Search

Sluggish kinetics of methanol oxidation reaction (MOR) and alkaline hydrogen evolution reaction (HER) even on precious Pt catalyst impede the large-scale commercialization of direct methanol fuel cell (DMFC) and water electrolysis technologies. Since both of MOR and alkaline HER are related to water dissociation reaction (WDR), it is reasonable to invite secondary active sites toward WDR to pair with Pt for boosted MOR and alkaline HER activity on Pt. Mo2C and Ni species are therefore employed to engineer NiPt–Mo2C active site pairs, which can be encapsulated in carbon cages, via an in-situ self-confinement strategy. Mass activity of Pt in NiPt–Mo2C@C toward HER is boosted to 11.3 A/mgPt, 33 times higher than that of Pt/C. Similarly, MOR catalytic activity of Pt in NiPt–Mo2C@C is also improved by 10.5 times and the DMFC maximum power density is hence improved by 9-fold. By considering the great stability, NiPt–Mo2C@C exhibits great practical application potential in DMFCs and water electrolysers.

Efficient hydrogen production from water splitting was crucial for sustainable energy society and yet impeded by sluggish anodic water oxidation and urea oxidation had been considered as alternative reaction due to the much lower oxidation potential. Rational design of highly efficient cost-effective electrocatalysts for urea oxidation was therefore urgent for the development of hydrogen production from overall urea oxidation. Herein, the Ni/Mo2C@CN catalyst consisted of porous carbon shell and heterojunction Ni/Mo2C core was constructed by an in-situ self-confinement synthesis strategy. The mutual promotion effect of Ni and Mo2C can boost the urea oxidation and hydrogen evolution reactions at the same time. Only 1.51 V applied potential was needed to achieve stable 10 mA/cm2 overall urea oxidation on the Ni/Mo2C@CN catalyst. By considering the great stability resulted from the protection effect of the carbon shell, practical application potential of Ni/Mo2C@CN in overall urea oxidation was achieved.

Vertically oriented graphene (VG) is deposited on a wide range of substrates by plasma-enhanced chemical vapor deposition. Moreover, the growth mode of VG is proven to be bottom-up deposition using isotope labeling. The Raman characteristic features of rhodamine 6G (R6G), an aromatic dye, are acquired using VG as a universal fluorescence quencher. The fluorescence quenching mechanism is likely related to the transfer of energy and photon-excited electrons between dye molecules and VG because not only the fluorescence emission spectrum of R6G greatly overlaps with the UV–vis absorption spectrum of VG, but also the resistance of dye-coated VG decreases under light irradiation. In addition, the Raman features of other aromatic dyes, such as eosin Y, rhodamine B, methylene blue, and gallocyanine, are obtained by the same method.

Single atom catalysts (SACs) are emerging as a highly promising catalyst category in oxygen electrocatalysis; however, their real-world implementation in rechargeable zinc-air batteries (ZABs) is restricted by the insufficient bifunctional activity. Here, a secondary single-atom regulation strategy is developed to tailor the coordination environment and thus modify the catalytic behaviors of single atom Ni catalysts. Through introducing atomically dispersed Fe moieties, the coordination environment of single Ni atom is well regulated with a higher Ni-N/O coordination number due to the long-range electronic penetration interaction, which triggers more optimized adsorption strength between active sites and reaction intermediates. As a result, the obtained Fe, Ni dual atom catalyst (FeNi-SAs@NC) requires only 298 mV overpotential to deliver 10 mA cm−2 in oxygen evolution reaction (OER) catalysis outperforming the benchmarking IrO2 (313 mV), Fe-SAs@NC (335 mV) and Ni-SAs@NC (356 mV) electrocatalysts. Moreover, FeNi-SAs@NC performs superior oxygen reduction reaction (ORR) activity to the single-atom counterparts and Pt/C benchmark. The practical application of the FeNi-SAs@NC is further validated by a higher ZAB performance (260 mW cm−2 vs 71 mW cm−2 for Pt/C-IrO2), improved long-term durability (100 h at 20 mA cm−2) and encouraging performance in all-solid-sate ZABs (70 mW cm−2).

With PWA as proton transfer and silica as water retainer, stable phosphotungstic acid/silica/Nafion (PWA/Si–N) composite membrane is non-destructively fabricated and exhibits excellent stability and high temperature proton conductivity. Compared with pristine Nafion, high temperature proton conductivity is significantly enhanced due to the collaboration between –SO3H ionic clusters and the in-situ filled silica embedded PWA nanoparticles. PWA is stabilized in the ionic clusters via in-situ catalyzing the hydrolysis silica precursor targeted filled into the –SO3H ionic clusters. Stable proton conductivity of the PWA/Si–N membrane at 110 °C and 60% RH is high to 0.058 S/cm, which is 2.4 folds of that of Nafion. At the same time, the composite membrane still maintains good mechanical and thermal stability. As a result, high temperature fuel cell performance of the composite membrane is improved by 41% compared with the pristine Nafion membrane. The in-situ coating method proved to be an effective method to solve the stability of PWA in Nafion membrane, especially the inorganic oxide with good hygroscopicity as the modifier.

The fabrication of mixed matrix membranes (MMMs) for pervaporation recovery of butanol from aqueous solutions is garnering significant attention. However, constructing highly continuous metal–organic frameworks (MOFs) with reasonable loading as molecular pathways in MMMs using a scalable, mature, and controlled solution casting strategy remains challenging. We developed a novel advanced pearl necklace-like zeolitic imidazolate framework (ZIF) threaded by polypyrrole (PPy) nanotubes (ZIF-8@PPy) using a simple green approach. The inclusion of pearl necklace-like ZIF-8 throughout a PDMS matrix created micron-sized ultrahighly continuous multiple guest molecule transport channels for pervaporation separation and significantly reduced the voids and defects caused by agglomeration. For 1 wt% n-butanol aqueous solutions, the resultant MMMs with 20 wt% ZIF-8@PPy improved the separation factor from 36.4 to 70.2 while simultaneously increasing the total flux from 312.4 to 564.8 g m−2 h−1. The transport mechanism was resolved by simulation and experiments to examine the significant increase in the membrane permeability (from 31.8 to 125.2) and selectivity (from 2.3 to 4.8). The PPy nanotubes effectively inhibit the movement of water molecules and increase the fractional free volume without changing the internal regular structure of ZIF-8. The pearl necklace-like ZIF-8 with high sequence and structural integrity can be applied to prepare defect-free membranes with excellent performance for sustainable applications in petroleum, chemical, medicinal industries, or environmental protection. We also anticipate that this ultrahighly continuous MOF configuration can be extended to various other MOFs and applications.

