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To facilitate the dilute electrochemical nitrate reduction reaction (NO3−RR), definite structure identification and clear mechanism exploration are essential and challenging for the development of efficient electrocatalysts. Herein, an ultralow-content of metal (M, including Fe, Co and Ni) was introduced into Cu (M–Cu) by in situ electrochemical reconstitution of the oxides for NO3−RR at dilute NO3− concentration (≤100 ppm NO3−–N). Electrochemical evaluation reveals that the introduction of low-content metal can simultaneously facilitate the activity and selectivity of NO3−RR. For example, the Fe–Cu exhibits a significant FE of 93.4% and yield rate of 323.1 mmol h−1 gcat−1 for NH4+ formation, superior to those for Cu. Theoretical and experimental results show that the introduction of Fe simultaneously optimizes the adsorption of *NO2 and *H, and thus facilitates the subsequent hydrogenation, beneficial for NO3−RR. This study provides a universal metal doping strategy for boosting NO3−RR by the adsorption-transfer mechanism of *H. [ABSTRACT FROM AUTHOR]

Unidirectional cascade electron transfer induced by multi‐junctions is essential for deep electronic state regulation of the catalytic active sites, while this advanced concept has rarely been investigated in the field of electrocatalysis. In the present work, a dual junction heterostructure (FePc/L‐R/CN) is designed by anchoring iron phthalocyanine (FePc)/MXene (L‐Ti3C2‐R, R═OH or F) heterojunction on g‐C3N4 nanosheet substrates for electrocatalysis. The unidirectional cascade electron transfer (g‐C3N4 → L‐Ti3C2‐R → FePc) induced by the dual junction of FePc/L‐Ti3C2‐R and L‐Ti3C2‐R/g‐C3N4 makes the Fe center electron‐rich and therefore facilitates the adsorption of O2 in the oxygen reduction reaction (ORR). Moreover, the electron transfer between FePc and MXene is facilitated by the axial Fe─O coordination interaction of Fe with the OH in alkalized MXene nanosheets (L‐Ti3C2‐OH). As a result, FePc/L‐OH/CN exhibits an impressive ORR activity with a half‐wave potential (E1/2) of 0.92 V, which is superior over the catalysts with a single junction and the state‐of‐the‐art Pt/C (E1/2 = 0.85 V). This work provides a broad idea for deep regulation of electronic state by the unidirectional cascade multi‐step charge transfer and can be extended to other proton‐coupled electron transfer processes. [ABSTRACT FROM AUTHOR]

Herein, we report a facile strategy for constructing hybrid coordination configurations by combining functionalized graphene quantum dots (GQDs) with CoPc (CoPc/R-GQDs, with R being –NH2 or –OH) for electrochemical CO2 reduction. Benefiting from the high density of functional groups that can be provided by GQDs and the strong electron-donating property of –NH2, the examined CoPc/NH2-GQDs achieved a 100% faradaic efficiency for CO formation (FECO) at −0.8 to −0.9 V vs. RHE, and high FECO (over 90%) over a wide potential range of 500 mV. This work has presented a novel approach for catalyst design, specifically involving molecular engineering of quantum dots, which can also be applied to other essential electrochemical reactions. [ABSTRACT FROM AUTHOR]

