FeCoNi molybdenum-based oxides for efficient electrocatalytic oxygen evolution reaction.

The search for highly efficient and inexpensive electrocatalysts is crucial to the advancement of environmentally friendly and sustainable energy sources. Here, adopting a one-step hydrothermal method, we have effectively fabricated a self-supported multi-metal molybdenum-based oxide (FeCoNi-MoO4) on nickel foam (NF). In addition to changing the catalyst's microstructure, the introducing of Fe and Co, enhanced its active center count, improved its electronic structure, and in turn reduced the difficulty for high-valence Ni and Fe species to form, which accelerates the oxygen evolution reaction (OER) kinetics by promoting the development of the actual active materials, NiOOH and FeOOH. FeCoNi-MoO4 has outstanding OER performance, requiring just 204 mV overpotentials at 10 mA cm-2 and 271 mV at 100 mA cm-2. Its exceptional OER kinetics at both low and high currents are indicated by a Tafel slope of 50.6 mV dec-1, which is attributed to the combined effect of its multi-metal composition and a higher number of active sites. Moreover, the FeCoNi-MoO4 electrode was operated continuously for over 48 h. Furthermore, the density functional theory (DFT) results demonstrated that the introducing of Fe and Co, which quickens the rate of electron transfer during the electrocatalytic process, improves the ability of oxygen intermediate species to adsorb, and ultimately lowers the overpotential, is responsible for the increased electrocatalytic activity of FeCoNi-MoO4. This work offers hope for further developments in the sector by proposing an efficient approach for creating multi-active electrocatalysts that are stable, economical, and efficient.

Constructing a 3D Bi2WO6/ZnIn2S4 direct Z-scheme heterostructure for improved photocatalytic CO2 reduction performance.

Developing efficient heterojunction photocatalysts with enhanced charge transfer and reduced recombination rates of photogenerated carriers is crucial for harnessing solar energy in the photocatalytic CO2 reduction into renewable fuels. This study employed electrostatic self-assembly techniques to construct a 3D Bi2WO6/ZnIn2S4 direct Z-scheme heterojunctions. The unique 3D structure provided abundant active sites and facilitated CO2 adsorption. Moreover, the optimized Bi2WO6/ZnIn2S4 composite demonstrated an impressive CH4 yield of 19.54 µmol g-1 under 4 h of simulated sunlight irradiation, which was about 8.73 and 16.30-fold higher than pure ZnIn2S4 and Bi2WO6. The observed enhancements in photocatalytic performance are attributed to forming a direct Z-scheme heterojunction, which effectively promotes charge transport and migration. This research introduces a novel strategy for constructing photocatalysts through the synergistic effect of morphological interface modifications.

Construction of Z scheme S-g-C3N4/Bi5O7I photocatalysts for enhanced photocatalytic removal of Hg0 and carrier separation.

Photocatalysis has demonstrated the potential to solve challenges in various practical application fields such as energy and environmental science due to its environmental friendliness. However, the photocatalytic activity is mainly affected by the weak absorption of visible light and the low separation efficiency of photogenerated carriers. Herein, an S-doped g-C3N4/Bi5O7I heterojunction was designed by the calcination method. It was found that S doping not only reduces the band gap of g-C3N4, which raises the optical absorption boundary of g-C3N4 from 465 nm to 550 nm. At the same time, the introduction of S elements leads to new doping energy levels, which can act as photogenerated electron trapping centers and thus inhibit the complexation of photogenerated carriers. Second, the construction of the heterojunction greatly facilitates the transport of carriers and the separation of electrons and holes driven by the built-in electric field. Finally, the abundant oxygen vacancies in the system result in defective energy levels that not only promote the activation of molecular oxygen, but also act as photogenerated electron traps, which further boost the separation of electron-hole pairs. Benefiting from the optimized performance, the photocatalytic reaction rates of S-doped g-C3N4/Bi5O7I are 5.2 and 2.1 times higher than those of g-C3N4 and Bi5O7I, respectively. This work provides a viable idea for the potential development of non-metal doping combined with heterojunction photocatalytic systems.

The preparation of slow-release fertilizers with biomass ash and water/waste acid solutions from desulfurization and denitrification of flue gas.

