Optimizing Li2O-2B2O3 coating layer on LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material for high-performance lithium-ion batteries

ABSTRACT

In this paper, a wet chemical method is used to coat LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode material by Li₂O-2B₂O₃ (LBO) layer for Lithium-ion batteries (LIBs). For performance optimization, the effects of different contents (thicknesses) of LBO coating layers on NCM811 particle surface on the morphologies, structures, compositions, and electrochemical properties of the corresponding LIBs are studied using XRD, SEM, TEM, and electrochemical measurements. Coin LIBs are assembled with such coated NCM811 cathode materials for performance validation. Results show that LBO coating layer does not change the original lattice structure of the bulk material, it can only adhere to the surface of the bulk material. After coating, NCM811 shows a good crystallinity and the ordered layered structure. TEM images show that the thickness of LBO coating is increased with increasing LBO content, and that the appropriate LBO coating thickness and uniform coating state are conducive to the improvement of the electrochemical properties of NCM811 cathode materials. Particularly, NCM811 with LBO coating content of 1000 ppm shows the best performance compared to other coating contents. In this case, the coating thickness is relatively uniform, which is about 40～100 nm, giving a good first charge-discharge capacity of 214.1mAh/g, and a high Coulomb efficiency of 90.06%. After 50 cycles, the capacity retention rate of LIBs still keeps as high as 99.64%. Therefore, LBO coating can improve the performance of NCM811 and then the lithium-ion batteries.     

Detecting the Dynamic Linkage between Landscape Characteristics and Water Quality in a Subtropical Coastal Watershed, Southeast China

Geospatial analysis and statistical analysis are coupled in this study to determine the dynamic linkage between landscape characteristics and water quality for the years 1996, 2002, and 2007 in a subtropical coastal watershed of Southeast China. The landscape characteristics include Percent of Built (%BL), Percent of Agriculture, Percent of Natural, Patch Density and Shannon’s Diversity Index (SHDI), with water quality expressed in terms of COD_Mn and NH₄ ⁺–N. The %BL was consistently positively correlated with NH₄ ⁺–N and COD_Mn at time three points. SHDI is significantly positively correlated with COD_Mn in 2002. The relationship between NH₄ ⁺–N, COD_Mn and landscape variables in the wet precipitation year 2007 is stronger, with R² = 0.892, than that in the dry precipitation years 1996 and 2002, which had R² values of 0.712 and 0.455, respectively. Two empirical regression models constructed in this study proved more suitable for predicting COD_Mn than for predicting NH₄ ⁺–N concentration in the unmonitored watersheds that do not have wastewater treatment plants. The calibrated regression equations have a better predictive ability over space within the wet precipitation year of 2007 than over time during the dry precipitation years from 1996 to 2002. Results show clearly that climatic variability influences the linkage of water quality-landscape characteristics and the fit of empirical regression models.     

Design and optimization of new La1−xCexNi1−yFeyO3 (x,y = 0–0.4) nano catalysts in dry reforming of methane

The paper reports the production of syngas from dry reforming of methane (DRM) over La_1?xCe_xNi_1?yFe_yO₃ (x, y = 0–0.4) perovskites. A series of La_1?xCe_xNi_1?yFe_yO₃ were designed by central composite design (CCD) and synthesized by a sol–gel auto combustion method. Artificial neural network (ANN) approach was used to determine the relationship between preparation and operational parameters on the performance of the catalysts in the DRM process. Nickel mole fraction, lanthanum mole fraction, calcination temperature, and reaction temperature were considered as input variables, and conversion of methane was considered as the output variable. An ANN model with nine neurons in the hidden layer was the suitable in predicting conversion of methane. The genetic algorithm (GA) was subsequently used to determine the optimal preparation condition for enhancing the conversion of methane. La_0.6Ce_0.4Ni_0.99Fe_0.01O₃ catalyst, calcined at 756°C was obtained to be the most active catalyst owing to the optimal composition of nickel and lanthanum in the catalyst formulation.     

