RuO_(2)/CoMO_(2)O_(x) Catalyst with Low Ruthenium Loading for Long-Term Acidic Oxygen Evolution

We must urgently synthesize highly efficient and stable oxygen-evolution reaction(OER) catalysts for acidic media. Herein, we constructed a series of Ti mesh(TM)-supported RuO_(2)/CoMo_(y)O_(x) catalysts(RuO_(2)/CoMo_(y)O_(x)/TM) with heterogeneous structures. By optimizing the ratio of Co to Mo, RuO_(2)/CoMO_(2)O_(x)/TM with low Ru loading(0.079 mg/cm^(2)) achieves remarkable OER performance(η = 243 mV at 10 mA/cm^(2)) and high stability(300 h @ 10 mA/cm^(2)) in 0.5 mol/L H_(2)SO_(4) electrolyte. The activity of RuO_(2)/CoMo_yO_x/TM can be maintained for 50 h at 100 mA/cm^(2), and a water electrolyzer with RuO_(2)/CoMO_(2)O_(x)/TM as anode can operate for 40 h at 100 mA/cm~2, suggesting the remarkable OER durability of RuO_(2)/CoMo__(y)O__(x)/TM in acidic electrolyte. Owing to the heterogeneous interface between CoMO_(2)O_(x) and RuO_(2), the electronic structure of Ru atoms was optimized and electron-rich Ru was formed. With modulated electronic properties, the dissociation energy of H_(2)O is weakened, and the OER barrier is lowered. This study provides the design of low-cost noble metal catalysts with long-term stability in an acidic environment.

Baeyer-Villiger oxidation of cyclic ketones utilizing potassium peroxydisulfate(K_2S_2O_8) or sodium perborate(NaBO_3) in acidic media

The efficient, green, facile, mild and straightforward conversion procedure for the oxidation of cyclic ketones to lactones at room temperature utilizing potassium peroxydisulfate （K2S2O8） in acidic media is satisfactory to high yields without using traditional chlorinated solvents is reported. This oxidative reagent is cheap and friendly environmental procedure for industrial purposes than use of organic peracids.

Recent progress of precious-metal-free electrocatalysts for efficient water oxidation in acidic media

The realization of efficient oxygen evolution reaction(OER) is critical to the development of multiple sustainable energy conversion and storage technologies, especially hydrogen production via water electrolysis. To achieve the massive application of hydrogen energy and mass-scale hydrogen production from water splitting drives the pursuit of competent precious-metal-free electrocatalysts in acidic media, where the hydrogen evolution reaction(HER) is more facilitated. However, the development of high-efficient and acid-stable OER electrocatalysts, which are robust to function stably at high oxidation potentials in the acidic electrolyte, remains a great challenge. This article contributes a focused, perceptive review of the up-to-date approaches toward this emerging research field. The OER reaction mechanism and fundamental requirements for oxygen evolution electrocatalysts in acid are introduced. Then the progress and new discoveries of precious-metal-free active materials and design concepts with regard to the improvement of the intrinsic OER activity are discussed. Finally, the existing scientific challenges and the outlooks for future research directions to the fabrication of emerging, earth-abundant OER electrocatalysts in acid are pointed out.

Engineering Ru(IV)charge density in Ru@RuO2 core-shell electrocatalyst via tensile strain for efficient oxygen evolution in acidic media

The design of efficient Ru-based electrocatalysts with high intrinsic activities for acidic water oxidation is highly desirable and challenging for water splitting in proton exchange membrane electrolyzers.Here,for the first time,we engineer the charge density of Ru(IV)by creating tensile strains in the RuO2 shell of Ru@RuO2 core-shell nanoparticles,viz.Ru@RuO2-L.High-resolution spectroscopic characterizations confirm the presence of av.6%tensile strain in Ru-O bonds,which results in an effective reduction of the Ru(IV)charge density.The resultant Ru^X+(4<X<5)active sites greatly accelerate the oxygen evolution reaction(OER)in an acidic electrolyte,leading to a remarkably low overpotential of 191 mV at 10 mA cm^-2.These values are lower than those for the benchmark RuO2 catalyst and are also among the lowest for efficient Ru-based electrocatalysts reported thus far.The specific activity and mass activity are also greatly enhanced 4.2-fold and 17.7-fold compared to those of RuO2,respectively.The acidic OER activity improvement is ascribed to the lowered adsorption energy of*OOH,owing to the reduced charge density of Ru(IV),and the rapid charge transport owing to the Ru core.Ru@RuO2-L also demonstrates high feasibility as the anode catalyst for the overall water splitting in acidic media.