In this study, a method of preparing fertilizers with the fly ash from biomass power plants and the waste acid solution from flue gas desulfurization and denitrification was disclosed. In addition, the study also explored the effects of added fine particles, unburned biochar, and other commercial fertilizers on soil water retention and slow-release effect of fertilizers. The analysis was done by comparing the aggregation degrees of crystalline salt and the variations of the chemical bonds. The experimental results showed that the added fine particles could effectively increase the water absorption of fertilizers, which helped to improve soil water retention. Meanwhile, the fine particles could strengthen the special adsorption of basic compounds containing N, P, and other nutrients by biochar and enhance the slow-release effect of fertilizers. Although adding part commercial fertilizers weakened the water absorption of fertilizers slightly, it had only a relatively small effect on the aggregation of water-soluble crystalline salt on the surfaces of fine particles and biochar. Furthermore, the microwave was applied to promote the absorption of N by unburned biochar, during which only small amounts of volatile were released and lost. The experiments had confirmed that microwave irradiation could promote the agglomeration of biochar on crystalline salt effectively, thus enhancing the slow-release effect of crystalline salt in fertilizers. Finally, pot experiments demonstrated that the self-prepared fertilizer improved plant growth by its better water absorption and slow-release properties during the whole growth period, which had promising application potential as the slow-release fertilizer in the plant growth field.

First principles study on electronic properties and oxygen evolution mechanism of 2D bimetallic N-doped graphene.

Currently, the oxygen evolution reaction (OER) is constrained by complex four-electron transport, thus it is difficult to understand the catalytic mechanism. In this work, the electronic properties and catalytic performance of M1M2/NC (M = Mn, Fe, Co, Ni, Cu and Zn, random combination in pairs) is studied by density functional theory, the calculated results show that the overpotential of FeCu/NC is 0.88 V, which is used as the optimal catalyst to further study the OER reaction mechanism. Combined with the volcano map and the d-band center position, the low overpotential of FeCu/NC is because it has a more suitable position of d-band center -1.806 eV than other materials. Moreover, the calculation results show that the density of states (DOS) of iron-containing materials is stronger than that of other materials near the Fermi level, which can promote the catalytic reaction. In addition, O∗OH and O∗H, O∗H and O∗ linearly related theoretical equations are proposed, respectively. Furthermore, the analysis of the catalytic mechanism shows that the formation of the catalytic rate-determining step is affected by the movement of the d-band center, the distance of the transition state adsorption and the electric field.

Spherical-shaped CuS modified carbon nitride nanosheet for efficient capture of elemental mercury from flue gas at low temperature.

Mercury (Hg0) pollution poses a huge threat to human health and the environment due to its high toxicity, long persistence and bioaccumulation in the environment. Most of the traditional Hg0 adsorbents have a low reaction rate, high operating cost, especially poor resistance to SO2, which limited their practical application. In this work, nanosheet g-C3N4 was used as the support and modified by CuS to capture flue gas mercury. Take advantage of the large specific surface area of g-C3N4 to increase the BET of the composite and decrease the use of CuS. The effects of CuS loading, reaction temperature, and common components in the coal-fired flue gas on the mercury removal performance were studied respectively. The experimental outcomes showed that the 10CuS/g-C3N4 (10CuS/CN) reaches as high as almost 100% Hg0 removal efficiency under the temperature of 40-120 â„ƒ. Meanwhile the common components like SO2, NO, HCl and H2O have no obvious inhibition effects on Hg0 removal efficiency of the 10CuS/CN adsorbent. Sx2- and Cu2+ as the primary bonding sites shows a synergy effect on Hg0 removal. 10CuS/CN is a promising material for Hg0 removal under various flue gas conditions, which is expected to be a substitute for traditional adsorbents.

Study on arsenic, selenium, and lead produced in coal combustion: bibliometric method.

The literature on trace element pollutants (arsenic, selenium, lead) produced during coal burning from 2007 to 2020 was summarized by the bibliometric method, and the characteristics of published articles and research trends were analyzed. Taking 2007 as the starting point for statistics on articles in this research direction, there was a process of rapid growth in the total number of published articles by 2015, and it was increased over time. In the last 5 years of statistics, it is found that the number of articles published in China is the largest, accounting for almost half of the total. Most of the articles are published in the fields of energy, environmental protection, etc. Among them, the research on arsenic, selenium, and lead is mainly related to the use of adsorbents. At the same time, the effects of temperature, catalyst, material, and other conditions on the removal efficiency of arsenic, selenium, and lead in coal were considered. Application of photocatalysis, preparation of new adsorption materials, and mining of the properties of existing materials under different experimental conditions are a good development prospect.

