Strategies for Sustainable Production of Hydrogen Peroxide via Oxygen Reduction Reaction: From Catalyst Design to Device Setup.

An environmentally benign, sustainable, and cost-effective supply of H2O2 as a rapidly expanding consumption raw material is highly desired for chemical industries, medical treatment, and household disinfection. The electrocatalytic production route via electrochemical oxygen reduction reaction (ORR) offers a sustainable avenue for the on-site production of H2O2 from O2 and H2O. The most crucial and innovative part of such technology lies in the availability of suitable electrocatalysts that promote two-electron (2e-) ORR. In recent years, tremendous progress has been achieved in designing efficient, robust, and cost-effective catalyst materials, including noble metals and their alloys, metal-free carbon-based materials, single-atom catalysts, and molecular catalysts. Meanwhile, innovative cell designs have significantly advanced electrochemical applications at the industrial level. This review summarizes fundamental basics and recent advances in H2O2 production via 2e--ORR, including catalyst design, mechanistic explorations, theoretical computations, experimental evaluations, and electrochemical cell designs. Perspectives on addressing remaining challenges are also presented with an emphasis on the large-scale synthesis of H2O2 via the electrochemical route.

Atomically Dispersed Manganese on Carbon Substrate for Aqueous and Aprotic CO2 Electrochemical Reduction.

CO2 utilization and conversion are of great importance in alleviating the rising CO2 concentration in the atmosphere. Here, a single-atom catalyst (SAC) is reported for electrochemical CO2 utilization in both aqueous and aprotic electrolytes. Specifically, atomically dispersed Mn-N4 sites are embedded in bowl-like mesoporous carbon particles with the functionalization of epoxy groups in the second coordination spheres. Theoretical calculations suggest that the epoxy groups near the Mn-N4 site adjust the electronic structure of the catalyst with reduced reaction energy barriers for the electrocatalytic reduction of CO2 to CO. The resultant Mn-single-atom carbon with N and O doped catalyst (MCs-(N,O)) exhibits extraordinary electrocatalytic performance with a high CO faradaic efficiency of 94.5%, a high CO current density of 13.7 mA cm-2 , and a low overpotential of 0.44 V in the aqueous environment. Meanwhile, as a cathode catalyst for aprotic Li-CO2 batteries, the MCs-(N,O) with well-regulated active sites and unique mesoporous bowl-like morphology optimizes the nucleation behavior of discharge products. MCs-(N,O)-based batteries deliver a low overpotential and excellent cyclic stability of 1000 h. The findings in this work provide a new avenue to design and fabricate SACs for various electrochemical CO2 utilization systems.

Edge-hosted Atomic Co-N4 Sites on Hierarchical Porous Carbon for Highly Selective Two-electron Oxygen Reduction Reaction.

Not only high efficiency but also high selectivity of the electrocatalysts is crucial for high-performance, low-cost, and sustainable energy storage applications. Herein, we systematically investigate the edge effect of carbon-supported single-atom catalysts (SACs) on oxygen reduction reaction (ORR) pathways (two-electron (2 e- ) or four-electron (4 e- )) and conclude that the 2 e- -ORR proceeding over the edge-hosted atomic Co-N4 sites is more favorable than the basal-plane-hosted ones. As such, we have successfully synthesized and tuned Co-SACs with different edge-to-bulk ratios. The as-prepared edge-rich Co-N/HPC catalyst exhibits excellent 2 e- -ORR performance with a remarkable selectivity of ≈95 % in a wide potential range. Furthermore, we also find that oxygen functional groups could saturate the graphitic carbon edges under the ORR operation and further promote electrocatalytic performance. These findings on the structure-property relationship in SACs offer a promising direction for large-scale and low-cost electrochemical H2 O2 production via the 2 e- -ORR.

Evolving aprotic Li-air batteries.