Recent advances in electrocatalytic oxygen reduction for on-site hydrogen peroxide synthesis in acidic media

Electrocatalytic oxygen reduction reaction (ORR) via two-electron pathway is a promising approach to decentralized and on-site hydrogen peroxide (H_(2)O_(2)) production beyond the traditional anthraquinone process.In recent years,electrochemical H_(2)O_(2) production in acidic media has attracted increasing attention owing to its stronger oxidizing capacity,superior stability,and higher compatibility with various applications.Here,recent advances of H_(2)O_(2) electrosynthesis in acidic media are summarized.Specifically,fundamental aspects of two-electron ORR mechanism are firstly presented with an emphasis on the pH effect on catalytic performance.Major categories of promising electrocatalysts are then reviewed,including noble-metal-based materials,non-noble-metal single-atom catalysts,non-noblemetal compounds,and metal-free carbon-based materials.The innovative development of electrochemical devices and in situ/on-site application of electrogenerated H_(2)O_(2) are also highlighted to bridge the gap between laboratory-scale fundamental research and practically relevant H_(2)O_(2) electrosynthesis.Finally,critical perspectives on present challenges and promising opportunities for future research are provided.

Corrosion inhibition effect of N, N′-bis(2-pyridylmethylidene)-1,2-diiminoethane on AZ91D magnesium alloy in acidic media

The inhibition effect of electrochemical noise, EIS and surface analysis to evaluate N'-bis (2-pyridylmethylidene)- 1,2-diiminoethane (BPIE) Schiff base against AZ91D alloy corrosion in 0.01 mol/L HCl was investigated by different electrochemical methods. Potentiodynamic polarization curves revealed that the BPIE acts as a mixed-type corrosion inhibitor. Electrochemical impedance spectroscopy (EIS) measurements confirmed the corrosion inhibition effect of the BPIE. As the inhibitor concentration increased, the charge transfer resistance increased and the double layer capacitance decreased due to more inhibitor adsorption on the surface. The results obtained by analysis of electrochemical noise (EN) data in time and frequency domains are in good agreement with EIS and polarization results. Moreover, scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) were used to investigate the corrosion inhibition of the BPIE. SEM images showed that the corrosion damage of the alloy surface reduced in the presence of BPIE. The intensity of the XRD peaks corresponding to magnesium-rich α phase increased in the presence of BPIE, indicating lower corrosion of alloy sample. Also, EDX analysis approved the corrosion inhibition performance of the BPIE. The studied Schiff base compound acts by physical adsorption on the alloy surface and its adsorption obeys the Langmuir isotherm.

Ultrasmall Pt_(2)Sr alloy nanoparticles as efficient bifunctional electrocatalysts for oxygen reduction and hydrogen evolution in acidic media

Electrocatalytic oxygen reduction reaction(ORR)and hydrogen evolution reaction(HER)in acidic media are vital for the applications of renewable energy electrolyzers.However,the low mass activity of noble Pt urgently needs to be improved due to the strong binding energetics of oxygen species(*O)with Pt sites.Here we report fine PtxSr alloy(-2 nm)supported on N-doped carb on(NC)pyrolyzing from ZIF-8 as bifunctional electrocatalysts toward ORR and HER in acidic media.The representative Pt_(2)Sr/NC exhibits an onset potential of 0.94 V vs.RHE and half-wave potential of 0.84 V toward ORR,and a low over-potential of 27 mV(10 mA cm^(-2))toward HER,respectively.Significantly,the mass activities of Pt_(2)Sr/NC are 6.2 and 2.6 times higher than that of Pt/C toward ORR(at 0.9 V)and HER(at-30 mV),respectively.Simultaneously,Pt_(2)Sr/NC possesses a retention rate of 90.97%toward acidic ORR after 35000 s of continuous operation.Through density functional theory(DFT)calculations and X-ray photoelectron spectroscopy analysis,the incorporation of Sr into Pt forming Pt_(2)Sr alloy redistributes the electronic structures of Pt-Pt bonds,changing the rate-determining step for the ORR on Pt sites from the formation of*OH from*O to the generation of*OOH along with decreasing the energy barrier,which is also confirmed by the downshift of d band center.Meanwhile,the downshift of d band center also leads to the optimization of the adsorption energy(H*)with Pt,significantly improving Pt_(2)Sr/NC toward HER.