Studies of Ozone-Sensitized Low- and High-Temperature Oxidations of Diethyl Carbonate.

Diethyl carbonate (DEC) oxidation with different levels of O3 addition was performed in an atmospheric laminar flow reactor from 400 to 850 K. Experimental results showed that, without O3 addition, the oxidation of DEC began from 650 K with no low-temperature reactivity, while with O3 addition the low-temperature chemistry of DEC was observed from 450 K. A DEC/O3 kinetic model was developed, and the model predictions agreed with the experimental data reasonably well with a slight overprediction of DEC oxidation between 550 and 750 K. The low-temperature chemistry of DEC with O3 addition was described in the reaction pathway of DEC. It was found that O3 assisted the low-temperature oxidation of DEC mainly through the production of the active O: atom instead of the direct reaction with the fuel molecule. The present work indicated that the Li-ion battery degradation at 400-500 K might result from the low-temperature chemistry of DEC with active oxygen supplies from the cathode metal oxide materials or from singlet O2 during the battery discharge process. This article used O3 to mimic the oxidizing environment in the Li-ion battery by providing active atomic oxygen. It provided insights into the chemically sensitized gas-phase low-temperature chemistry of DEC and explained the mechanism of battery degradation involving the low-temperature oxidation at the electrolyte solvent and the cathode interface from 400 to 500 K.

Self-grown oxygen vacancies-rich CeO2/BiOBr Z-scheme heterojunction decorated with rGO as charge transfer channel for enhanced photocatalytic oxidation of elemental mercury.

Oxygen vacancy-rich CeO2/BiOBr was prepared via solvothermal method combined with rGO to design a Z-scheme heterojunction, which was used for photocatalytic oxidation of gaseous elemental mercury. The Z-scheme heterojunction constructed by interface engineering significantly promotes charge carriers transfer at the interface. Moreover, the surface oxygen vacancies and Ce3+/Ce4+ redox centers tend to capture electrons to accelerate the Z-scheme path of charge transfer to maintain efficient redox performance and facilitate molecular oxygen activation to boost photocatalytic removal of Hg0. The collaboration of oxygen vacancies, Ce3+/Ce4+ and heterojunction enhances the photocatalytic oxidation activity, which achieves a removal efficiency of 76.53%, which is 1.29 times that of BiOBr and 1.91 times that of CeO2. The effect of actual flue gas components (SO2, NO and HCl) on the performance of photocatalytic Hg0 removal was further investigated. Combined with DFT theoretical calculations, the photocatalytic reaction mechanism of Z-scheme heterojunction with oxygen vacancies-rich was proposed. It provides a feasible strategy for the development of high-efficiency Z-scheme heterojunction photocatalytic system for environmental purification.

Influence of BiOIO3 morphology on the photocatalytic efficiency of Z-scheme BiOIO3/g-C3N4 heterojunctioned composite for Hg0 removal.

The morphology of catalyst is a very important factor influencing the photocatalytic activity of the catalyst. Owing to its scientific and technological importance, controllable preparation of photocatalysts with different morphologies has been studied. In this work, BiOIO3/g-C3N4 heterojunction composites are synthesized using hydrothermal method and the composites with different morphologies are fabricated by adjusting the amount of NaOH in precursor solutions to control the growth of BiOIO3 crystal plane. The physicochemical properties of BiOIO3/g-C3N4 heterojunction composites were investigated by XRD, XPS, FTIR, SEM, TEM, HRTEM, BET, UV-vis DRS and PL characterization. The effect of the BiOIO3 morphology on the photocatalytic efficiency of BiOIO3/g-C3N4 heterojunction composites was evaluated by photocatalytic removal of gas-phase Hg0 under visible light irradiation. When the morphology of BiOIO3 is regular square-like, BiOIO3/g-C3N4 has the optimal removal efficiency 92.6% of Hg0. Finally, electron-hole migration path and photocatalytic mechanism of catalysts are proposed.

Assessment of fine-scale parameterizations at low latitudes of the North Pacific.