Lithium-air batteries (LABs) have attracted tremendous attention since the proposal of the LAB concept in 1996 because LABs have a super high theoretical/practical specific energy and an infinite supply of redox-active materials, and are environment-friendly. However, due to the lack of critical electrode materials and a thorough understanding of the chemistry of LABs, the development of LABs entered a germination period before 2010, when LABs research mainly focused on the development of air cathodes and carbonate-based electrolytes. In the growing period, i.e., from 2010 to the present, the investigation focused more on systematic electrode design, fabrication, and modification, as well as the comprehensive selection of electrolyte components. Nevertheless, over the past 25 years, the development of LABs has been full of retrospective steps and breakthroughs. In this review, the evolution of LABs is illustrated along with the constantly emerging design, fabrication, modification, and optimization strategies. At the end, perspectives and strategies are put forward for the development of future LABs and even other metal-air batteries.

Cyclohexanedodecol-Assisted Interfacial Engineering for Robust and High-Performance Zinc Metal Anode.

Aqueous zinc-ion batteries (AZIBs) can be one of the most promising electrochemical energy storage devices for being non-flammable, low-cost, and sustainable. However, the challenges of AZIBs, including dendrite growth, hydrogen evolution, corrosion, and passivation of zinc anode during charging and discharging processes, must be overcome to achieve high cycling performance and stability in practical applications. In this work, we utilize a dual-functional organic additive cyclohexanedodecol (CHD) to firstly establish [Zn(H2O)5(CHD)]2+ complex ion in an aqueous Zn electrolyte and secondly build a robust protection layer on the Zn surface to overcome these dilemmas. Systematic experiments and theoretical calculations are carried out to interpret the working mechanism of CHD. At a very low concentration of 0.1 mg mL-1 CHD, long-term reversible Zn plating/stripping could be achieved up to 2200 h at 2 mA cm-2, 1000 h at 5 mA cm-2, and 650 h at 10 mA cm-2 at the fixed capacity of 1 mAh cm-2. When matched with V2O5 cathode, the resultant AZIBs full cell with the CHD-modified electrolyte presents a high capacity of 175 mAh g-1 with the capacity retention of 92% after 2000 cycles under 2 A g-1. Such a performance could enable the commercialization of AZIBs for applications in grid energy storage and industrial energy storage.

Atomically Thin Materials for Next-Generation Rechargeable Batteries.

Atomically thin materials (ATMs) with thicknesses in the atomic scale (typically <5 nm) offer inherent advantages of large specific surface areas, proper crystal lattice distortion, abundant surface dangling bonds, and strong in-plane chemical bonds, making them ideal 2D platforms to construct high-performance electrode materials for rechargeable metal-ion batteries, metal-sulfur batteries, and metal-air batteries. This work reviews the synthesis and electronic property tuning of state-of-the-art ATMs, including graphene and graphene derivatives (GE/GO/rGO), graphitic carbon nitride (g-C3N4), phosphorene, covalent organic frameworks (COFs), layered transition metal dichalcogenides (TMDs), transition metal carbides, carbonitrides, and nitrides (MXenes), transition metal oxides (TMOs), and metal-organic frameworks (MOFs) for constructing next-generation high-energy-density and high-power-density rechargeable batteries to meet the needs of the rapid developments in portable electronics, electric vehicles, and smart electricity grids. We also present our viewpoints on future challenges and opportunities of constructing efficient ATMs for next-generation rechargeable batteries.

Robust Pseudocapacitive Sodium Cation Intercalation Induced by Cobalt Vacancies at Atomically Thin Co1-x Se2 /Graphene Heterostructure for Sodium-Ion Batteries.