An Fe-N/S-C hybrid electrocatalyst derived from bimetal-organic framework for efficiently electrocatalyzing oxygen reduction reaction in acidic media

Heteroatoms doped Fe-N-C electrocatalysts have been widely acknowledged as one of the most promising candidates to replace Pt-based materials for electrocatalyzing oxygen reduction reaction(ORR).However,the complicated synthesis method and controversial catalytic mechanism represent a substantial impediment as of today.Herein,a very facile strategy to prepare Fe-N/S-C hybrid through pyrolyzing Zn and Fe bimetallic MOFs is rationally designed.The electrocatalytic ORR performance shows a volcanotype curve with the increment of added Fe content.The half-wave potential(E1/2) for ORR at optimized Fe-N/S-C-10%(10%=n(Fe)/(n(Fe)+n(Zn)),n(Fe) and n(Zn) represent the moles of Fe2+ and Zn2+ in the precursors,respectively) shifts significantly to the positive direction of 19.6 mV with respect to that of Pt/C in acidic media,as well as a high 4 e selectivity and methanol tolerance.After 10,000 potential cycles,E1/2 exhibits a small negative shift of-27.5 mV at Fe-N/S-C-10% compared favorably with Pt/C(~141.0 mV).This can be attributed to:(ⅰ) large specific surface area(849 m^(2)/g) and hierarchically porous structure are favorable for the rapid mass transfer and active sites exposure;(ⅱ) the embedded Fecontaining nanoparticles in porous carbon are difficult to be moved and further agglomerated during the electrochemical accelerated aging test,further improving its stability;(ⅲ) there exist small Fecontaining nanoparticles,uniformly doped N and S,abundant Fe-N as efficiently active sites.This work represents a breakthrough in the development of high-efficient non-precious-metal catalysts(NPMCs)to address the current Pt-based electrocatalysts challenges.

Glyoxylic acid as catalyst:A simple selective synthesis of 1,2-disubstituted benzimidazoles in aqueous media

Glyoxylic acid （5 mol%） performs as a novel highly water-soluble catalyst for the synthesis of 2-aryl-l-arylmethyl-lH- benzimidazoles from a wide range of substituted o-phenylenediamines and various substituted aldehydes in good to excellent isolated yields （85-95%） using water as solvent at ambient temperature. The remarkable advantages offered by this method are easily and inexpensive available catalyst, simple procedure, mild conditions, much faster （20--40 rain） reactions and excellent yields of products.

Beneficial effects of vincamine with thioctic acid and lutein on retinal and optic nerve functions in an opaque media

AIM: To detect whether the combination of vincamine, thioctic acid and lutein will improve the retina and optic nerve functions in cases of an opaque media with an optic nerve and/or a retinal defect or not.METHODS: Totally 2000 patients(2000 eyes) of corneal opacities with defects in the optic nerve or/and the retinal functions were studied. Every patient received three types of drugs: thioctic acid with cyanocobalamine, vincamine, and lutein. The drugs were given daily for 3-12 mo according to patient’s responses. Full field flash electroretinogram(ERG) and flash visual evoked potential(VEP) were done before treatment and at 1, 3, 6, and 12 mo sequentially. Patients were followed up for 12 mo.RESULTS: In the 2000 eyes, 1000 eyes had both moderate optic nerve and retinal function defects;and 840 eyes out of the 1000 improved with the medical treatment. Another 500 eyes out of the 2000 eyes had extinguished retinal function with normal optic nerve function and only 125 eyes of them improved. The 290 out of the 2000 eyes had severe defects in optic nerve with normal retinal function and 130 of them improved. Another 210 eyes have mild optic nerve and retinal function defects and 194 improved.CONCLUSION: The combination of vincamine, thioctic acid with cyanocobalamine, and lutein improved both retina and optic nerve functions mainly in mild and moderate defect than in severe cases.