Effect of Fenton pretreatment on anaerobic digestion of olive mill wastewater and olive mill solid waste in mesophilic conditions

The olive mill waste (OMW) generated from olive oil extraction process constitutes a major environmental concern owing to its high organic and mineral matters and acidic pH. Anaerobic digestion (AD) is a main treatment for reducing the organic matter and toxic substances contained in OMW and generating at the same time, energy in the form of biogas. AD of OMW that contains lignocellulose is limited by the rate of hydrolysis due to their recalcitrant structure. This study is devoted to the effect of Fenton process (FP) pretreatment on olive mill wastewater (OMSW) /olive mill solid waste (OMWW) co-digestion to improve their digestibility and in this way the biogas production. The FP pretreatment was performed in batch mode at 25°C, various H₂O₂/[Fe²⁺] ratios (100–1200), catalyst concentration ([Fe²⁺]) ranging from 0.25 to 2 mM, reaction time varying from 30 to150 min, and different pH (3–11). The best performance was obtained with H₂O₂/[Fe²⁺] = 1000, [Fe²⁺] = 1.5 mM, 120 min, and pH 3. Biochemical methane potential (BMP) tests conducted in batch wise digester and at mesophilic conditions (37 °C) showed that cumulative biogas and methane production were higher without FP treatment, and correspond to 699 and 416 mL/g VS, respectively. However, pre-treated OMSW results into an increase of 24% of methane yield. After 30 days of AD, the methane yield was 63%, 54%, and 48%, respectively, for OMSW treated without iron precipitation, with iron precipitation and untreated OMSW sample.     

Performance investigation of a single-stage metal hydride heat transformer

This article presents the performance analysis of a single-stage metal hydride-based heat transformer (SS-MHHT) working with three different alloy pairs, namely LaNi_4.6Al_0.4/MmNi_4.15Fe_0.85, LaNi_4.61Mn_0.26Al_0.13/La_0.6Y_0.4Ni_4.8-Mn_0.2, and Zr_0.9Ti_0.1Cr_0.9Fe_1.1/Zr_0.9Ti_0.1Cr_0.6-Fe_1.4. The performances of the SS-MHHT are predicted by solving the conjugate heat and mass (hydrogen) transfer equations in cylindrical coordinates. The effects of various parameters such as heat output (T_H), heat input (T_M), and heat sink (T_L) temperatures on the coefficient of performance (COP_HT), specific heating power (SHP) and second law efficiency (η_E) are presented. The effects of overall heat transfer coefficient and mass ratio on the coefficient of performance (COP_HT) and specific heating power (SHP) are also presented. Numerical results are compared with the experimental data reported in the literature, and a good agreement is found between them. The maximum COP_HT of 0.436 and SHP of 54 W/kg are obtained for LaNi_4.61Mn_0.26Al_0.13/La_0.6Y_0.4Ni_4.8-Mn_0.2 pair. For a given operating temperatures of T_M = 358 K and T_L = 298 K, the maximum temperature lift of about 50 K is predicted for Zr_0.9Ti_0.1Cr_0.9Fe_1.1 /Zr_0.9Ti_0.1Cr_0.6Fe_1.4 pair.     

Assessment of biomass and lipid productivity and biodiesel quality of an indigenous microalga Chlorella sorokiniana MIC-G5

