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RuO_(2) clusters derived from bulk SrRuO_(3):Robust catalyst for oxygen evolution reaction in acid

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Nano Research 2022年第3期15卷 1959-1965页

作者： Muwei Ji Xin Yang Shengding Chang Wenxing Chen Jin Wang Dongsheng He Yao Hu Qian Deng You Sun Bo Li Jingyu Xi Tomoaki Yamada Jiatao Zhang Hai Xiao Caizhen Zhu Jia Li Yadong Li College of Materials Science and Engineering Shenzhen UniversityShenzhen 518060China Institute of Low-Dimensional Materials Genome Initiative College of Chemistry and Environmental Engineering of Shenzhen UniversityShenzhen 518060China Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Materials Characterization and Preparation Center Southern University of Science and TechnologyShenzhen 518055China Department of Energy Engineering Nagoya UniversityFuro-choChikusa-kuNagoya 464-8603Japan Department of Chemistry Tsinghua UniversityBeijing 100084China

Developing highly efficient oxygen evolution reaction(OER)catalyst for the acidic corrosive operating conditions is a challenging task.Herein,we report the synthesis of uniform RuO_(2)clusters with~2 nm in size via electrochemical leaching of Sr from SrRuO_(3) ceramic in acid.The RuO_(2)clusters exhibit ultrahigh OER activity with overpotential of~160 mV at 10 mA·cm_(geo)^(−2) in 1.0 M HClO4 solution for 30-h testing.The extended X-ray absorption fine structure measurement reveals enlarged Jahn-Teller distortion of Ru-O octahedra in the RuO_(2)clusters compared to its bulk counterpart.Density function theory calculations show that the enhanced Jahn-Teller distortion can improve the intrinsic OER activity of RuO_(2).

关键词： oxygen evolution reaction RuO_(2)cluster electrochemical leaching acid solution

Effect of Morinda Tinctoria Leaves Extract on the Corrosion Inhibition of Mild Steel in acid Medium

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Acta Metallurgica Sinica(English Letters) 2013年第3期26卷 321-327页

作者： K.Krishnaveni J.Ravichandran A.Selvaraj PG and Research Department of Chemistry Sri Ramakrishna Mission Vidyalaya College of Arts and ScienceCoimbatore-641020 Tamilnadu India PG and Research Department of Chemistry CBM CollegeCoimbatore-641042 Tamilnadu India

The Morinda tinctoria (MT) plant leaves extract was prepared in aqueous and hydrochloric acid media and was used as corrosion inhibitor for mild steel in hydrochloric acid medium. MT is found to be an efficient inhibitor at room temperature and the efficiency decreases with increase in temperature. Results from colorimetric studies predict the amount of iron present in the test solution and the percentage inhibition efficiency values calculated from this data fit well with the weight loss experiments. The AC impedance studies reveal that the mild steel surface is positively charged and the process of inhibition is through charge transfer. Polarisation studies indicate the mixed nature of the inhibitor. Thermodynamic parameters obtained predict that the process of inhibition is a spontaneous one.

关键词： acid solution Mild steel Colorimetry Electrochemical technique Corrosion

Electrochemical Corrosion Behavior of Nd-Fe-B Sintered Magnets in Different acid solutions

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Journal of Rare Earths 2006年第2期24卷 218-222页

作者：郑精武姜力强陈巧玲 Department of Chemical and Materials Engineering Zhejiang University of Technology Hangzhou 310014 China Department

Electrochemical corrosion behavior of Nd-Fe-B sintered magnets in nitric acid, hydrochloric acid, sulfuric acid, phosphate acid and in oxalic acid was studied. Potentiodynamic polarization curves and immersion time dependence of corrosion rates of Nd-Fe-B sintered magnets in different acid solutions were tested. Microstructures of corroded Nd-Fe-B sintered magnets were investigated by means of SEM and AFM. The results indicate that in strong acid solutions of similar hydrogen ion concentration, the corrosion current increases in the order of HCl 〉 H3SO4 〉 HNO3 solution and Nd-Fe-B sintered magnets are passivated in phosphate acid and oxalic acid. Within 25 min, the corrosion rates of Nd-Fe-B sintered magnets in H2SO4 and H3PO4 solutions show a declining trend with immersion time, while in HNO3 and HCl solutions the corrosion rates are rising. And in H2C2O4 solution, weight of the magnets increases. The brim of Nd-Fe-B sintered magnets is corroded rather seriously and the size of the magnets changed greatly in nitric acid. The surfaces of the corroded magnets in the above mentioned acid solutions are all coarse.

关键词： Nd-Fe-B sintered magnets corrosion acid solution microstructure rare earths

Addition Mechanisms of Phenol toward Formaldehyde under acidic Condition: a Theoretical Investigation

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Chinese Journal of Structural Chemistry 2012年第6期31卷 821-828页

作者：徐文凤熊姗姗施豫庆李涛洪杜官本谢小光 Department of Chemistry Yunnan University Southwest Forestry University

The reaction mechanisms of phenol with formaldehyde in the first and second addition at the ortho- and para-position in acid solution were theoretically investigated at the PW91/DNP level with solvent effects included. The reaction of phenol with protonated methanediol firstly forms an adduct intermediate, via a SN2 mechanism with a water molecule as the leaving group. From the adduct intermediate, there are two reaction channels involving a proton transfer to form the addition products. One is that a proton directly transfers via a four-membered ring transition state with a notable energy barrier （Four-member mechanism）. Another mechanism involving a water molecule as catalyst to mediate the proton transfer （WCP mechanism）, is a barrierless process, indicating that the formation of the adduct intermediate, the first reaction step, is rate-limiting. The reaction products are free hydroxymethyl phenols and/or hydroxybenzy carbocation （HOC6H4CH2＋） which plays an important role in the following formation of methylene and methylene ether linkages. The second addition reactions between formaldehyde and hydroxymethyl phenol at all possible reaction sites of the phenol ring in acid solution were also investigated and discussed.

关键词： phenol formaldehyde reaction mechanism acid solution

Clinical Observation on Treatment of Acute Eczema by Wet Compress with Chinese Herbal Medicine

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Chinese Journal of Integrative Medicine 2002年第4期8卷 304-306页

作者： GAO Feng(高峰) Department of Dermatology The 7th People''s Hospital of ShenyangLiaoning(110003)

From April 1999 to Febuary 2001, a compara-tive observation on treatment of acute eczema bylocal wet compress with Chinese herbal medicineand local application of 3 % boric acid solution wascarried out in the author's... 详细信息

关键词： Chinese herbal acid solution

Electrochemical Corrosion Behavior of Zinc Alloys in Different acid solutions

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Electrochemical Corrosion Behavior of Zinc Alloys in Differe...