Fine-scale parameterizations based on shear and stratification are widely used to study the intensity and spatial distribution of turbulent diapycnal mixing in the ocean. Two well-known fine-scale parameterizations, Gregg-Henyey-Polzin (GHP) parameterization and MacKinnon-Gregg (MG) parameterization, are assessed with the full-depth microstructure data obtained in the North Pacific. The GHP parameterization commonly used in the open ocean succeeds in reproducing the dissipation rates over smooth topography but fails to predict the turbulence over rough topography. Failure of GHP parameterization over rough topography is attributed to the deviation of internal wave spectrum from the Garrett-Munk (GM) spectrum. The internal wave field over rough topography is characterized by energetic intermediate-scale and small-scale internal waves that are not described well by the GM model. The MG parameterization that is widely used in coastal environments is found to be successful in reproducing the dissipation rates over both smooth and rough topographies. The efficacy of GHP and MG parameterizations in evaluating the dissipation rates has been assessed. The result indicates that MG parameterization predicts the magnitude and variability of the dissipation rates better than the GHP parameterization.

Adrenomedullin(27-52) inhibits vascular calcification in rats.

Adrenomedullin (ADM) has the vasodilatory properties and involves in the pathogenesis of vascular calcification. ADM could be degraded into more than six fragments in the body, including ADM(27-52), and we suppose the degrading fragments from ADM do the same bioactivities as derived peptides from pro-adrenomedullin. The present study carries forward by assessing the effects on vascular calcification of the systemic administration of ADM(27-52). The rat vascular calcific model was replicated with vitamin D3 and nicotine. ADM or/and ADM(27-52) were systemically administrated with mini-osmotic pump beginning at seventh day after the model replication for 25 days. Vascular calcific nodules histomorphometry, vascular calcium content, vascular calcium uptake, alkaline phosphatase activity, and osteopontin-mRNA quantification in aorta were assessed. ADM limited 40.2% vascular calcific nodules (P<0.01), did not effect on calcium content (P>0.05), reduced 44.4% calcium uptake (P<0.01), lowered 21.1% alkaline phosphatase activity (P<0.01), and regulated 40.9% downwards osteopontin-mRNA expression (P<0.01) in the aorta of rats with vascular calcification. ADM(27-52) receded 32.0% vascular calcific nodules (P<0.01), taken from 55.5% calcium content (P<0.01), did not affect calcium uptake (P>0.05), inhibited 22.5% alkaline phosphatase activity (P<0.01), and restrained 21.9% osteopontin-mRNA expression (P<0.01) in the aorta of rats with vascular calcification. Both of ADM and ADM(27-52) did interact on vascular calcification each other. ADM could partially antagonize the effects of ADM(27-52) in taking from calcium content (17.5%, P<0.01) and in receding vascular calcific nodules (18.6%, P<0.01). ADM could obviously enhance the action of ADM(27-52) in inhibiting alkaline phosphatase activity (14.4%, P<0.01) and in reducing calcium uptake (11.4%, P<0.01). ADM(27-52) could partially antagonize the effects of ADM on regulating downwards osteopontin-mRNA expression (17.0%, P<0.01). It is concluded that ADM(27-52) derived from ADM acts as an inhibitory agent on vascular calcification, with special mechanisms different from ADM derived from ADM progenitor molecule.

Effects of adrenomedullin on cell proliferation in rat adventitia induced by aldosterone.

OBJECTIVE: Aldosterone is involved in cardiovascular diseases such as hypertension and heart failure by inducing sodium retention and vascular remodeling, which is characterized by fibroblast proliferation and migration in adventitia. It is well known that aldosterone stimulates vascular smooth muscle cells and fibroblasts to produce and secrete adrenomedullin (ADM), a multiple functional peptide with an important cytoprotective effect against cardiovascular damage. We examined the effect of aldosterone on ADM production and secretion and its mRNA expression in rat aortic adventitia to study the paracrine/autocrine interaction between endogenous ADM and aldosterone. METHODS: ADM produced and secreted from adventitia stimulated by aldosterone in the absence or presence of spironolactone, RU486 or spironolactone together with RU486 were detected by radioimmunoassay, proliferation in adventitia cells was evaluated by the level of [H]-thymine incorporation, and preproADM gene expression was measured by semi-quantitative reverse transcriptase polymerase chain reaction. RESULTS: Adventitial ADM secretion and mRNA expression stimulated by aldosterone were concentration-dependent as was the inhibitive effect of ADM on aldosterone-induced proliferation. The induction of aldosterone in ADM secretion was mediated by mineralocorticoid receptor. Antagonists of specific receptors of calcitonin gene-related peptide (CGRP) receptor type 1 and ADM both potentiated the proliferation effect induced by aldosterone; and thiorphan, an inhibitor of the enzyme for ADM degradation, inhibited the adventitial [H]-thymine incorporation induced by aldosterone. ADM inhibited the activity of extracellular signal related kinase (ERK) stimulated by aldosterone. CONCLUSION: Aldosterone stimulates adventitia to produce and secrete ADM, which in turn, antagonizes the aldosterone-induced proliferation in adventitia.