Electronic structure engineering on electrode materials could bring in a new mechanism to achieve high energy and high power densities in sodium ion batteries. Herein, we design and create Co vacancies at the interface of atomically thin CoSe2 /graphene heterostructure and obtain Co1-x Se2 /graphene heterostructure electrode materials that facilitate significant Na+ intercalation pseudocapacitance. Density functional theory (DFT) calculation suggests that the Na+ adsorption energy is dramatically increased, and the Na+ diffusion barrier is remarkably reduced due to the introduction of Co vacancy. The optimized electrode delivers a superior capacity of 673.6 mAh g-1 at 0.1 C, excellent rate capability of 576.5 mAh g-1 at 2.0 C and ultra-long life up to 2000 cycles. Kinetics analysis indicates that the enhanced Na+ storage is mainly attributed to the intercalation pseudocapacitance induced by Co vacancies. This work suggests that the creation of cation vacancy could bestow heterostructured electrode materials with pseudocapacitive Na+ intercalation for high-capacity and high-rate energy storage.

Cu Nanoclusters/FeN4 Amorphous Composites with Dual Active Sites in N-Doped Graphene for High-Performance Zn-Air Batteries.

Exploring inexpensive and earth-abundant transition metal-nitrogen-based carbon (MNC) catalysts to substitute the scarce and costly Pt-based electrocatalysts for the oxygen reduction reaction (ORR) is quite anticipated in metal-air batteries (MABs). Here, we demonstrate a facile vacuum-annealing method to synthesize Cu nanoclusters/FeN4 amorphous composites embedded in N-doped graphene (Cu/Fe-NG). This approach avoids the long-term pyrolysis procedure and the use of an inert atmosphere in the conventional procedure for fabricating MNC catalysts. Interestingly, we discovered that the amorphous structure of Cu/FeN4 composites can provide high-activity bimetallic M-Nx sites (M = Cu, Fe), because of which the Cu/FeN4 composites exhibit boosted electrocatalytic activity with a positive half-wave potential of 0.88 V (vs RHE), long-term durability, and low hydrogen peroxide for the ORR. The origin of this enhancement was assigned to the concomitance of Fe-N4 and Cu-Nx moieties in Cu/Fe-NG, favoring adsorption and activation of the O2 molecule as suggested by X-ray absorption fine structure (XAFS) analyses and density functional theory (DFT) calculations. Moreover, examinations of Cu/Fe-NG in both liquid and quasi-solid-state Zn-air batteries (ZABs) can exhibit remarkable performances. This work may offer facile fabrication of enhanced performance MNC catalysts as well as a profound insight into the use of amorphous materials in the ORR and ZABs.

Interface Engineering of CoS/CoO@N-Doped Graphene Nanocomposite for High-Performance Rechargeable Zn-Air Batteries.

Low cost and green fabrication of high-performance electrocatalysts with earth-abundant resources for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are crucial for the large-scale application of rechargeable Zn-air batteries (ZABs). In this work, our density functional theory calculations on the electrocatalyst suggest that the rational construction of interfacial structure can induce local charge redistribution, improve the electronic conductivity and enhance the catalyst stability. In order to realize such a structure, we spatially immobilize heterogeneous CoS/CoO nanocrystals onto N-doped graphene to synthesize a bifunctional electrocatalyst (CoS/CoO@NGNs). The optimization of the composition, interfacial structure and conductivity of the electrocatalyst is conducted to achieve bifunctional catalytic activity and deliver outstanding efficiency and stability for both ORR and OER. The aqueous ZAB with the as-prepared CoS/CoO@NGNs cathode displays a high maximum power density of 137.8 mW cm-2, a specific capacity of 723.9 mAh g-1 and excellent cycling stability (continuous operating for 100 h) with a high round-trip efficiency. In addition, the assembled quasi-solid-state ZAB also exhibits outstanding mechanical flexibility besides high battery performances, showing great potential for applications in flexible and wearable electronic devices.

Genomic characterization of a novel recombinant porcine astrovirus isolated in northeastern China.