Generation of biodiesel from microalgae has been extensively investigated; however, its quality is often not suitable for use as fuel. Our investigation involved the evaluation of biodiesel quality using a native isolate Chlorella sorokiniana MIC-G5, as specified by American Society for Testing and Materials (ASTM), after transesterification of lipids with methanol, in the presence of sodium methoxide. Total quantity of lipids extracted from dry biomass, of approximately 410–450 mg g^?1 was characterized using FTIR and ¹H NMR. After transesterification, the total saturated and unsaturated fatty acid methyl esters (FAMEs) were 43% and 57%, respectively. The major FAMEs present in the biodiesel were methyl palmitate (C16:0), methyl oleate (C18:1), and methyl linoleate (C18:2), and the ¹H NMR spectra matched with criteria prescribed for high-quality biodiesel. The biodiesel exhibited a density of 0.873 g cm^–3, viscosity of 3.418 mm² s^?1, cetane number (CN) of 57.85, high heating value (HHV) of 40.25, iodine value of 71.823 g I₂ 100 g^?1, degree of unsaturation (DU) of 58%, and a cold filter plugging point (CFPP) of –5.22°C. Critical fuel parameters, including oxidation stability, CN, HHV, iodine value, flash point, cloud point, pour point, density, and viscosity were in accordance with the methyl ester composition and structural configuration. Hence, C. sorokiniana can be a promising feedstock for biodiesel generation.     

A nanocomposite of CoFe2O4-carbon microspheres for electrochemical energy storage applications

A carbon/CoFe₂O₄ composite was synthesized by precipitation method. The morphology of the composite was analyzed using scanning electron microscopy, X-ray diffraction, transmission electron microscopy, Fourier Transform Infrared Spectra, and vibrating sample magnetometry. The electrocapacitive behaviors of the composite has been studies by cycle voltammogram and galvanic charge/discharge. The size of the nanoparticles carbon composite of CoFe₂O₄ was uniform and 209 nm. Due to a high percent of carbon, electrochemical measurements showed electrical double layer mechanism. Specifically, the carbon/cobalt ferrite electrode exhibited high specific capacitance of 102.5 F g^?1 at a current density of 0.16 A g^?1, and high rate capability with 30% retention of capacitance even up to 20 A g^?1, and excellent cycling stability with 81.5% retention of the initial capacitance after 6000 charge/discharge cycles, supporting that the carbon cobalt ferrite composite electrode could be a potential candidate for supercapacitor application.     

Net Carbon Sequestration Potential and Emissions in Home Lawn Turfgrasses of the United States

Soil analyses were conducted on home lawns across diverse ecoregions of the U.S. to determine the soil organic carbon (SOC) sink capacity of turfgrass soils. Establishment of lawns sequestered SOC over time. Due to variations in ecoregions, sequestration rates varied among sites from 0.9 Mg carbon (C) ha^?1 year^?1 to 5.4 Mg C ha^?1 year^?1. Potential SOC sink capacity also varied among sites ranging from 20.8 ± 1.0–96.3 ± 6.0 Mg C ha^?1. Average sequestration rate and sink capacity for all sites sampled were 2.8 ± 0.3 Mg C ha^?1 year^?1 and 45.8 ± 3.5 Mg C ha^?1, respectively. Additionally, the hidden carbon costs (HCC) due to lawn mowing (189.7 kg Ce (carbon equivalent) ha^?1 year^?1) and fertilizer use (63.6 kg Ce ha^?1 year^?1) for all sites totaled 254.3 kg Ce ha^?1 year^?1. Considering home lawn SOC sink capacity and HCC, mean home lawn sequestration was completely negated 184 years post establishment. The potential SOC sink capacity of home lawns in the U.S. was estimated at 496.3 Tg C, with HCC of between 2,504.1 Gg Ce year^?1 under low management regimes and 7551.4 Gg Ce year^?1 under high management. This leads to a carbon-positive system for between 66 and 199 years in U.S. home lawns. More efficient and reduction of C-intensive maintenance practices could increase the overall sequestration longevity of home lawns and improve their climate change mitigation potential.     