Fixed-Bed Column Adsorption Modeling of MnO4- Ions from Acidic Aqueous Solutions on Activated Carbons Prepared with the Biomass

Activated carbons calcined at 400˚C and 600˚C (AC-400 and AC-600), prepared using palm nuts, collected in the town of Franceville in Gabon, were used to study the dynamic adsorption of MnO4- ions in acidic media on fixed bed column and on the kinetic modeling of experimental data of breakthrough curves of MnO4- ions obtained. Results on the adsorption of MnO4- ions in fixed-bed dynamics obtained on AC-400 and AC-600 adsorbents beds indicated that the AC-400 bed appears to be the most efficient in removing MnO4- ions in acidic media. Indeed, the adsorbed amounts, the adsorbed capacities at saturation and the elimination percentage of MnO4- ions obtained with AC-400 (31.24 mg;52.06 mg·g-1 and 41.65% respectively) were higher compared to those obtained with AC-600 (9.87 mg;16.45 mg·g-1 and 17.79% respectively). The breakthrough curves kinetic modeling revealed that the Thomas model and the pseudo-first-order kinetic model were the most suitable models to describe the adsorption of MnO4- ions on adsorbents studied in our experimental conditions. The results of the intraparticle diffusion model showed that intraparticle diffusion was involved in the adsorption mechanism of MnO4- ions on investigated adsorbents and was not the limiting step and the only process controlling MnO4- ions adsorption. In contrast to AC-400, the intraparticle diffusion on AC-600 bed plays an important role in the adsorption mechanism of MnO4- ions.

Organic Media Enhanced Spectrofluorimetric Determination of L-Ascorbic Acid

A novel spectrofluorimetric method for the determination of L ascorbic acid is proposed. It is based on the inhibition of L ascorbic acid on the formation of 2,3 diaminophenazine, which is an oxidation product of o phenylenediamine catalyzed by laccase .The fluorescence (at λ ex /λ em =464 nm /530 nnm) was enhanced strongly in the presence of organic media . The mechanism of o phenylenediamine oxidation reaction catalyzed by laccase in the presence of L ascorbic acid is discussed .L ascorbic acid is determined in the ethanol, 1,4 dioxane and acetone over the linear range of 4.0×10 -7 ～1.2×10 -4 mol/L, 4.0×10 -7 ～ 8.0×10 -5 mol/L and 4.0×10 -7 ～1.0×10 -4 mol/L with a detection limit of 1.20×10 -8 mol/L,1.19×10 -8 mol/L and 1.24×10 -8 mol/L, respectively. The method has been successfully applied to the simple and rapid determination of L ascorbic acid in pharmaceuticals and milk powder.

Pause electrolysis for acidic CO_(2) reduction on 3-dimensional Cu

Electrochemical CO_(2) reduction reaction(CO_(2) RR)exhibits remarkable potential in producing valuable chemicals with renewable energy.Operating CO_(2) RR in acidic media is beneficial to solve the issue of low carbon utilization brought by(bi)carbonate formation at the cathode.Suppressing the competing hydrogen evolution reaction and achieving stable CO_(2) RR performance remains challenging.Herein,we constructed a 3-dimensional Cu(3D-Cu)gas diffusion electrode(GDE)to achieve efficient C_(2)H_(4) production with a partial current density(j C_(2)H_(4))of over 470 mA cm^(2) and a Faradaic efficiency(FE C_(2)H_(4)) of 40%.With pause electrolysis,the decay rate of the j C_(2)H_(4) is only half that of the traditional constant electrolysis.The GDE after constant electrolysis was found to suffer from severe salt formation,leading to the decreased activity and poor stability.