Porcine astroviruses (PAstVs), are widely distributed viruses that are highly prevalent in swine herds. In this study, a novel type 4 porcine astrovirus strain (designated as PAstV4/Tianjin/2018) was identified in a fecal sample from a diarrheal piglet in Tianjin, China and its complete genomic sequence was determined by RT-PCR. Sequence analysis showed that this strain had a capsid protein with a highly variable C-terminal domain, a typical ribosomal frameshifting signal, and a conserved subgenomic promoter sequence. Recombination analysis indicated that PAstV4/Tianjin/2018 was a novel recombinant strain, and a recombination breakpoint was identified at nt position 4220 of the genome. The novel recombinant porcine astrovirus identified in China will be useful for understanding the origin, genetic diversity, and evolution of enteric viruses.

A sensitive signal-on photoelectrochemical sensor for tetracycline determination using visible-light-driven flower-like CN/BiOBr composites.

As a broad-spectrum antibiotic, tetracycline (TC) is widely used in agricultural purposes and human therapy. More attention is paid to TC as a serious threat to human health, including the fast spreading of antibiotic resistance gene and the serious toxicity to aquatic organisms. Therefore, the timely and accurate determination of TC residues is an urgent task to protect the safety of human. Herein, an effective and facile photoelectrochemical sensor platform based on carbon nitride/bismuth oxyhalide (CN/BiOBr) composites can be constructed for monitoring TC. The flower-like CN/BiOBr composites are prepared via a simple one-pot ethylene glycol-assisted solvothermal process with the addition of ionic liquid 1-hexadecyl-3-methylimidazolium bromide ([C16mim]Br). In view of matched energy band positions of CN and BiOBr, the addition of CN can reduce the recombination of photogenerated electron-hole pairs and improve the efficiency of visible light utilization, leading to enhancing photoelectrochemical response of BiOBr. Under light excitation, the photocurrent of CN/BiOBr composites is drastically improved, which is 6 times as much as that of pure BiOBr. Considering the superior photoelectrochemical performance, a photoelectrochemical sensor for monitoring TC has been developed, displaying linearly enhanced photocurrent with increasing the TC concentration. Two linear relationships received are from 8.0 to 4.0 × 102 ng mL-1, and 4.0 × 102 to 5.2 × 103 ng mL-1, respectively. The detection limit is 3.8 ng mL-1. The photoelectrochemical sensor exhibits a series of benefits including excellent stability, a wide linear range, a low detection limit and good anti-interference ability. Therefore, this work may offer great promises in providing a universal and efficient photoelectrochemical sensor for the tetracycline detection, and pave the way of constructing more materials used in photoelectrochemical detection field.

Anti-proliferative effect of Flos Albiziae flavonoids on the human gastric cancer SGC-7901 cell line.

The flavonoids found in many foods may have a protective effect against human gastric cancer. However, little information is available concerning the effects of flavonoids on the SGC-7901 cell line. Therefore, we first evaluated the effects of purified Flos Albiziae flavonoids (FAFs) on the proliferation of the SGC-7901 human gastric cancer cell line and investigated its possible anti-proliferative mechanisms. When SGC-7901 cells were treated with FAFs for various time periods (12-72 h) and at various doses (0-32 µg/ml), cell growth decreased significantly in a time- and dose-dependent manner. Morphological observations with fluorescence microscopy and transmission electron microscopy (TEM) yielded clear evidence of cell shrinkage, formation of cytoplasmic filaments, condensation of nuclear chromatin, and cell apoptosis in the presence of FAFs. Treatment with FAFs changed the expression levels of Bcl-2, P65, Bax and caspase. The anti-apoptotic protein expression of Bcl-2 and p65 decreased gradually with the increase in FAF concentration, compared with control cells (P<0.05). FAFs contributed to the increase in Bax and caspase expression. The expression of pro-apoptotic proteins Bax and caspase were upregulated by FAFs compared with control cells (P<0.01). These results demonstrated that FAFs effectively induced apoptosis in the SGC-7901 cell line. This indicates that FAFs are likely to possess anticancer activity.