Evaluation of Fenton and ozone-based advanced oxidation processes as mature landfill leachate pre-treatments

Fenton treatment (Fe²⁺/H₂O₂) and different ozone-based Advanced Oxidation Processes (AOPs) (O₃, O₃/OH⁻ and O₃/H₂O₂) were evaluated as pre-treatment of a mature landfill leachate, in order to improve the biodegradability of its recalcitrant organic matter for subsequent biological treatment. With a two-fold diluted leachate, at optimised experimental conditions (initial pH 3, H₂O₂ to Fe²⁺ molar ratio of 3, Fe²⁺ dosage of 4 mmol L⁻¹, and reaction time of 40 min) Fenton treatment removed about 46% of chemical oxygen demand (COD) and increased the five-day biochemical oxygen demand (BOD₅) to COD ratio (BOD₅/COD) from 0.01 to 0.15. The highest removal efficiency and biodegradability was achieved by ozone at higher pH values, solely or combined with H₂O₂. These results confirm the enhanced production of hydroxyl radical under such conditions. After the application for 60 min of ozone at 5.6 g O₃ h⁻¹, initial pH 7, and 400 mg L⁻¹ of hydrogen peroxide, COD removal efficiency was 72% and BOD₅/COD increased from 0.01 to 0.24. An estimation of the operating costs of the AOPs processes investigated revealed that Fe²⁺/H₂O₂ was the most economical system (8.2 € m⁻³ g⁻¹ of COD removed) to treat the landfill leachate. This economic study, however, should be treated with caution since it does not consider the initial investment, prices at plant scale, maintenance and labour costs.     

Modification Effect of Proton-Exchange Membrane on Methanol Permeation and Proton Conductivity for Direct Methanol Fuel Cell

Abstract

The Nafion membranes modified with a long chain counter ion, (C₈H₁₇)₄N⁺ or (CH₃)₄N⁺, and sandwich-type modified Nafion membranes were prepared as proton conducting membranes (PEM) for a direct methanol fuel cell (DMFC). We evaluated the methanol permeability, ionic conductivity, ion cluster diameter, ion exchange capacity and water content. The ion cluster diameter of the modified Nafion membranes was determined by small angle X-ray diffraction (SAXRD) measurements, and decreased in comparison with Nafion 117. The methanol crossover flux decreased to less than 10% that of Nafion 117 with the decreasing ion cluster diameter. For the sandwich-type membrane (Octyl-s1), the methanol crossover flux was 46% that of Nafion 117 and the ionic conductivity was 4.2 S/m.     

Effect of Prescribed Fire on Soil Properties and N Transformation in Two Vegetation Types in South China

Prescribed fire is a common site preparation practice in forest management in southern China. However, the effect of fire on soil properties and N transformations is still poorly understood in this region. In this study, soil properties and N transformations in burned and unburned site of two vegetation types (Eucalyptus plantation and shrubland) were compared in rainy and dry seasons after 2 years’ prescribed fire. Soil pH and soil NH₄-N were all higher in the burned site compared to the unburned control. Furthermore, burned sites had 30–40 % lower of soil total phosphorus than conspecific unburned sites. There was no difference in soil organic matter, total N, soil exchangeable cations, available P or NO₃-N. Nitrogen mineralization rate of 0–5 cm soil in the unburned site ranged from 8.24 to 11.6 mg N kg^?1 soil month^?1 in the rainy season, compared to a lower level of 4.82–5.25 mg N kg^?1 soil month^?1 in the burned sites. In contrast, 0–5 cm layer nitrification rate was overall 2.47 mg N kg^?1 soil month^?1 in the rainy season, and was not significantly affected by burning. The reduced understory vegetation coverage after burning may be responsible for the higher soil NH₄-N in the burned site. This study highlights that a better understanding the effect of prescribed burning on soil nutrients cycling would provide a critical foundation for management decision and be beneficial to afforestation in southern China.     

Defining Nutrient and Biochemical Oxygen Demand Baselines for Tropical Rivers and Streams in São Paulo State (Brazil): A Comparison Between Reference and Impacted Sites