Synthesis of bis(indolyl) methanes using aluminiumoxide(acidic) in dry media

Heterogeneous catalyst aluminium oxide(acidic) is found to be an effective catalyst for the solvent-free condensation reaction of indole with aldehydes in microwave irradiation with shorter reaction time and higher yields.

Synthesis of 3,3-Arylidene Bis(4-Hydroxycoumarin) Catalyzed by <i>p</i>-Dodecylbenzenesulfonic Acid (DBSA) in Aqueous Media and Microwave Irradiation

A series of 3,3-arylidene bis(4-hydroxycoumarins) were synthesized by the reaction of aromatic aldehydes with 4-hydroxycoumarin using dodecylbenzenesulfonic acid as Br?nsted acid-surfactant catalyst in aqueous media and under microwave irradiation. The present method is operationally simple and the use of water as the reaction medium makes the process environmentally benign.

Phosphorous and selenium tuning Co-based non-precious catalysts for electrosynthesis of H_(2)O_(2)in acidic media

Electrosynthesis of hydrogen peroxide(H2O2)is an on-site method that enables independent distribution applications in many fields due to its small-scale and sustainable features.The crucial point remains developing highly active,selective and cost-effective electrocatalysts.The electrosynthesis of H2O2 in acidic media is more practical owing to its stability and no need for further purification.We herein report a phosphorus and selenium tuning Co-based non-precious catalyst(CoPSe)toward two-electron oxygen reduction reaction(2e–ORR)to produce H2O2 in acidic media.The starting point of using both P and Se is finding a balance between strong ORR activity of CoSe and weak activity of CoP.The results demonstrated that the CoPSe catalyst exhibited the optimized 2e–ORR activity compared with CoP and CoSe.It disclosed an onset potential of 0.68 V and the H2O2 selectivity 76%-85%in a wide potential range(0–0.5 V).Notably,the CoPSe catalyst overcomes a significant challenge of a narrow-range selectivity for transitionmetal based 2e–ORR catalysts.Finally,combining with electro-Fenton reaction,an on-site system was constructed for efficient degradation of organic pollutants.This work provides a promising non-precious Co-based electrocatalyst for the electrosynthesis of H2O2 in acidic media.

制油技术和储藏条件对高油酸花生油品质的影响

为更好地把控花生油的品质和安全,研究了不同炒制温度(132、137、142℃)、过滤介质(厚布/薄布/滤纸板、花生饼层/厚布/薄布、助滤剂/厚布/薄布、厚布/薄布)、储藏条件(室内储藏、室外储藏)对高油酸花生油品质的影响。结果表明:选择炒制温度为137℃,采用花生饼层/厚布/薄布作为过滤介质,能够获得风味与品质俱佳的高油酸花生油,且这种优化能够降低生产成本,为企业节约资源;随着储藏时间的延长和温度的升高,普通花生油和高油酸花生油的酸值和过氧化值均逐渐升高,且酸值变化较小,过氧化值变化显著,在25℃室内储藏182 d时,普通花生油和高油酸花生油的过氧化值涨幅分别为398%和77%,而在45℃室内储藏182 d时,2种花生油过氧化值的涨幅分别为927%、271%;在室外储藏45 d,未包裹瓦楞纸的普通花生油与高油酸花生油的过氧化值涨幅分别为582%和87%,经过瓦楞纸包裹处理后,2种花生油的过氧化值涨幅分别为116%、19%。综上,在不同储藏条件下,高油酸花生油均展现出较好的储藏稳定性,且低温、使用瓦楞纸进行包裹更有利于其储藏。