Co, N co-doped carbon (CoN@C) with properly engineered heteropores was facilely synthesized using metal carbonate hydroxides as metal precursor and multistage porogen. CoN@C therefore exhibits superior ORR catalytic activity with a half-wave potential of 0.876 V vs. RHE, and the CoN@C-based zinc-air battery can be stably cycled for 100 h.

Based on the swelling-filling modification strategy, Nafion/silica composite membrane is facilely fabricated by non-destructively filling silica nano-particles into the Nafion framework. High temperature proton conductive performance of modified Nafion membrane is significantly enhanced due to the synergistic effect of maintaining the ordered nanophase-separated structure in Nafion and excellent water retention capacity of the silica fillers. Proton conductivity of the composite membrane is therefore raised to 33 mS/cm at 110 °C and 60% RH, which is enhanced by ca. 30% compared with the pristine Nafion. Taking account into the improved mechanical and oxidative stabilities attributed to the hydrogen bonding interaction between silica nano-particles and Nafion chains, high temperature fuel cell performance is measured and found to be remarkably improved by 37% at low humidity by considering the power density.

China has huge potential on biogas resources and the distributed energy system (DES) based on micro gas turbine provides an effective way for biogas utilization. In this work, turbulent combustion characteristics in the combustor of micro gas turbine for DES were numerically and experimentally studied, and the effect of carbon dioxide content in biogas on the turbulent flame was mainly analyzed. Turbulent flames structures of natural gas and three kinds of biogas under various equivalence ratios were measured by three-dimensional (3D) combustion diagnostic technique based on computed tomography of chemiluminescence (CTC). The results show that the carbon dioxide content in the fuel has a great influence on flame structure of turbulent combustion. The increase of carbon dioxide content in the fuel not only reduces turbulent combustion rate, but also makes the combustion stability worse. With the decrease of equivalence ratio, the effect becomes greater. With the increase of carbon dioxide volume fraction, combustion flame is gradually away from the outlet of the nozzle. When volume fraction of carbon dioxide is 50%, the distance between the combustion flame and the nozzle outlet increases the 100 mm. Furthermore, carbon dioxide weakens the effect of excess air on the CH* distribution and turbulent flame.

The corrosive issues are comprehensively caused in oilfield rejection system, in which sulfide is one of (bio-)chemical factors leading to high corrosive rate and blocking problem. Generally, aerobic treatment is a well-established and cost-effective unit for sulfide removal before oilfield wastewater reinjection. However, the residual dissolved oxygen (DO), which causes chemical, biological and electrochemical corrosion to water injection pipeline equipment, is still high after multi-stage filtration of DO removal. Here, a novel system to achieve quick and efficient DO removal through a three-electrode (cathode-anode-cathode)-upflow bioelectrochemical reactor (RCAC) was constructed before wastewater reinjection. Bioelectrodes were well established by utilizing organic matters of oilfield wastewater and conducted extracellular electron transport to achieve a steady DO removal from ∼5 mg/L to 0.01 mg/L (HRT 6 h), the DO removal efficiency reached approximately 100%, and the downside biocathode made the largest contribution for DO removal. In the treated wastewater, the corrosion rate of stainless steel N80 ultimately declined over 30 days testing. As a result of DO removal and ammonia conversion to nitrate by bioelectrodes, the corrosive microorganisms were substantially changed. Especially, sulfate-reducing bacteria (SRB) on the surface of N80 immersed in treated wastewater were decreased in abundance; while nitrate-reducing bacteria (NRB) enriched more, which can compete with SRB to prevent biological corrosion.

Efficient electrocatalysts for the hydrogen evolution reaction (HER) in both acidic and alkaline media are prominently important to advance the widespread application of industrial water splitting technology. In this work, we have synthesized ultrasmall rhodium–rhodium phosphide hetero-nanoparticles (3.4 nm, Rh–Rh2P@C) by partial phosphorization of Rh@C at 300 °C together with Na2HPO2. The constructed Rh–Rh2P@C requires only 24 mV and 37 mV overpotentials to reach 10 mA m−2 in 0.5 M H2SO4 and 1 M KOH electrolytes, which are lower than those of Rh@C and Rh2P@C due to the formation of heterointerfaces inducing modulation of local electronic structures and more active sites; as a result, a more moderate hydrogen adsorption–desorption strength is achieved for Rh–Rh2P@C as proved by theoretical calculation. Moreover, the calculated mass activity of Rh–Rh2P@C is 4 orders of magnitude higher than that of the benchmark Pt/C electrocatalyst. Besides, exceptional stability is recorded for Rh–Rh2P@C in both acidic and alkaline electrolytes due to the strong electronic interaction between Rh and Rh2P. This study offers a new strategy to manufacture efficient electrocatalysts for various applications.

Tuning electrocatalysts via interface engineering is widely adopted as a valid way to manipulate the electrocatalytic activity. Herein, the interface engineering of PdCu aerogels is successfully achieved by the integration of an ionic liquid (IL), which not only accelerates the gelation kinetics but also leads to the modulation of the interface electronic properties, enabling IL functionalized PdCu aerogels (IL/PdCu) as advanced electrocatalysts for the methanol oxidation reaction (MOR) with splendid electrocatalytic activity. Density functional theory (DFT) calculations also demonstrate that IL-involved interface engineering dramatically reduces the chemisorption energy of CO-containing intermediates and thus significantly boosts the MOR performance. Furthermore, direct methanol fuel cells (DMFCs) using an IL/Pd3Cu1 anode catalyst exhibit a higher power density than those containing Pd3Cu1 and commercial Pd catalysts. This work highlights the superiority of designing advanced electrocatalysts by interface engineering.