Electrochemically converting NO3− into NH3 offers a promising route for water treatment. Nevertheless, electroreduction of dilute NO3− is still suffering from low activity and/or selectivity. Herein, B as a modifier was introduced to tune electronic states of Cu and further regulate the performance of electrochemical NO3− reduction reaction (NO3RR) with dilute NO3− concentration (≤100 ppm NO3−−N). Notably, a linear relationship was established by plotting NH3 yield vs. the oxidation state of Cu, indicating that the increase of Cu+ content leads to an enhanced NO3−‐to‐NH3 conversion activity. Under a low NO3−−N concentration of 100 ppm, the optimal Cu(B) catalyst displays a 100 % NO3−‐to‐NH3 conversion at −0.55 to −0.6 V vs. RHE, and a record‐high NH3 yield of 309 mmol h−1 gcat−1, which is more than 25 times compared with the pristine Cu nanoparticles (12 mmol h−1 gcat−1). This research provides an effective method for conversion of dilute NO3− to NH3, which has certain guiding significance for the efficient and green conversion of wastewater in the future. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of NO3− to NH3 production is of great environmental significance for water pollution treatment and can artificially close the nitrogen cycle. However, direct nine protons and eight electrons transfer lead to low Faraday efficiency (FE) and yield. Herein, the single copper site immobilized on N,P co‐doped carbon substrates (Cu−N4/P) was prepared for efficient NO3−‐to‐NH3 conversion. Benefiting from the electronic redistribution of the Cu site induced by the introduction of the less electronegative element P, the Cu−N4/P catalyst exhibited a high Faraday efficiency of FE (95.89 %) for NH3 product formation at a potential of −0.6 V vs. RHE and 100 % conversion of NO3−−N was achieved after 5 hours of electrolysis. Density functional theory (DFT) explains the effective operation mechanism that P doping can promote the spontaneous hydrogenation of *NO to form *NOH, thus promoting the formation of NH3 from NO3− reduction reaction. The heteroatom doping strategy mentioned proposes a new approach for promoting NO3−‐to‐NH3 conversion at atomic level catalytic sites. [ABSTRACT FROM AUTHOR]

The precise coordination environment manipulation and interfacial electron redistribution are significant strategies for the modulation of electronic configuration and intermediates adsorption behaviors, while the complex synergistic effect is yet to materialize due to the lack of catalyst platform. Herein, an atomic‐scale catalyst platform containing single Cu site with tunable coordination environment (Cu‐N4 or Cu‐S1N3) and easy decoration of Cu cluster (Cux) for electrochemical O2 reduction reaction (ORR) is reported. Theoretical analysis shows that the charge redistribution and up‐shifting d‐band center of single Cu site induced by the asymmetrical coordination environment and Cux effectively strength *OOH adsorption. The modulation in intermediates adsorption enables Cu‐S1N3/Cux a superior ORR performance compared with the samples without S atom and/or Cux. Moreover, the adsorption behavior of *OOH and d‐band center of single Cu site tuned by coordination environment and interfacial interactions are correlated linearly with catalytic potential, e.g., half‐wave potential and reaction kinetic, e.g., Tafel slope for ORR, indicating the high applicability of the intermediate adsorption strength and d‐band center as the indicators for catalytic performance. This study provides a comprehensive modulation strategy for electron configuration and intermediates adsorption behaviors, and can be extended to facilitate other proton‐coupled electron transfer reactions. [ABSTRACT FROM AUTHOR]

Bi‐based materials quickly rise as promising candidates for electrochemical CO2‐to‐formate conversion. However, most of them only display a narrow potential range for the desired formate selectivity. Herein, we designed an oxygen‐vacancy‐rich ultrasmall bismuth subcarbonate supported on reduced graphene oxide composite (Vo‐BOC/G) for electrochemical CO2‐to‐formate conversion. The Vo‐BOC/G exhibits an outstanding formate selectivity up to 100 % at −1.2 V vs. RHE and an impressive partial current density of 38 mA cm−2 in 0.1 M KHCO3. More importantly, the considerable formate selectivity (>80 %) was obtained over an impressively wide potential range of 600 mV, superior over most of reported Bi‐based electrocatalysts under the same conditions. Theoretical results show the abundant Vo defects significantly lower energy barrier for *CO2 formation, resulting in high formate selectivity over a wider potential window. This work may pave the way for Bi‐based materials application in different renewable energy‐conversion devices. [ABSTRACT FROM AUTHOR]