Determining reference concentrations in rivers and streams is an important tool for environmental management. Reference conditions for eutrophication-related water variables are unavailable for Brazilian freshwaters. We aimed to establish reference baselines for São Paulo State tropical rivers and streams for total phosphorus (TP) and nitrogen (TN), nitrogen-ammonia (NH₄ ⁺) and Biochemical Oxygen Demand (BOD) through the best professional judgment and the trisection methods. Data from 319 sites monitored by the São Paulo State Environmental Company (2005 to 2009) and from the 22 Water Resources Management Units in São Paulo State were assessed (N = 27,131). We verified that data from different management units dominated by similar land cover could be analyzed together (Analysis of Variance, P = 0.504). Cumulative frequency diagrams showed that industrialized management units were characterized by the worst water quality (e.g. average TP of 0.51 mg/L), followed by agricultural watersheds. TN and NH₄ ⁺ were associated with urban percentages and population density (Spearman Rank Correlation Test, P < 0.05). Best professional judgment and trisection (median of lower third of all sites) methods for determining reference concentrations showed agreement: 0.03 &; 0.04 mg/L (TP), 0.31 &; 0.34 mg/L (TN), 0.06 &; 0.10 mg-N/L (NH₄ ⁺) and 2 &; 2 mg/L (BOD), respectively. Our reference concentrations were similar to TP and TN reference values proposed for temperate water bodies. These baselines can help with water management in São Paulo State, as well as providing some of the first such information for tropical ecosystems.     

Transesterification of Pistacia chinensis seed oil using a porous cellulose-based magnetic heterogeneous catalyst

In the present work, a novel cellulose-based porous heterogeneous solid acid catalyst encapsulation of ferriferous oxide (Fe₃O₄) and sulfonated graphene (GO-SO₃H) into cellulose to form composite porous microspheres catalyst (GO-SO₃H/CM@Fe₃O₄)was synthesized and evaluated for biodiesel production from Pistacia chinensis seed oil. The SEM, EDS and FTIR analysis revealed that the catalyst GO-SO₃H/CM@Fe₃O₄ owned stronger active sites and GO-SO₃H dispersed well in porous surface and inside of cellulose support. Under the optimum conditions, microwave-assisted transesterification process was carried out with the best catalyst amount, i.e. 5 wt% GO-SO₃H/CM@Fe₃O₄ (weight ratio of GO-SO₃H/cellulose), and conversion yield reached 94%. The prepared catalyst could be easily separated from reaction solution by extra magnetic field and reclaimed at least five runs.     

A study on oxidative degradation of polyacrylamide in wastewater with UV/FENTON/C4H4O62−

The degradation of polyacrylamide (PAM) in simulate wastewater was studied in UV/Fenton/C₄H₄O₆^2? system. The factors such as molecular ratio of H₂O₂/Fe²⁺/C₄H₄O₆^2?, pH, and the dosage of Fenton reagent that could affect the PAM degradation in the UV/Fenton/C₄H₄O₆^2? system were investigated. The experimental results showed that adding C₄H₄O₆^2? to UV/Fenton system could form photosensitive ferrous complexes, which led to higher degradation efficiency of PAM. The degradation rate of PAM could be up to 95.2% under the following conditions: the concentration of H₂O₂, Fe²⁺, and C₄H₄O₆^2? were 22.5, 2.25, and 2.25 mmol/L, respectively (i.e., molecular ratio of H₂O₂/Fe²⁺/C₄H₄O₆^2? was 10:1:1), the pH value was 3.0.     

The metabolic pathway of 4?Hz mechanical vibration-induced effect on snail heart muscle contractility