Relationship between BMD and Zn, Cu, Ca levels in the hair and meal in elderly people.

The relationship between bone mineral density (BMD) and Zn, Cu, Ca levels in the meal and hair of urban and rural elderly people were studied. 470 subjects above 60 years old (urban 205 and rural 265), 178 males with an average age of 65.70 +/- 3.48 and 292 females with an average age of 65.90 +/- 4.02, were inquired. The BMD and Zn, Cu, Ca levels in the meal and hair were measured. The detected BMD in urban and rural female old people was significantly lower than that of the males; The contents of Ca and Zn in the meal of the urban females were significantly lower than those of the urban males; The Ca, Zn in the meal and Zn in the hair of the rural females were significantly lower than those of rural males (P < 0.05 or 0.01). The BMD, Ca intakes, Ca and Zn in the hair of the rural old people were significantly lower than those of the urban old people (P < 0.05 or 0.01). There was a correlation between BMD with the Ca, Zn of the hair and dietary Ca, Zn, Cu or between dietary Zn with Ca, Zn in the hair and Ca, Cu intakes. The Zn, Cu and Ca levels in the meal nutrients were correlated with BMD to some degrees. Lack of Ca and Zn in the meal can cause the reduction of BMD.

[Effects of taurine on the heart defects in chick embryos which induced by homocysteine].

OBJECTIVE: To explore the effects of taurine on the heart defects in chick embryos induced by homocysteine (HCY). METHODS: Through the teratogenicity test of Chick Embryos, the taurine and HCY were given to yolk sac of 3 day's chick embryos. Histopathological examination after another 2 days culture. RESULTS: The occurrence of heart defects on HCY group were significantly increased. The growth of vitelline vessels was decreased. The prevention of tautine on the heart defects in chick embryos induced by HCY was very significantly effective. CONCLUSION: Taurine can prevent the developmental disturbance of hearts induced by HCY in this experiment.

[Effects of soybean isoflavone and calcium on proliferation, differentiation and mineralization of cultured osteoblasts in vitro].

To explore the effects of soybean isoflavone and calcium on proliferation, differentiation and mineralization of cultured osteoblastic cells. Osteoblastic cells from newborn rat calvarial was cultured. Osteoblastic cells proliferation was measured by MTT, activity of APL was observed with Golden's method and ARS was used to measure the mineral nodes of osteoblasts. The results showed that the calcium group had not different from the control group on stimulating the proliferation, differentiation and mineralization of rat calvarial osteoblastic cells. The soybean isoflavone group had significant effects on stimulating the proliferation, differentiation of osteoblasts and increase the forming of the mineral nodes of osteoblasts in rat. Calcium and soybean isoflavone group had more benefit for forming mineral nodes. The soybean isoflavone stimulates the proliferation, differentiation and mineralization of rat calvarial osteoblastic cells, and increase calcium in the same time is more benefit for mineralization.

[Effect of calcium supplement on superoxide dismutase and malonaldehyde of disuse osteoporosis in young rats].

Effects of Ca supplement on the bone mineral density(BMD), red blood cell superoxide dismutase(SOD), plasma malonaldehyde(MDA) of disused osteoporosis were studied in this paper. Twenty five healthy pregnant SD rats were randomly divided into 5 groups, groups 2-5 were reproduced with patterns of animal osteoporosis. The diet in groups 1-2 was the basic diet, while the groups 3-5 experiment diets were supplemented with Ca. Selected 3 young rats, live with the mother rate each brood. The BMD, red blood cell SOD, plasma MDA were measured 37 d later. The results showed that BMD level of young rats in Ca supplement groups is higher than vigorous groups (P < 0.05). The MDA in vigorous group was higher than Ca supplement, groups(P < 0.01) and SOD was lower than high biologic calcium group(P < 0.05). It was suggested that Ca supplemented certain effect on red blood cell SOD, plasma MDA of disused osteoporosis.