Carbon‐based single‐atom catalysts (SACs) with well‐defined and homogeneously dispersed metal−N4 moieties provide a great opportunity for CO2 reduction. However, controlling the binding strength of various reactive intermediates on catalyst surface is necessary to enhance the selectivity to a desired product, and it is still a challenge. In this work, the authors prepared Sn SACs consisting of atomically dispersed SnN3O1 active sites supported on N‐rich carbon matrix (Sn‐NOC) for efficient electrochemical CO2 reduction. Contrary to the classic Sn‐N4 configuration which gives HCOOH and H2 as the predominant products, Sn‐NOC with asymmetric atomic interface of SnN3O1 gives CO as the exclusive product. Experimental results and density functional theory calculations show that the atomic arrangement of SnN3O1 reduces the activation energy for *COO and *COOH formation, while increasing energy barrier for HCOO* formation significantly, thereby facilitating CO2‐to‐CO conversion and suppressing HCOOH production. This work provides a new way for enhancing the selectivity to a specific product by controlling individually the binding strength of each reactive intermediate on catalyst surface. [ABSTRACT FROM AUTHOR]

We developed a tandem electrocatalyst for CO2‐to‐CO conversion comprising the single Cu site co‐coordinated with N and S anchored carbon matrix (Cu‐S1N3) and atomically dispersed Cu clusters (Cux), denoted as Cu‐S1N3/Cux. The as‐prepared Cu‐S1N3/Cux composite presents a 100 % Faradaic efficiency towards CO generation (FECO) at −0.65 V vs. RHE and high FECO over 90 % from −0.55 to −0.75 V, outperforming the analogues with Cu‐N4 (FECO only 54 % at −0.7 V) and Cu‐S1N3 (FECO 70 % at −0.7 V) configurations. The unsymmetrical Cu‐S1N3 atomic interface in the carbon basal plane possesses an optimized binding energy for the key intermediate *COOH compared with Cu‐N4 site. At the same time, the adjacent Cux effectively promotes the protonation of *CO2− by accelerating water dissociation and offering *H to the Cu‐S1N3 active sites. This work provides a tandem strategy for facilitating proton‐coupled electron transfer over the atomic‐level catalytic sites. [ABSTRACT FROM AUTHOR]

Fly ash cenospheres have lots of applications in many industrial fields because of their good physicochemical properties. The formation stage, physicochemical properties, mineral phase composition and separation method of fly ash ashcenospheres are introduced. The applications of fly ash cenospheres as rubber and plastic filler, thermal insulation refractory, building material, composite foam, environmental functional material and wave absorbing material are reviewed. Some problems of low added value, low utilization rate and slow industrialization process in the application of fly ash ashcenospheres are analyzed. The future development direction is pointed out: the products should be developed at different levels according to the physicochemical characteristics of fly ash cenospheres in the direction of graded utilization and increasing product added value. The functional products of fly ash cenospheres in metal matrix composites, soil modifiers, coatings, ceramics and other aspects should be actively developed in order to widen the application fields. [ABSTRACT FROM AUTHOR]

In this study, a polyphosphate superplasticizer (PPE) used in sulphoaluminate cement was synthesized by using un-saturated phosphate ester as monomer. The effects of molecular structures of polyphosphate superplasticizer on the fluidity of sulphoaluminate cement paste were investigated. When n (HPEG) :n (MOEP) :n (TGA) :n (APS) was 1:4:0.2:0.1, the effect of PPE on the fluidity and fluidity retention of sulphoaluminate cement is better compared to ordinary polycarboxylate superplasticizer (PCE). The mechanism of polyphosphate superplasticizer was probed in detail by X-ray photoelectron spectroscopy (XPS). The results showed that after adding 1% polyphosphate superplasticizer, the peaks of Ca2p and Al2p of sulphoaluminate cement shifted 0.173 eV and 0.175 eV respectively, which were greater than those of ordinary polycarboxylate superplasticizer. Accordingly, this new type of polyphosphate superplasticizer synthesized by us can play its role in dispersing sulphoaluminate cement particles via strong chemisorption on their surfaces. [ABSTRACT FROM AUTHOR]