Chronic wound repair is a common complication in patients with diabetes mellitus, which causes a heavy burden on social medical resources and the economy. Hypaphorine (HYP) has good anti-inflammatory effect, and chitosan (CS) is used in the treatment of wounds because of its good antibacterial effect. The purpose of this research was to investigate the role and mechanism of HYP-nano-microspheres in the treatment of wounds for diabetic rats. The morphology of HYP-NPS was observed by transmission electron microscopy (TEM). RAW 264.7 macrophages were used to assess the bio-compatibility of HYP-NPS. A full-thickness dermal wound in a diabetic rat model was performed to evaluate the wound healing function of HYP-NPS. The results revealed that HYP-NPS nanoparticles were spherical with an average diameter of approximately 50 nm. The cell experiments hinted that HYP-NPS had the potential as a trauma material. The wound test in diabetic rats indicated that HYP-NPS fostered the healing of chronic wounds. The mechanism was through down-regulating the expression of pro-inflammatory cytokines IL-1β and TNF-α in the skin of the wound, and accelerating the transition of chronic wound from inflammation to tissue regeneration. These results indicate that HYP-NPS has a good application prospect in the treatment of chronic wounds.

Summary We investigated the short-term dynamics of microbial composition and function in bioreactors with inocula collected from full-scale and laboratory-based anaerobic digestion (AD) systems. The Bray-Curtis dissimilarity of both inocula was approximately 10% of the predicted Kyoto Encyclopedia of Genes and Genomes pathway and 40% of the taxonomic composition and yet resulted in a similar performance in methane production, implying that the variation of community composition may be decoupled from performance. However, the significant correlation of volatile fatty acids with taxonomic variation suggested that the pathways of AD could be different because of the varying genus. The predicted function of the significantly varying genus was mostly related to fermentation, which strengthened the conclusion that most microbial variation occurred within the fermentative species and led to alternative routes to result in similar methane production in methanogenic bioreactors. This finding sheds some light on the understanding of AD community regulation, which depends on the aims to recover intermediates or methane., Graphical abstract, Highlights • The variation of the community was decoupled from AD performance • The fermentative intermediates affect AD pathway rather than the AD performance • The redundancy of fermentative species induces the independent community variation, Biological sciences; Biomass; Biotechnology; Chemical engineering; Microbiology

Macrophages are myeloid immune cells, present in virtually all tissues which exhibit considerable functional plasticity and diversity. Macrophages are often subdivided into two distinct subsets described as classically activated (M1) and alternatively activated (M2) macrophages. It has recently emerged that metabolites regulate the polarization and function of macrophages by altering metabolic pathways. These metabolites often cannot freely pass the cell membrane and are therefore transported by the corresponding metabolite transporters. Here, we reviewed how glucose, glutamate, lactate, fatty acid, and amino acid transporters are involved in the regulation of macrophage polarization. Understanding the interactions among metabolites, metabolite transporters, and macrophage function under physiological and pathological conditions may provide further insights for novel drug targets for the treatment of macrophage-associated diseases. In Brief Recent studies have shown that the polarization and function of macrophages are regulated by metabolites, most of which cannot pass freely through biofilms. Therefore, metabolite transporters required for the uptake of metabolites have emerged seen as important regulators of macrophage polarization and may represent novel drug targets for the treatment of macrophage-associated diseases. Here, we summarize the role of metabolite transporters as regulators of macrophage polarization.

Developing efficient, durable, and economical electro-catalysts for large-scale commercialization of hydrogen evolution (HER) is still challenging. Herein, we report for the first time, to the best of our knowledge, a Pd-based ternary metal phosphide as an active and stable HER catalyst. The face-centered-cubic Pd–Ni–P nanoparticles (NPs) annealed at 400 °C show the best HER activity with a low overpotential of 32 mV to realize a current density of 10 mA cm−2 and a high mass activity of 1.23 mA μg−1Pd, superior to Pd NPs, Pd–P NPs, Pd–Ni NPs, and Pd–Ni–P NPs annealed under different temperatures. Moreover, this catalyst is also highly stable during 20 h of continuous electrolysis. Notably, the easily fabricated Pd–Ni–P NPs are among the most active Pd-based HER catalysts. This work indicates that Pd-based metal phosphides could be potentially applied as a type of practical HER catalyst and might inform the fabrication of analogous materials for hydrogen-related applications.

Sulfonated covalent organic nanosheets (SCONs) with a functional group (−SO3H) are effective at reducing ion channels length and facilitating proton diffusion, indicating the potential advantage of SCONs in application for proton exchange membranes (PEMs). In this study, Nafion-SCONs composite membranes were prepared by introducing SCONs into a Nafion membrane. The incorporation of SCONs not only improved proton conductivity, but also suppressed methanol permeability. This was due to the even distribution of ion channels, formed by strong electrostatic interaction between the well dispersed SCONs and Nafion polymer molecules. Notably, Nafion-SCONs-0.6 was the best choice of composite membranes. It exhibited enhanced performance, such as high conductivity and low methanol permeability. The direct methanol fuel cell (DMFC) with Nafion-SCONs-0.6 membrane also showed higher power density (118.2 mW cm−2), which was 44% higher than the cell comprised of Nafion membrane (81.9 mW cm−2) in 2 M methanol at 60 °C. These results enabled us to work on building composite membranes with enhanced properties, made from nanomaterials and polymer molecules.

In order to reveal the contribution of carbon support in metal oxide-based catalysts for the oxygen evolution reaction (OER), the active carbon is facilely functionalized with various active groups and composite with Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF). By systemically investigating the electrochemical catalytic properties of the composite catalysts, it can be found that the enhancement in the OER activity of BSCF is mainly attributed to the co-catalysis effect with the OER process altered. The effect of carbon support on the electron conductivity improvement, which is widely considered in electrochemical systems, can be ignored during the OER catalysis on the rotating disk electrode. Functionalization with proper groups of the carbon support is, therefore, considered to be an effective and facile strategy to further improve the OER activity of metal oxide-based catalysts.

This work aimed to improve sludge disintegration and nutrient solubility using synergism of a surfactant (sodium dodecylbenzene sulfonate (SDBS)) and ultrasound. The results illustrated that the critical micelle concentration (CMC) of the surfactant (0.025 g SDBS/g total solid (TS)) was significantly related to the cost-effective pre-treatment performance. The particle sizes of Dx(10) and Dx(50) were decreased from 16.4 μm and 55.4 μm to 3.69 μm and 12.9 μm, respectively, under a 600 W ultrasound input with the CMC of SDBS. As the surfactant dosage was further increased (0.05 SDBS g/g TS), the maximum increment rates of total nitrogen (TN) and total phosphorus were obtained at 1250.1% and 197.1%, respectively. However, higher pre-treatment efficiency could be achieved when SDBS was below the CMC. It related to the decrease of surface tension. Based on the economic evaluation, the total cost significantly increased when the amount of surfactant was greater than the CMC.