It was shown that the 4 Hz 30 dB mechanical vibration (MV) of physiological solution (PS) had modulation effect on snail heart contractility. However, the nature of metabolic pathway of MV-treated PS-induced effect is not clear yet. It was suggested that the MV-induced modulation of water molecules dissociation leads to the variation of reactive oxygen species’ level in cell bathing medium, which could serve as a messenger for switching on the metabolic pathway(s) responsible for modulation of muscle contractility. The aim of present work was to check this hypothesis and to elucidate the metabolic pathway through which the effect of MV-treated PS on heart contractility was realized. For this purpose, the effect of MV on heat fusion periods (HFP) and H₂O₂ content in PS, as well as on heart contractility, ⁴⁵Ca²⁺ efflux, intracellular levels of cGMP and cAMP, muscle hydration, and ouabain binding were studied. It was shown that MV treatment of PS increased the HFP-(21.33 ± 4%) and decreased the H₂O₂ content-(5 ± 0.9%). The intracardiac perfusion by MV-treated PS increased the amplitudes of heart contractility, which was accompanied by the increasing of ⁴⁵Ca²⁺ efflux (252.4 ± 16%), elevation of cGMP’s level (42.05 ± 7%), decreasing of cAMP’s level (82.67 ± 7%), increasing of the tissue hydration (18.64 ± 3%), and increasing of the number of ouabain binding sides (25 ± 4%). It was suggested that MV-induced increasing of heart muscle contraction amplitudes is due to the decreases of H₂O₂ content in the medium, which leads to the elevation of heart muscle contractility in result of activation of cGMP-dependent Na⁺/Ca²⁺ exchange in forward regime.     

Numerical parametric study on CO2 capture by indirect thermal swing adsorption

Post-combustion CO₂ capture remains one of the most-challenging issue to lower CO₂ emissions of existing power plants or heavy industry installations because of strong economy and energy efficiency aspects. The major issue comes from CO₂ dilution (4% for NGCC and 14% for PC) and the high flow rates to be treated. Furthermore, CO₂ purity has to be higher than 95% with recovery at 90%, to match the transportation/injection requirements.The MEA absorption process remains the reference today but its energy consumption (about 3 MJ/kg_CO2) and the amine consumption are still challenging drawbacks.The interest of CO₂ capture by indirect TSA (Temperature Swing Adsorption) was demonstrated experimentally in a previous work. The aim of this paper is to present the results of a numerical parametric study. Two main parameters are explored: the desorption temperature (100–200 °C) and the purge flow rate (0.1–0.5 Ndm³ min⁻¹). Four performance indicators are evaluated: CO₂ purity, recovery, productivity and specific energy consumption.Results show that purity above 95% can be achieved. Keeping the 95% target, it is possible to achieve recovery at 81% with productivity at 57.7 g_CO2/kg_ads h and a specific energy consumption of 3.23 MJ/kg_CO2, which is less than for the reference MEA process.Comparison with other adsorption processes exhibits that this process has good potential especially since some improvements are still expected from further research.     

Relationship between liquid depth and the acoustic generation of hydrogen: design aspect for large cavitational reactors with special focus on the role of the wave attenuation

Understanding the effect of the liquid depth (z) on the acoustic generation of hydrogen is highly required for designing large-scale sonoreactors for hydrogen production because acoustic cavitation is the central event that initiates sonochemical reactions. In this paper, we present a computational analysis of the liquid-depth effect on the generation of H₂ from a reactive acoustic bubble trapped in water irradiated with an attenuating sinusoidal ultrasound wave. The computations were made for different operating conditions of frequency (355–1000 kHz), acoustic intensity (1–5 W/cm²), and liquid temperature (10–30°C). The contribution of the acoustic wave attenuation on the overall effect of depth was appreciated for the different conditions. It was found that the acoustic generation of hydrogen diminished hardly with increasing depth up to z = 8 m, and the depth effect was strongly operating parameter-dependent. The sound wave attenuation played a crucial role in quenching H₂ yield, particularly at higher z. The reduction of the H₂ yield with depth was more pronounced at higher frequency (1000 kHz) and lower temperature (10°C) and acoustic intensity (1 W/cm²). The attenuation of the sound wave may contribute up to 100% in the overall reductive effect of depth toward H₂ production rate. This parameter could be imperatively included when studying all aspects of underwater acoustic cavitation.     