In this paper, industrial waste residue, mineral material and phosphate material are utilized as basic materials to gradually conduct a series of experiments, including experiment of single heavy metal stabilization (experiment I), experiment of compound heavy metals stabilization (experiment II) and verification research for stabilization of heavy metals in contaminated soils (experiment III). In experiment I, industrial waste residue possesses highest removal percentage of heavy metals, removal percentages of Pb, Zn, and Cd are all above 93%. After reaction between industrial waste residue and heavy metal solution, all pH value of the supernatant increase significantly, with an average increase of about 5. In experiment II, compound curing agent can achieve the simultaneous removal of three kinds of heavy metals. Removal percentages of Pb, Zn and Cd are 88.29%-99.95%, 40.73%-99.46% and 14.80%-98.35%, respectively. After reaction between compound curing agent and heavy metals solution, except for S13-S16 group, pH value of the supernatant slightly increases. Removal percentages of heavy metals, categories of minerals in the precipitate and intensity of mineral diffraction peaks vary with composition of compound curing agent. Cd2+ tends to form phosphate precipitate with PO43- , and the reaction between compound curing agent and heavy metals will generate a series of precipitates that are hardly soluble or slightly soluble in water in a neutral environment. Compared with the characteristic of precipitate generated in experiment I, no obvious lead nitrate hydroxide mineral phase generates during reaction of compound curing agent with the compound heavy metals. In experiment III, 1# curing agent has little influence on soil pH value, and the stabilization efficiency of heavy metals in contaminated soils using 2# compound curing agent is better than those using 1# compound curing agent. The test specimens with stabilization efficiency of heavy metals all higher than 85% are selected for BCR sequential extraction. Stabilization efficiency of the heavy metals in the test specimens is obvious, but the residual state ratio is relatively low. 1# compound curing agent is suitable for neutral and near-neutral soil; 2# compound curing agent is suitable for the contaminated soils under acidic to near-neutral conditions, and simultaneously adjusts soil pH and stabilizes heavy metals. [ABSTRACT FROM AUTHOR]

Prediction-for-perception theories suggest that the brain predicts incoming stimuli to facilitate their categorization. 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17 However, it remains unknown what the information contents of these predictions are, which hinders mechanistic explanations. This is because typical approaches cast predictions as an underconstrained contrast between two categories 18,19,20,21,22,23,24 —e.g., faces versus cars, which could lead to predictions of features specific to faces or cars, or features from both categories. Here, to pinpoint the information contents of predictions and thus their mechanistic processing in the brain, we identified the features that enable two different categorical perceptions of the same stimuli. We then trained multivariate classifiers to discern, from dynamic MEG brain responses, the features tied to each perception. With an auditory cueing design, we reveal where, when, and how the brain reactivates visual category features (versus the typical category contrast) before the stimulus is shown. We demonstrate that the predictions of category features have a more direct influence (bias) on subsequent decision behavior in participants than the typical category contrast. Specifically, these predictions are more precisely localized in the brain (lateralized), are more specifically driven by the auditory cues, and their reactivation strength before a stimulus presentation exerts a greater bias on how the individual participant later categorizes this stimulus. By characterizing the specific information contents that the brain predicts and then processes, our findings provide new insights into the brain's mechanisms of prediction for perception. • Investigated the visual content that the brain predicts for categorization • Showed that predicted content flows down from the ventral to the occipital cortex • Showed that content lateralizes in the occipital cortex before stimulus is shown • Demonstrated that per-trial strength of predicted content biases subsequent behavior Yan et al. reveal the visual contents that the brain predicts before the stimulus is shown. They show that these contents flow down from ventral to occipital cortex, where they are lateralized. Critically, strength of predicted content in the brain biases subsequent perceptual categorization behavior when the stimulus is shown. [ABSTRACT FROM AUTHOR]

Social class is a powerful hierarchy that determines many privileges and disadvantages. People form impressions of others' social class (like other important social attributes) from facial appearance, and these impressions correlate with stereotype judgments. However, what drives these related subjective judgments remains unknown. That is, what makes someone look like they are of higher or lower social class standing (e.g., rich or poor), and how does this relate to harmful or advantageous stereotypes? We addressed these questions using a perception-based data-driven method to model the specific threedimensional facial features that drive social class judgments and compared them to those of stereotype-related judgments (competence, warmth, dominance, and trustworthiness), based on White Western culture participants and face stimuli. Using a complementary data-reduction analysis and machine learning approach, we show that social class judgments are driven by a unique constellation of facial features that reflect multiple embedded stereotypes: poor-looking (vs. rich-looking) faces are wider, shorter, and flatter with downturned mouths and darker, cooler complexions, mirroring features of incompetent, cold, and untrustworthy-looking (vs. competent, warm, and trustworthy-looking) faces. Our results reveal the specific facial features that underlie the connection between impressions of social class and stereotype-related social traits, with implications for central social perception theories, including understanding the causal links between stereotype knowledge and social class judgments. We anticipate that our results will inform future interventions designed to interrupt biased perception and social inequalities. [ABSTRACT FROM AUTHOR]