Phosphorus contained metallic 1T-MoS2 produced from in-situ ammonium intercalation induced surface sulfur atom distortion of MoS2 rooted in N,P,S-codoped hierarchical flowerlike carbon (HCMF) hybrids were successfully prepared via a dopamine self-polymerization together with molybdate process followed by a hydrothermal reduction route. On account of the coupling effect of metallic phase, defect-rich character, heteroatomic dopants and highly conductive carbon support, the P-MoS2@HCMF demonstrates prominent performances with an overpotential of merely 86 mV to deliver a current density of 10 mA cm–2 and a small Tafel slope of 42.35 mV dec–1 for hydrogen evolution reaction (HER) in 0.5 M H2SO4, which are among the best results for molybdenum disulfide based HER catalysts. Strikingly, benefiting from S vacancies and P dopant functioning as electron donors, as well as strain arisen from the tensile of rigid carbon microflower scaffold to MoS2 nanosheets to overcome agglomeration barriers of nanosheets, P-MoS2@HCMF remained well the pristine 1 T phase and exhibited superior cycling stability with indistinguishable overpotential decay over 5000 sweeps and extraordinary HER durability during the 100 h long-term operation with negligible current deterioration. These findings highlight the prospective potential of P-MoS2@HCMF as a highly efficient and stable noble metal-free electrocatalyst towards HER.

The underlying dynamics of microbial (bacteria and archaea) communities ecologically responding to an applied potential are critical to achieving the goal of enhancing bioenergy recovery but are not sufficiently understood. We built a MEC-AD mode that increased methane production rate by several times (max. 3.8 times) during the startup period compared to control AD, changed the absence or presence of external voltage to provide the pre-, dur-, and post- samples for microbial analysis. From a time and spatially dependent community analysis of electrode-respiring bacteria and methanogens, the corresponding Geobacter developed under the influence of external voltage, pairing with methanogens in the anodic and cathodic biofilm to generate methane. Additionally, at the cathode, the Alkaliphilus (basophilic bacteria) also correspondingly shifted alongside the change of external voltage. The mcrA sequencing confirmed a change in the dominant microbe from acetoclastic (mostly Methanosarcina mazei LYC) to hydrogenotrophic methanogens (mostly basophilic Methanobacterium alcaliphilum) at the cathode with 0.8 V voltage. Overall, the external voltage not only enriched the functional microbes including electrogens and methanogens but also indirectly shifted the composition of the bacterial and archaeal community via disturbing the pH condition. The predictive functional profiling indicated that the cathodic methanogenesis principally followed the metabolism pathway of the hydrogenotrophic methanogens, suggesting the F420 co-enzyme could be the key mediate for electron transfer. All data suggested that the electric stimulation would change and maintain the micro-environmental conditions to shift the bacterial/archaeal community.

Copper-doped zinc sulfide quantum dots embedded in silica films (ZnS:Cu/SiO2) have been synthesized by sol-gel dip-coating with subsequent thermal annealing. The considered Cu/Zn molar ratios ranged from 0.2% to 2%. Atomic force microscopy analysis shows mostly a granular nanostructure of the deposited films with a roughness less than 30 nm depending on Cu content; i.e. the lowest value of 14 nm is obtained for 0.5% Cu doping. The mean particle size of ZnS:Cu quantum dots (QDs) has been found to be around 2.5 nm as measured by UV–Vis spectroscopy, in agreement with the value of 3 nm estimated by Scherrer equation using X-ray diffraction patterns. Photoluminescence (PL) spectra reveal new features regarding the intensity and width of the peaks. Two well-resolved emission bands are essentially observed in the blue and green regions centered respectively at 438 nm and from 510 to 514 nm. The blue band shows a variation of width with Cu content and a quenching of PL at 2% Cu doping. At 0.5% Cu, a PL line-width of approximately 3 nm is measured for this blue band. Contrarily to the blue emission, the green band is not quenched at 2% Cu content. Finally, the origin of the PL bands has been discussed.

Here, we report a stable tungsten carbide hollow microsphere (W2C-HS) electrocatalyst with robust electrocatalytic activity toward hydrogen evolution reaction fabricated from carburization of tungsten oxides at 700 °C with CH4/H2 flow, which demands overpotentials of 153 and 264 mV to deliver 10 and 100 mA cm–2 ascribing to the hollow structures beneficial for interfacial charge transfer as well as releasing of hydrogen molecular. Meanwhile, the W2C-HS electrocatalyst exhibits undetectable degradation after 20 000 potential cycles indicative of extraordinary durability; in contrast, overpotential@100 mA cm–2 is dramatically increased from 128 to 251 mV after only 2000 potential cycles for benchmark platinum electrocatalyst.

Large-scale hydrogen production from industrial electrolysis technology is challenged by sluggish hydrogen evolution reaction (HER) kinetics under alkaline conditions, even with Pt as catalyst. In consideration of the synergistic effects of Ru on water dissociation and Ru2P on proton reduction, Ru/Ru2P interfaces were engineered in situ via a high-pressure phosphorization strategy with phosphine as both a phosphorus source and reactant. The Ru/Ru2P-loaded P-doped carbon (Ru–Ru2P/PC) catalyst therefore exhibited superior alkaline HER activity compared to the Pt catalyst. The overpotential of the Ru–Ru2P catalyst to drive a 50 mA cm−2 alkaline HER was reduced by 65 mV compared to the Pt/C catalyst, and the loading of noble metal was much lower. Thus, the mass activity was doubled. With its great stability under alkaline conditions, the easily synthesized Ru–Ru2P catalyst shows promising application potential in industrial electrolysis systems.

