrolyte concentration of 0.2 mol/L, and bias voltage of 1.5 V, the optimized photoanode displayed the highest PNP removal rate. This improvement was attributed to the synergistic effect between photocatalysis and electrocatalysis, a synergy factor of 1.6 was achieved during this C 3 N 4 NSs/Fe 2 O 3 NRAs photoelectrocatalytic system. The C 3 N 4 /Fe 2 O 3 heterojunction and bias voltage facilitated the generation, separation and transfer of electron/hole pairs. The electrolysis also provided rich active species, hydroxyl radicals, etc., which cooperated with the reactive oxygen species derived from enhanced photocatalysis to achieve rapid pollutants decomposition. Based on the intermediates detection and analysis, two PNP degradation pathways, namely direct oxidation and reduction–oxidation path, were proposed, that matched well the existence form and transformation rule of inorganic nitrogen. The radical capture experiments demonstrated that electrons, hydroxyl radicals and holes were the main species responsible for PNP photoelectrocatalytic removal. [ABSTRACT FROM AUTHOR]

[Display omitted] A self-standing NiFe-LDH@CoS x /NF electrocatalyst is developed by electrodepositing amorphous CoS x onto NiFe-LDH nanosheet arrays, which shows highly efficient performance towards overall water splitting. • A novel self-standing 3D NiFe-LDH@CoS x /NF bifunctional electrocatalyst is fabricated. • Integration of HER-active CoS x and OER-effective NiFe-LDH endows dual-function activity. • The NiFe-LDH@CoS x /NF assembly requires ultralow overpotentials for both HER and OER. • Interface interactions and synergistic effect favor the both HER and OER activity. Electrocatalytical water splitting to produce hydrogen energy is a promising green technology to solve energy crisis and environmental issues. The development of highly efficient and low-cost electrocatalysts is crucial for mass hydrogen production from water splitting. We newly assemble the self-standing 3D NiFe-LDH@CoS x /NF bifunctional electrocatalysts, via the electrodeposition of amorphous CoS x on two-dimensional (2D) NiFe-LDH nanosheets which are supported by porous nickel foam (NF). The integration of HER-active electrocatalyst of CoS x with outstanding OER catalyst of NiFe-LDH guarantees the bifunctional electrocatalytic activity. Furthermore, the formation of the constructed interfaces between amorphous CoS x and NiFe-LDH nanosheets synergistically favors the electron transfer. Therefore, this novel NiFe-LDH@CoS x /NF hierarchical assembly needs ultralow overpotentials of 136 mV (for HER) and 206 mV (for OER) to afford the 10 mA cm−2 current density in alkaline medium (1 M KOH). An electrolyzer based on the NiFe-LDH@CoS x /NF produces an extremely low cell voltage (1.537 V) and good durability. This study offers a promising strategy for facile fabrication of low-cost electrocatalysts which boost the electrocatalytic performance for overall water splitting. [ABSTRACT FROM AUTHOR]