Communication involves successfully deriving a speaker's meaning beyond the literal expression. Using fMRI, it was investigated how the listener's brain realizes distinctions between enrichment-based meanings and literal semantic meanings. The neural patterns of the Mandarin scalar quantifier you-de (similar to some in English) which implies the meanings not all and not most via scalar enrichment, with the specific quantifier shao-shu-de (similar to less than half in English) which lexico-semantically encodes the meanings not all and not most, were compared. Listeners heard sentences using either quantifier, paired with pictures in which either less than half, more than half, or all of the people depicted in the picture were doing the described activity; thus, the conditions included both implicature-based and semantics-based picture-sentence mismatches. Imaging results showed bilateral ventral IFG was activated for both kinds of mismatch, whereas basal ganglia and left dorsal IFG were activated uniquely for implicature-based mismatch. These findings suggest that resolving conflicts involving inferential aspects of meaning employs different neural mechanisms than the processing based on literal semantic meaning, and that the dorsal prefrontal/basal ganglia pathway makes a contribution to implicature-based interpretation. Furthermore, within the implicature-based conditions, different neural generators were implicated in the processing of strong implicature mismatch ( you-de in the context of a picture in which 'all' would have been true) and weak implicature mismatch ( you-de in the context of a picture in which 'most' would have been true), which may have important implications for theories of pragmatic comprehension. Hum Brain Mapp 38:3848-3864, 2017. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Carbide slag produced from chlor-alkali industry contains high amounts of calcium compounds and can potentially be used as raw material for cement production; however, it contains large amounts of chlorine so it is essential to evaluate the emissions of chlorinated organic pollutants, including polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs). A field study of the emission profiles of these pollutants in a cement plant using such slag was performed. The average concentrations of PCDD/Fs, PCBs, and PCNs in stack gases collected at the kiln back end were 6.31, 1.07, and 31.89 pg TEQ m −3 , respectively. PCDFs dominated over PCDDs in particulate samples. Di- to pentachlorinated biphenyls were dominant homologs in the particulate samples. MonoCBs were the dominant homolog in stack gases from the kiln back end, and homolog concentrations decreased with increasing chlorine numbers. Mono- and diCNs accounted for 48–98% of PCNs. The estimated toxic equivalents of stack gas emissions of PCNs, classified as new persistent organic pollutants under Stockholm Convention, were unexpectedly higher than those of PCDD/Fs and PCBs. A mass balance indicated that all of the toxic equivalents were reduced by this cement kiln system. The highest 2,3,7,8-PCDD/F output is with clinker. [ABSTRACT FROM AUTHOR]

Co-incineration of sewage sludge in cement kilns can be used for its disposal. In the present study, samples were collected from three cement production runs where sewage sludge and other wastes (e.g. municipal solid waste, waste acid and wet sewage sludge) were co-processed. The samples were analyzed for polychlorinated biphenyls (PCBs). The dioxin-like (dl)-PCB concentrations in the stack gases from run 1, 2, and 3 were 344.6, 548.7, and 104.3 pg m −3 , respectively. The toxic equivalency (TEQs) values for runs 1, 2, and 3 were 5.6, 8.9, and 0.7 pg TEQ Nm −3 , respectively. Calculation of net emissions for the three runs indicated that the co-incineration of other waste in addition to sewage sludge in cement kilns would not increase emission of the dl-PCBs. PCB concentrations in samples from the suspension boiler and humidifier tower, kiln-end bag filter, and cyclone preheater were much higher than those in samples from the kiln head area, indicating that these stages will be important for controlling PCB formation. Chlorinated biphenyl (CB)-77, CB-105 and CB-118 were the major dl-PCB congeners, CB-52, CB-101 were the major indicator PCB congeners, and tetra-CB to hexa-CB were the major homologues for the total input or output materials. [ABSTRACT FROM AUTHOR]