Autotrophic denitrification can be driven using zero valent iron (ZVI) as an electron donor. Balancing the competitive reactions of abiotic nitrate removal and biotic nitrate removal by H2 is the key problem for iron-assisted autotrophic denitrification. Hence, H2 production by ZVI corrosion plays an important role in the iron-assisted nitrate reduction process, which determines the nitrate reduction rate and the end product. However, few studies concentrate on the effect of soluble H2 on ZVI corrosion and the performance of iron-assisted autotrophic denitrification. A hydrogen-rich solution is obtained by dual-chamber MFCs, which is usually directly discarded. The present study aimed to demonstrate that the dissolved hydrogen can be feasibly applied in iron-assisted autotrophic denitrification to accelerate nitrate reduction during ZVI corrosion. It was observed that a continuous dissolved hydrogen supply via electrolysis promoted and stabilized the performance of iron-assisted autotrophic denitrification. The average nitrate removal was 47.3% ± 0.2% in ZVI reactors with dissolved hydrogen-rich water (DH reactors), and 30.2% ± 0.3% in ZVI reactors without dissolved hydrogen-rich water (control reactors). Moreover, the concentration of nitrite was 0.04 mg L−1 in the DH reactors compared with 0.50 mg L−1 in the control reactors. No other intermediates (e.g. N2O) were found in both the autotrophic denitrification reactors. Finally, the hydrogen-rich water enriched the denitrifying bacteria and increased the abundance of specific functional genes, resulting in the promotion of hydrophobic denitrification during the iron-assisted nitrate removal.

W/W2C heterostructured nanoparticles encapsulated by N,P dual-doped carbon (W/W2C@NPC) fabricated by the carbonization of in situ polymerized polyaniline (PANI) and phosphotungstic acid require low overpotentials of 55 mV and 82 mV vs. RHE to achieve a cathodic current density of 10 mA cm-2 in acidic and alkaline electrolytes, respectively.

Metal nanoparticles (NPs) are prone to Ostwald ripening, which usually leads to a quick loss of the catalytic activity. Herein, we report a bottom-up synthesis of Pd35Ni1 sub-microcages (MCs) as a self-supported catalyst for the methanol oxidation reaction (MOR), showing excellent activity and durability. The key is to use a phosphine oxide as a weak capping agent to allow the aggregation of Pd–Ni NPs. The subsequent thermal ripening of the assembled NPs leads to the formation of the Pd–Ni MCs. Due to the high porosity, electrical conductivity, and atomically stepped surfaces, these MCs afford a current density of 3.2 mA cmPd−2 in the MOR in an alkaline medium, which is superior to those of Pd–Ni NPs and Pd NPs. Thanks to the well-defined bicontinuous self-supported structure, more than 91.4% of the current remained after 2000 cyclic voltammetry cycles. The excellent catalytic durability makes the MCs superior to the carbon-supported NP catalysts. This work provides a facile and environmentally benign approach to fabricate porous precious metallic nanomaterials as a highly active and durable electrocatalyst with enhanced utilization of the precious metals.

This study aims to compare the effects of different Fe stress on anammox (anaerobic ammonium oxidation) process, therefore seven identical reactors were operated under different Fe(II)/Fe(III) concentrations. After 38 days of operation, the anammox activity was highest (10.49 ± 0.41 mg-TN/(g-VSS·h)) under conditions of 5 mg/L-Fe(II), while under 30 mg/L-Fe(III) displayed severe inhibition. The results showed that continuous addition of 30 mg/L-Fe(III) would damage the composition of EPS (extracellular polymeric substances) and make anammox bacteria more sensitive to environmental stress. While high Fe(II) concentrations could result in precipitates encasing granular sludge, affecting substrate utilization. Moreover, the results of ΔNO3--N/ΔNH4+-N indicated that Fe(II)-dependent nitrate reduction was induced in reactors added with Fe(II). OM27_clade and norank_f__Burkholderiaceae might be candidates for this process according to the correlation of genera and functional genes (based on the PICRUSt 2 functional prediction). Overall, this research is expected to provide new ideas to the effects of Fe(II)/Fe(III) on anammox and to the practical application of coupled system based on anammox in wastewater treatment.

Although plant diseases generally cause more severe symptoms under conditions of high temperature and high humidity(HTHH), how plant respond to pathogen attack under this condition remains elusive.As an example, we herein comparatively studied pepper(Capsicum annuum) immunity against Ralstonia solanacearum under HTHH and ambient temperature by approaches of reverse genetics. We found that pepper respond to R.solanacearum infection by activating salicylic-acid- and jasmonic-acid-mediated immunity at ambient temperature. Under HTHH, However, it no longer activates JA-mediated immunity and activates only transient SA signaling at the early stage of R.solanacearum infection, but instead induces cytokinin mediated immunity.These two immune systems are positively regulated by CaWRKY40 via binding the WT-box and a novel W-box like (WL) box, respectively, in an environment-dependent manner: CaWRKY40 is activated upon R. solanacearum infection under HTHH, thereby upregulating ISOPENTENYLTRANSFERASE5(IPT5). The resulting cytokinin then works synergistically with CaWRKY40 in activating a subset of glutathione S-transferase genes via chromatin activation and WL-box binding, but prevent CaWRKY40 from activating ISOCHORISMATE SYNTHASE1 (ICS1) or SA-/JA-dependent pathogenesis-related genes by chromatin inactivation or by blocking WT-box binding.These results highlight the specific pepper immune response to R. solanacearum infection under HTHH and its synergistic activation by CaWRKY40 and cytokinins.

Large-scale application of zinc air batteries (ZABs) is impeded by the lack of efficient and cost-effective bifunctional oxygen catalysts. In this work, hetero-porous is rationally engineered for the carbon encapsulated CoFe catalyst, which is highly active toward both oxygen evolution reaction (OER) and oxygen evolution reaction (ORR). The hs-CoFe catalyst with “plate reactor” structure is facilely synthesized by combining the selective etching and reduced graphene oxide supporting to construct pores with size of 10–100 nm and 100–1000 nm, respectively, for smooth mass transfer. OER/ORR activities are significantly boosted, and difference between the potential to deliver 10 mA/cm2 OER and half wave potential of ORR is therefore lowered to 0.608 V while this potential difference of Pt/C-IrO2 is 0.732 V. The corresponding ZAB exhibits a maximum power density of 232 mW/cm2, which sheds light on providing a novel strategy for oxygen reaction catalyst designation.