Cr30钢表面镍包WC增强铁基合金涂层的微观组织和耐磨耐蚀性能研究

为改善Cr30钢表面的耐冲蚀磨损性能以及耐硫酸、盐酸腐蚀性能,以铁合金粉和镍包WC颗粒的混合物为原料,采用激光熔覆技术在Cr30钢表面制备含镍包WC铁基合金涂层,研究了原料中镍包WC质量分数(10%~30%)对铁基合金涂层的显微组织、物相组成、显微硬度、耐冲蚀磨损性能、耐硫酸和盐酸腐蚀性能的影响。结果表明:不含镍包WC的铁基合金涂层物相为FeCr固溶体和Cr_(23)C_(6);含10%和20%镍包WC的铁基合金涂层物相为FeCr固溶体、Cr_(23)C_(6)和Fe3W3C;随着镍包WC含量增至30%,铁基合金涂层中析出了新的碳化物Fe_(6)W_(6)C,含30%镍包WC的铁基合金涂层物相为FeCr固溶体、Cr_(23)C_(6)、F_(e)3W_(3)C和Fe_(6)W_(6)C。随着镍包WC含量的增加,铁基合金涂层的显微硬度、耐冲蚀磨损和耐硫酸、盐酸腐蚀性能提高,当镍包WC质量分数为30%时,铁基合金涂层的组织致密、细化效果最明显,涂层的硬度最高,达到786 HV_(0.5);30%镍包WC的铁基合金涂层的耐冲蚀磨损、耐硫酸和盐酸腐蚀性能最佳。

血尿酸水平与高血压患者颈动脉内-中膜厚度的相关性分析

目的探讨高血压患者血尿酸(SUA)水平与颈动脉内-中膜厚度(CIMT)的相关性。方法采用回顾性研究,选取西安市中医医院2020年3月至10月被诊断为高血压的患者110例。其中,单纯高血压患者60例[HT组,男31例,女29例,年龄(51.59±10.84)岁],高血压合并高尿酸血症者50例[HT+HU组,男23例,女27例,年龄(52.27±10.12)岁]。另外,选取健康体检者40名[健康对照组,男20例,女20例,年龄(51.23±9.43)岁]。比较各组之间的血压、体重指数(BMI)、甘油三酯、总胆固醇、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、SUA、CIMT的差异,分析SUA水平与CIMT的相关性。统计学方法采用单因素方差分析、χ^(2)检验、偏相关分析、多元线性回归分析。结果3组之间性别、年龄、心率、吸烟、总胆固醇、甘油三酯、HDL-C、LDL-C比较,差异均无统计学意义(均P>0.05);HU+HT组SUA水平高于对照组与HT组[(496.52±74.82)µmol/L比(253.42±80.46)µmol/L比(267.78±75.72)µmol/L],差异有统计学意义(F=156.14,P<0.05);HT组与HU+HT组的收缩压、舒张压均高于对照组[(164.72±12.86)mmHg(1mmHg=0.133kPa)比(165.87±12.96)mmHg比(106.75±7.46)mmHg、(98.82±6.56)mmHg比(98.78±6.85)mmHg比(73.68±4.66)mmHg],差异均有统计学意义(F=366.07、239.34,均P<0.05);HU+HT组与HT组的CIMT均高于对照组,HU+HT组高于HT组与对照组[(1.02±0.18)mm比(0.85±0.19)mm比(0.60±0.11)mm],差异有统计学意义(F=68.95,P<0.05)。偏相关分析显示,HU+HT组患者的SUA水平与CIMT水平正相关(r=0.42,P<0.05)。多因素线性回归分析显示,SUA水平是高血压患者CIMT的独立影响因素(P<0.05)。结论高血压合并高尿酸血症患者的CIMT增厚显著,高血压患者SUA水平与CIMT密切相关,当高血压患者合并高尿酸血症时,进一步加重了动脉粥样硬化等心血管疾病的进程。

烹饪方法对食材营养成分的影响研究

本文分析了煮、蒸和炒3种常见烹饪方式对食材营养成分的影响,发现煮易导致蛋白质变性、脂肪氧化和维生素流失,蒸虽能保留部分矿物质,但维生素C损失严重,而炒可能导致蛋白质和脂肪的过度破坏。为保护食材营养,提出了低温烹调、合理搭配酸碱介质、优化烹饪时间与火候的策略。这些措施旨在减少烹饪过程中营养成分的损失,提高食物的营养价值,为人们提供科学的烹饪建议。