A field study and theoretical calculations on the profile and formation mechanism of polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/Fs) from two cement kilns co-incinerating municipal solid waste and sewage sludge were performed, and the PCDFs were mainly focused. The back-end areas of the cement kilns were identified to be the major sites of PCDD/F formation according to their distributions in particulate samples from different process stages. The proportions of tetra- to hexa-chlorinated dibenzofurans (∑Cl 4–6 CDFs) at the kiln back-end areas were in the range of 50–80% of the total PCDD/Fs in mass concentrations and 62–87% in toxic equivalent concentrations. These results indicated that ∑Cl 4–6 CDFs are the dominant homologs that should be the focus for reducing PCDD/F emissions in cement kilns that co-incinerate municipal solid waste and sewage sludge. It is speculated that the low contents of oxygen and copper compounds, as well as the alkaline conditions, may contribute to the dominance of ∑Cl 4–6 CDFs in the PCDD/Fs formed. Chlorination was assumed to be the mechanism of formation of PCDFs. The results from model predictions and thermodynamic calculations used to test this assumption were consistent with the PCDF profiles observed from the field study. [ABSTRACT FROM AUTHOR]

Co-processing municipal solid waste incinerator (MSWI) fly ash in cement kilns is challenging because the unintentional production of persistent organic pollutants (POPs) during the process is not well understood. The distributions, profiles and formation mechanisms of polychlorinated naphthalenes (PCNs) as new POPs covered under Stockholm Convention in two cement kilns co-processing MSWI fly ash were studied. The average concentrations of PCNs in stack gas samples were 710 ng m −3 . The PCN concentration in particle samples collected from different process stages in the cement kilns ranged from 1.1 to 84.7 ng g −1 . Three process sites including suspension pre-heater boiler, humidifier tower, and the kiln back-end bag filter were identified to be the major formation sites of PCNs in cement kilns co-processing MSWI fly ash. The PCN distribution patterns were similar to that of polychlorinated dibenzo- p -dioxin and dibenzofuran (PCDD/Fs), which indicates the possibility for simultaneous control of PCNs and PCDD/Fs in cement kilns co-processing fly ash. Chlorination was suggested to be an important formation mechanism of PCNs, and chlorination pathways of PCN congeners are proposed based on the congener profiles. Thermodynamic calculations, including relative thermal energies (Δ E ) and standard free energy of formation (Δ G ), and the charge densities of the carbon atoms in PCN supported the proposed chlorination mechanisms for PCN formation. The results presented in this study might provide helpful information for developing techniques and strategies to control PCN emissions during cement kilns co-processing MSWI fly ash. [ABSTRACT FROM AUTHOR]

Electrochemical conversion of NO3− to NH3 production is of great environmental significance for water pollution treatment and can artificially close the nitrogen cycle. However, direct nine protons and eight electrons transfer lead to low Faraday efficiency (FE) and yield. Herein, the single copper site immobilized on N,P co‐doped carbon substrates (Cu−N4/P) was prepared for efficient NO3−‐to‐NH3 conversion. Benefiting from the electronic redistribution of the Cu site induced by the introduction of the less electronegative element P, the Cu−N4/P catalyst exhibited a high Faraday efficiency of FE (95.89 %) for NH3 product formation at a potential of −0.6 V vs. RHE and 100 % conversion of NO3−−N was achieved after 5 hours of electrolysis. Density functional theory (DFT) explains the effective operation mechanism that P doping can promote the spontaneous hydrogenation of *NO to form *NOH, thus promoting the formation of NH3 from NO3− reduction reaction. The heteroatom doping strategy mentioned proposes a new approach for promoting NO3−‐to‐NH3 conversion at atomic level catalytic sites. [ABSTRACT FROM AUTHOR]