Sulfate radicals produced by ultrasonic activation of persulfate (PS) or sulfate were applied to disintegrate sludge flocs and extracellular polymeric substances (EPSs). The pretreatment facilitated the production of volatile fatty acids (VFAs) and hydrogen from subsequent anaerobic fermentation, yielding a potential method for improving the utilization of sulfate-containing waste-activated sludge (WAS). Sulfate radicals produced using ultrasound (US) in the presence of PS/sulfate showed a synergetic effect of advanced oxidation on WAS pretreatment. Among the three types of pretreatment (US, US + Sulfate, and US + PS), US + PS pretreatment was the most favoured for chemical oxygen demand (COD) solubilization, protein release, and sludge disintegration under a US density of 1.5 W/mL. Tightly bound EPS (TB-EPS) could be effectively disintegrated, and organic compounds were transformed into loosely bound EPS and soluble EPS. Unexpected COD consumption by excessive free radicals was also observed, when increasing the ultrasonic energy input (e.g. to 12 W/mL), towards a positive role for sludge disintegration and subsequent anaerobic fermentation. It was found that small particles (0.1–0.5 μm) from released organics could be preferentially overoxidized. An appropriate low ultrasonic strength initiated attack on the polymeric substances in WAS by the produced radicals, which TB-EPS could be primary target.

A palladium phosphide electrocatalyst supported on carbon black (PdP2 @CB) shows efficient water splitting in both alkaline and neutral electrolytes. Significantly lower overpotentials are required for PdP2 @CB (27.5 mV in 0.5 m H2 SO4 ; 35.4 mV in 1 m KOH; 84.6 mV in 1 m PBS) to achieve a HER electrocatalytic current density of 10 mA cm-2 compared to commercial Pt/CB (30.1 mV in 0.5 m H2 SO4 ; 46.6 mV in 1 m KOH; 122.7 mV in 1 m PBS). Moreover, no loss in HER activity is detectable after 5000 potential sweeps. Only 270 mV and 277 mV overpotentials are required to reach a current density of 10 mA cm-2 for PdP2 @CB to catalyze OER in 1 m KOH and 1 m PBS electrolytes, which is better OER activity than the benchmark IrO2 electrocatalyst (301 mV and 313 mV to drive a current density of 10 mA cm-2 ). 1.59 V and 1.72 V are needed for PdP2 @CB to achieve stable water splitting catalytic current density of 10 mA cm-2 in 1 m PBS and 50 mA cm-2 in 1 m KOH for 10 h, respectively.

Based on a swelling-filling modification strategy, sheared graphene oxide (SGO) sheets are in-situ inserted into the Nafion membrane and act as bi-functional fillers to simultaneously improve the methanol-permeation resistivity and proton conductivity. Proton/methanol selectivity, as a key descriptor of overall performance of the proton exchange membrane, of the Nafion membrane is therefore 4-fold increased. At the same time, the mechanical, oxidative and thermal stabilities of the Nafion membrane are also improved by the SGO sheets due to the interaction between SGO and Nafion. As a result, the swelling-filling modified SGO -Nafion membrane is therefore considered as a promising electrolyte for direct methanol fuel cell (DMFC) application and the power of the Nafion based DMFC can be improved by ca. 50% during the polarization measurement.

Elevated atmospheric temperature and CO2 concentration ([CO2]) can strongly affect yield, CH4 and N2O emissions in rice paddies. However, understanding of their response to combined temperature and [CO2] increases under field conditions is still limited. To study this issue further, an open-top chamber (OTC) platform was set up to simulate two levels of atmospheric temperature (ambient and 2 °C elevated) and two levels of [CO2] (ambient and 60 ppm elevated) during two rotations of double rice, including twelve independent OTCs and three un-chambered open field sites as trial plots. The experimental site is located in Hubei Province, Central China, which has a subtropical monsoon climate. In all four rice seasons, elevated CO2 induced an increment in grain yield by 11.4–19.7%, while also enhancing CH4 and N2O emissions by 19.8–52.6% and 102.4–140.0%, respectively, compared with ambient temperature and [CO2]. Elevated temperature enhanced CH4 emissions by 4.4–36.0%, and decreased N2O emissions by 1.5–10.5% in three rice seasons. Elevated temperature had different effects on grain yield, with a reduction of 1.0–3.2% in early rice and an increase of 6.3–9.2% in late rice. When elevated temperature and [CO2] were combined, there was a positive interaction that further enhanced CH4 emissions and yield of late rice, and an offsetting effect on N2O emissions and yield of early rice. Over the 2-year experiment, warming and CO2 enrichment caused an increase of 9.3–44.2% in greenhouse gas intensity, suggesting that more greenhouse gas emissions will be emitted to produce a unit mass of rice under projected global warming. These findings provide initial data for the estimation of CH4 and N2O emissions under elevated temperature and [CO2] in double rice cropping system, and stress the need for effective management practices that promote rice yield while reducing greenhouse gas emissions.

Epitaxially-oriented large-scale monolayer molybdenum disulfide (MoS2) grown directly on graphene (Gr) with an atomic-clean interface draws intensive interest in both areas of fundamental sciences and electronic-device applications. In general, however, synthetic characteristics and bandgap-related properties of MoS2 crystals can be varied by the selection of substrates that support Gr, and mechanisms that govern these phenomena remain unclear. Here, by means of scanning tunneling microscope and spectroscopy (STM/STS) and photoluminescence (PL) measurements, we have discovered that considerably-strained Gr can strongly affect the epitaxy of MoS2 crystals and enhance the interlayer electronic coupling between monolayer MoS2 and its Gr-platinum (Pt) substrate, leading to the stack of MoS2 layers and a narrowing direct bandgap of monolayer MoS2. Our studies shed light on growing large-scale MoS2 films on Gr and the bandgap modulation in these heterostructures.

Pure ZnO and a series of Al and Er co-doped ZnO nanomaterials (AEZ) have been synthesized and characterized by various analytical and spectroscopic techniques such as TEM, EDS, XRD, FTIR, Raman, UV–Vis and SQUID. Al concentration has been varied from 1, 2 and 3% keeping fixed concentration of Er at 2% to obtain the co-doped ZnO. TEM images show uniform and homogeneously distributed plates-like nanostructure for ZnO and predominately spherical shape with hexagonal facets for AEZ. XRD Rietvield analysis confirms the crystallinity of ZnO and AEZ with ZnO wurtzite crystal structure. It also clearly demonstrates the coexistence of Al and Er into ZnO lattice as evidenced by the shift of reflections towards lower 2θ values. The change of magnetic behavior from ferromagnetic into paramagnetic originated from point defects depending on the concentration of the doping elements. The as-prepared nanopowders have been tested under visible light (554 nm wavelength) irradiation to evaluate the photocatalytic activity towards Rhodamine B (RhB); the degradation rate was found to be more than 93% in 40 min with the combination 3% Al, 2% Er co-doped ZnO.