Thermal energy storage and thermodynamic properties of (E)-3-m-tolylbut-2-enoic acid as a medium temperature phase change material

Phase change materials (PCMs) that can store and release heat energy over the temperature range from 363 to 393 K are crucial for solar absorption cooling, and it is worthy to seek new solid-liquid PCMs candidates that melt and crystallize in this temperature range. In this paper, (E)-3-m-tolylbut-2-enoic acid (mTBEA) was applied as a PCM candidate. Its thermal energy storage properties and thermal stability were systematically investigated. The results showed that mTBEA melted at 382.9 ± 0.5 K and crystallized at about 364 K, with a melting enthalpy (Δ_fusH) of 138.4 ± 6.9 J g^?1 and showed good long-term cyclic stability and thermal stability. The supercooling of mTBEA was stabilized at about 20 K, indicating that the conservation condition of melted mTBEA could be simple. In addition, the melted mTBEA could release all the absorbed thermal energy upon crystallizing. Besides, mTBEA exhibited good thermal stability for it to be applied as PCM. Hence, mTBEA is a promising PCM candidate for solar absorption cooling. Furthermore, the heat capacity of mTBEA was measured by modulated temperature differential scanning calorimetry (MTDSC) over the temperature range from 198.15 to 431.15 K, and the molar thermodynamic functions, [H_T-H_298.15]_m and [S_T-S_298.15]_m, were calculated based on the fitted molar heat capacity data.     

Policy evaluation of vehicle exhaust standards in Japan from 1995 to 2005 based on two human health risk indices for air pollution and global warming

Measures for vehicle exhaust emissions aimed at reducing either air pollution or global warming could have counterproductive effects on one another. Increasing diesel passenger vehicles, which generally have lower CO₂ emissions than gasoline counterparts, leads to increasing particulate matter (PM) emissions, while gasoline has lower PM emissions than diesel. It is said that stringent limits on PM emission factors discourages improved CO₂ emission factors. Without including both effects in a risk evaluation, one cannot evaluate whether the total risk is reduced or not. Hence, we evaluated representative exhaust emission measures based on risk evaluation for both air pollution and global warming. Considering consumer choice between diesel and gasoline passenger vehicles and emissions standards adopted in Japan from 1995 to 2005, we built five cases for vehicle policy evaluation. For each case, we estimated disability-adjusted life years (DALY) as an index of human health risk caused by lung cancer linked to inhalation exposure of elemental carbon in PM as well as due to global warming linked to CO₂. The results of our risk evaluation reveal that the case adopting the 2005 new long-term Japanese emission standard reduces the human health risk caused by lung cancer due to air pollution by 0.6 × 10³ DALY, but would increase the risk due to global warming by 31.9 × 10³ DALY compared with the case of adopting EURO 4, for the same conditions of passenger vehicle choice from 1995. These results suggest that the characteristics of Japanese emissions standards are mainly designed to reduce air pollution.     

Phosphorus-doped graphene supported palladium (Pd/PG) electrocatalyst for the hydrogen evolution reaction in PEM water electrolysis

PEM water electrolysis is one of the most efficient methods for the production of hydrogen because of produced high purity of the gases and environmentally friendly. In the present study, Phosphorus-doped Graphene (PG) was synthesized by thermal annealing of triphenylphosphine (TPP) and graphene oxide (GO). The PG supported palladium (Pd/PG) electrocatalysts were synthesized by chemical reduction method and used as the cathode for hydrogen evolution reaction (HER) electrode. Structural properties and electrochemical performances of the synthesized Pd/PG electrocatalyst were studied by FE-SEM, EDS, ICP, FT-IR, XRD, and Cyclic voltammetry (CV) methods, respectively. The membrane electrode assemblies (MEA’s) were fabricated using Pd/PG as cathode for HER electrode and RuO₂ as anode for OER electrode. Also, their electrochemical performances along with the corresponding hydrogen yields were evaluated in single cell PEM water electrolyzer at various experimental conditions such as different current densities from 0.1 to 2.0 A cm^?2 and temperatures (28–80°C). The synthesized Pd/PG electrocatalyst was observed a current density of 1 A cm^?2 with 1.95 V at 80°C. Further, long-term stability studies were carried out continuously up to 2000 h which showed a reasonable stability. Hence, the synthesized Pd/PG can be used as an alternative to Pt-based electrocatalysts for the HER in PEM water electrolysis.