Effects of adrenomedullin on cell proliferation in rat adventitia induced by lysophosphatidic acid.

Lysophosphatidic acid (LPA) is a bioactive phospholipid having growth factor-like activity on fibroblasts and is involved in cardiovascular diseases such as hypertension and heart failure by inducing vascular remodeling, characterized by fibroblast proliferation and migration in adventitia. Among various bioactive factors that LPA works with, adrenomedullin (ADM) is a multiple functional peptide with an important cytoprotective effect against cardiovascular damage. We studied rat aortic adventitia to explore the possible paracrine/autocrine interaction between endogenous ADM and LPA. LPA stimulation of the adventitia to secrete ADM and express its mRNA was concentration dependent. ADM inhibited LPA-induced proliferation in adventitial cells and attenuated the activity of mitogen-activated protein kinase (MAPK) stimulated by LPA. In contrast, treatment with specific antagonists of the ADM receptor potentiated the LPA-induced proliferation in adventitial cells. We concluded that LPA stimulates the adventitia to produce and secrete ADM, which in turn regulates the vascular biological effects of LPA.

Relationship between the contents of adrenomedullin and distributions of neutral endopeptidase in blood and tissues of spontaneously hypertensive rats.

Adrenomedullin (ADM) is a multifunctional peptide with important roles in the cardiovascular system, especially in the adjustment of cardiovascular and renal homeostasis. ADM is present in plasma, organs and tissues, and its activity increases during hypertension. It remains unknown whether the clearance of this peptide is altered during hypertension. Neutral endopeptidase (NEP) is the major enzyme in ADM's degradation. We observed the activity and distribution of NEP and the expression of its mRNA in the plasma, cardiac ventricle, aorta, jejunum and kidney of spontaneously hypertensive rats (SHRs) in order to study the possible role of NEP in elevating tissue ADM concentrations during hypertension. ADM and NEP were diffuse in all tissues studied. The level of tissue ADM was generally higher in SHR tissues than in control tissues, except in the renal medulla, and its mRNA expression was higher in all tissues. Plasma NEP activity, general NEP activity and the expression of NEP mRNA in the left ventricle, aorta and jejunum in SHRs was lower than that of controls, and the level of ADM was inversely correlated with NEP activity. NEP activity and mRNA and protein expression in SHR kidneys were higher than in control kidneys; moreover, the ADM content was positively correlated with NEP activity in the renal cortex. NEP activity in the lung of SHRs did not differ from that of controls. Thus, in SHRs, the local concentration and action of ADM in the tissues may be differentially regulated by NEP.

Relationship between contents of adrenomedullin and distributions of neutral endopeptidase in blood and tissues of rats in septic shock.

Adrenomedullin (ADM), a multifunction peptide with important roles in regulating cardiovascular homeostasis, has the vasodilatory properties and is of particular interest in the pathophysiology of sepsis. ADM levels in plasma and tissues are regulated by the proteolysis of neutral endopeptidase (NEP), the major enzyme of ADM degradation. We observed the NEP activity in the plasma, the activity and distribution of NEP and its mRNA expression in the tissues of rats in septic shock to study the possible role of NEP in elevating tissue ADM concentration during sepsis. ADM level increases progressively during sepsis except in the jejunum. Rats in early phase of shock (ES) showed diverse changes in tissue NEP activity. Plasma NEP activity, tissue NEP activity and its protein and mRNA expression in the left ventricle, aorta, jejunum and lung in the late phase of shock (LS) rats were lower than those in ES and the control, but no statistical change of NEP activity in the kidney was observed. The level of ADM was inversely correlated with NEP activity in the plasma, ventricle and aorta and positively correlated with NEP activity in the jejunum. Thus, in sepsis, the local concentration and action of ADM in tissues may be differentially regulated by NEP.