The combined impacts of modified nitrogen (N) fertilizers and water saving irrigation (WSI) on greenhouse gas (GHG) emissions and grain yield of rice paddies have not previously been documented. GHG emissions from rice paddies under modified N fertilizers and WSI deserve attention because water and N are being used extensively to attain higher grain yield. A field experiment was conducted to evaluate the influence of modified N fertilizers and WSI on methane (CH4) and nitrous oxide (N2O) emissions and grain yield in rice paddies. Four treatments were applied: urea with conventional irrigation (U + CI), urea with shallow water depth with alternate wetting-drying water saving irrigation (U + SWD), polymer-coated controlled release urea with SWD (CRU + SWD), and nitrapyrin-urea composition plus hydroquinone with SWD (NU + HQ + SWD). Compared to U + CI, CH4 emissions significantly decreased by 26% and 31%, and N2O emissions increased by 52% and 42% under U + SWD in the early and late rice growing seasons respectively (p

A non-destructive swelling-filling (SF) strategy is applied for inorganic modification on Nafion by using functionalized silica (F-silica) nanoparticles as fillers. With the facilely prepared F-silica gel as SF treating agent, the mono-dispersed F-silica nanoparticles can in-situ insert into the Nafion membrane and tightly anchor on the Nafion chains through the hydrogen bonding interaction between the oxygen containing groups on F-silica fillers and –SO3H group on Nafion chains. The F-silica nanoparticles act as bi-functional fillers in the modified Nafion membrane to improve proton conductive and methanol-permeation resistive performances simultaneously. 100% enhanced proton/methanol selectivity therefore leads to a more than 30% improved direct methanol fuel cell (DMFC) performance in terms of power output. By considering the great mechanical, thermal and oxidative stabilities comprehensively, the F-silica-Nafion membranes exhibit promising application potential for high-energy DMFC application.

A formic acid oxidation electro-catalyst with ultra-low palladium (Pd) loading was prepared via an ionic exchange method by utilizing the acidic functional groups on graphene oxide (GO). After simultaneous reduction of exchanged Pd2+ and residual functional groups on the GO surface, an ionic exchange reduced Pd catalyst supported on reduced GO (IE-Pd/rGO) was obtained. Three times improved formic acid oxidation mass activity compared with that of the conventional synthesized Pd/C catalyst was exhibited for the IE-Pd/rGO catalyst. More importantly, formic acid oxidation stability on the IE-Pd/rGO catalyst was remarkably improved due to synergistic effect of the strong immobilization of Pd nanoparticles and the effect of in situ doped N on the rGO support.

Defect-rich tungsten disulfide (WS2) nanosheets are synthesized via a self-template method, in which tungsten oxide is partially sulfurized to form WS2/WO3 nanosheets. The defect-rich WS2 nanosheets only require an overpotential of 145 mV to achieve a current density of 10 mA cm-2 with a Tafel slope of 58.5 mV dec-1 and exhibit excellent stability in 0.5 M H2SO4 electrolyte.

The coupling strength between two-dimensional (2D) materials and substrate plays a vital role on thermal transport properties of 2D materials. Here we systematically investigate the influence of vacuum thermal annealing on the temperature-dependence of in-plane Raman phonon modes in monolayer graphene supported on silicon dioxide substrate via Raman spectroscopy. Intriguingly, raising the thermal annealing temperature can significantly enlarge the temperature coefficient of supported monolayer graphene. The derived temperature coefficient of G band remains mostly unchanged with thermal annealing temperature below 473 K, while it increases from −0.030 cm−1/K to −0.0602 cm−1/K with thermal annealing temperature ranging from 473 K to 773 K, suggesting the great impact of thermal annealing on thermal transport in supported monolayer graphene. Such an impact might reveal the vital role of coupling strength on phonon scattering and on the thermal transport property of supported monolayer graphene. To further interpret the thermal annealing mechanism, the compressive stress in supported monolayer graphene, which is closely related to coupling strength and is studied through the temperature-dependent Raman spectra. It is found that the variation tendency for compressive stress induced by thermal annealing is the same as that for temperature coefficient, implying the intense connection between compressive stress and thermal transport. Actually, 773 K thermal annealing can result in 2.02 GPa compressive stress on supported monolayer graphene due to the lattice mismatch of graphene and substrate. This study proposes thermal annealing as a feasible path to modulate the thermal transport in supported graphene and to design future graphene-based devices.

A step-feed anoxic/oxic/anoxic/oxic (SF-A/O/A/O) was developed and successfully applied to full-scale coking wastewater treatment. The performance and microbial community were evaluated and systematically compared with the anoxic/oxic/oxic (A/O/O) process. SF-A/OA/O process exhibited efficient removal of COD, NH4+-N, TN, phenols, and cyanide with corresponding average effluent concentrations of 317.9, 1.8, 46.2, 1.1, and 0.2 mg·L-1, respectively. In particular, the TN removal efficiency of A/O/O process was only 7.8%, with an effluent concentration of 300.6 mg·L-1. Furthermore, polycyclic aromatic hydrocarbons with high molecular weight were the dominant compounds in raw coking wastewater, which were degraded to a greater extent in SF-A/OA/O. The abundance in Thiobacillus, SM1A02, and Thauera could be the main reason why SF-A/O/A/O was superior to A/O/O in treating TN. The microbial community structure of SF-A/O/A/O was similar among stages in system (P ≥ 0.05, Welch's t-test) and was less affected by environmental factors, which may have been one of the important factors in the system's strong stability.

Low durability and fuel cell performance block the widespread application of polymer electrolyte fuel cells (PEFCs). Here, we deposit platinum nanoparticles on carbon nanotubes (CNTs) before coating by end-capped hyperbranched sulfonated macromolecules (E-HBM), which could provide sufficient proton conductivity in catalyst layer due to the presence of -SO3H groups. The fabricated electrocatalyst loses 43% of initial electrochemical surface area (ECSA) after 200,000 potential cycles from 1.0 V to 1.5 V vs. RHE, which is 3 and 20 times higher compared to non-coated and commercial electrocatalysts, respectively. The mass and specific activities of newly fabricated electrocatalyst measured before and after durability test are 1.4 times higher compared to commercial CB/Pt. Nafion ionomer-free membrane electrode assembly (MEA) is fabricated from the newly designed electrocatalyst and fuel cell performance reaches 668 mW cm-2 with Pt loading of 0.1 mg cm-2, which is twice higher than that of commercial CB/Pt due to the homogeneous conductive macromolecules (E-HBM) layers on CNTs acting as ionomer and facilitating the proton delivery in catalyst layer.

On-line chemical cleaning with sodium hypochlorite (NaClO) has been extensively practiced for maintaining the stable permeability of membrane bioreactor (MBR), during which activated sludge is inevitably exposed to NaClO. The authors previously reported the NaClO-induced generation of dissolved organic matter (DOM) and halogenated byproducts, however their fate in terms of biodegradability and removability in MBR has been unknown. Therefore, this study investigated the removal mechanisms of generated DOM and byproducts in an aerobic MBR. It was found that about 39% of DOM produced was removed through biodegradation and membrane rejection. The fluorescence excitation-emission matrix (EEM) coupled with parallel factor analysis (PARAFAC) also revealed that protein-like substances were more readily biodegradable than humic-like substances. Moreover, 25 kinds of chlorinated and brominated byproducts were detected after the contact of biomass with NaClO by ultra performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, while nine of which were confirmed with standard compounds. 62.4–84.5% halogenated byproducts were ended up in permeate of MBR chemically cleaned with 5–20 mg/L of NaClO. This study raises a serious concern on reusing and recycling of such MBR permeate.

Homogeneous ionomer networks are primarily important for the enhancement of fuel cell performance. Here, we report a bottom-up design of platinum (Pt) electrocatalysts with homogeneous ionomer layers, in which Pt nanoparticles are deposited on carbon nanotubes (CNTs) after sequentially wrapping with polybenzimidazole (PBI) and end-capped hyperbranched sulfonated macromolecules (E-HBM) (CNT/PBI/E-HBM/Pt). E-HBM, which are proton conductive macromolecules, are homogeneously coated on CNTs owing to the base–acid interaction between PBI and E-HBM. The durability and oxygen reduction reaction (ORR) results indicate that CNT/PBI/E-HBM/Pt exhibits higher Pt stability and ORR activity compared with the electrocatalyst without E-BHM. The Nafion ionomer-free membrane electrode assembly (MEA) fabricated from CNT/PBI/E-HBM/Pt (704 mW cm−2) shows higher power density than the MEA from CNT/PBI/Pt with Nafion ionomer (30 wt %, 603 mW cm−2) owing to the unique bottom-up design resulting in high Pt utilization efficiency.

Improvements on durability and CO tolerance of the electrocatalyst are crucial for widespread commercialization of direct methanol fuel cells (DMFCs). In this work, we describe a new method to stabilize the PtRu electrocatalyst, in which the PtRu nanoparticles are coated by nitrogen doped carbon layer derived from the carbonization of poly(vinyl pyrrolidone). The coated electrocatalyst shows stable electrochemical surface area (ECSA) and methanol oxidation reaction (MOR) activity after 4200 potential cycles from 0.6 V to 1.0 V vs . RHE; while the non-coated and commercial electrocatalyst lose almost 50% of initial ECSA and MOR activity. Meanwhile, the coated electrocatalyst shows twice higher CO tolerance before and after durability test due to the deceleration of the Ru dissolution proved by the XPS measurement after durability test. The mechanism of the stabilization of Ru was the electron delocalization of Ru caused by the carbonization process of PVP, which changes the electronic structure of Ru and makes Ru difficult to be dissolved. The maximum power density of the coated electrocatalyst is 1.7 times higher than that of commercial CB/PtRu, suggesting the coated electrocatalyst is suitable for real DMFC application. The demonstrated method could be easily extended to obtain extraordinary durability of other electrocatalysts.

In this work, we focus on the durability, CO tolerance and sluggish methanol oxidation reaction (MOR) of PtRu electrocatalyst. Here, we fabricate a new PtRu electrocatalyst supported on carbon black (CB), in which the PtRu nanoparticles are structurally sandwiched by poly(vinyl pyrrolidone) (PVP) and poly(2,5-benzimidazole) (ABPBI). Due to the first coating (PVP) on CB, the micropores on CB are capped resulting in high Pt utilization efficiency (94%) and catalytic activity toward methanol oxidation. Meanwhile, the second coating (ABPBI) on PtRu nanoparticles fabricated via in-situ polymerization improves the PtRu stability and decelerates the Ru dissolution leading to stable electrochemical surface area (ECSA), MOR activity and CO tolerance during the durability test. Without ABPBI coating, ECSA and catalytic activity remain only 50% after potential cycling. Additionally, the fuel cell performance of double polymer coated electrocatalyst reaches 103 mW cm−2, which is among the highest values reported in the recent literatures.

The effects of chemosynthetic and biological surfactants on accelerating hydrogen generation from waste activated sludge (WAS) is investigated in a short-cut fermentation-bioelectrochemical system. The specific experiments are conducted in a series of completely stirred tank reactors (CSTRs) and single-chamber microbial electrolysis cells (MECs). Results shows that rhamnolipid (RL) lead to a VFAs yield 1.16-fold and 3.63-fold higher over with sodium dodecylsulphate (SDS) and sodium dodecyl benzene sulfonate (SDBS) treatments in CSTRs on 72 h. By contrast, the corresponding conversion efficiency of methanogenesis is inhibited (0.18 ± 0.03% versus 1.89 ± 0.15% (SDS) and 6.63 ± 0.77% (SDBS)), which is beneficial for subsequent hydrogen production in MECs. The distribution of the acidogenesis metabolites is also affected by the types of surfactants, reflected on cascade changing of hydrogen production. Highest hydrogen yield is 12.90 mg H2 g−1 VSS in RL-MECs, which is larger than all values that have been reported for fermentation and single-chamber MECs. Current and electrochemical impedance spectroscopy clearly demonstrate the important role of RL treatment in electron/proton transfer and the internal resistance decrease. This study demonstrate the sustainability and attractiveness of WAS short-cut fermentation-elelctrohydrogenesis, providing a sound basis for sludge stabilization and bioenergy recovery.