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排序方式: 共有189条查询结果,搜索用时 15 毫秒
1.
Zhengcheng Wang Shangyan Zhou Wei Liao Qian Zhou Meida Chen Jin Long Prof. Qingmei Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(66):e202201987
The designs of efficient and inexpensive Pt-based catalysts for methanol oxidation reaction (MOR) are essential to boost the commercialization of direct methanol fuel cells. Here, the highly catalytic performance PtFe alloys supported on multiwalled carbon nanotubes (MWCNTs) decorating nitrogen-doped carbon (NC) have been successfully prepared via co-engineering of the surface composition and electronic structure. The Pt1Fe3@NC/MWCNTs catalyst with moderate Fe3+ feeding content (0.86 mA/mgPt) exhibits 2.26-fold enhancement in MOR mass activity compared to pristine Pt/C catalyst (0.38 mA/mgPt). Furthermore, the CO oxidation initial potential of Pt1Fe3@NC/MWCNTs catalyst is lower relative to Pt/C catalyst (0.71 V and 0.80 V). Benefited from the optimal surface compositions, the anti-corrosion ability of MWCNT, strong electron interaction between PtFe alloys and MWCNTs and the N-doped carbon (NC) layer, the Pt1Fe3@NC/MWCNTs catalyst presents an improved MOR performance and anti-CO poisoning ability. This study would open up new perspective for designing efficient electrocatalysts for the DMFCs field. 相似文献
2.
Electrochemical oxidation of thio/carbohydrazide and their hydrazone derivatives Benzaldehyde thiocarbohydrazone [BTCH] diacetylene
thiocarbohydrazone [DATCH] have been studied in Brit-ton Robinson buffer in aqueous and nonaqueous media at a glassy carbon
electrode. The effects of pH, sweep rate, concentration, temperature and surfactants have been studied. The complex bis (carbo/thiocabohydrazide) Zn(II) chloride was also subjected to voltammetric analysis in order to understand the reactivity
both in free and metal bound states. The reaction conditions were optimized for the determination of above compounds in micrograms
quantities by differential pulse voltammetry, analytical utility of this investigation is also highlighted. 相似文献
3.
Electrooxidation of sulfide ion catalysed by microcrystals of cobalt phthalocyanine was investigated by cyclic voltammetry in 0.5M KNO3 at pH 9.22. Traces of catalyst were immobilized at the surface of a paraffin-impregnated graphite electrode by the mechanical transfer of its powder. The electro-oxidation of HS– proceeds in two irreversible steps, with the first peak between 0 V and –0.12 V and the second at 0.17 V. The first step is second order in HS– and its product is the adsorbed disulfide, which may further dissociate to give adsorbed sulfur atoms. The reduction of sulfur occurs at –0.1 V. 相似文献
4.
5.
V. V. Yanilkin V. I. Morozov F. F. Nigmadzyanov T. V. Gryaznova A. M. Kibardin 《Russian Chemical Bulletin》1998,47(8):1478-1480
Electrooxidation of 2-R-1,3-dibutyl-4,5-dimethyl-2,3-dihydro-1H-1,3,2-diazaphospholes with tri- and tetracoordinated phosphorus atoms were studied. Reversible one-electron oxidation gives
radical cations at potentials of −0.37 to +0.36 V. Magnetic parameters of the radical cations were measured.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1522–1524, August, 1998. 相似文献
6.
Electrochemical and electrocatalytic properties of thin films Au(111-25 nm), which are quasi-single-crystal electrodes 25
nm thick made of gold with the (111) preferential orientation, and same electrodes modified with a monolayer (ML) of palladium
are studied in 0.1 M solutions of HClO4 and H2SO4 employing voltammetric techniques and surface enhanced infrared reflection absorption spectroscopy (ATR-SEIRAS). Spectroscopic
experiments demonstrate strong adsorption of electrolyte species (H2O, OHads, anions) on the Pd surface. The weak and reversible adsorption of CO on Au(111-25 nm) does not change the interfacial-water
structure. Adsorption of CO on the Pd-modified film results in an irreversibly adsorbed CO adlayer stabilized by co-adsorbed
isolated water species. Various electrooxidation mechanisms are discussed. Electrochemical and spectroscopic investigations
on the adsorption and electrooxidation of HCOOH on bare and 1 ML Pd-Au(111-25 nm) electrodes reveal that electrooxidation
proceeds in both cases via a direct or dehydrogenation pathway. This mechanism involves the formation of formate as intermediate,
which is detected by in situ ATR-SEIRAS. The reactivity on Pd-modified surfaces is higher than on bare gold. The specifically
adsorbed anions (sulfate/bisulfate) and the oxide formation on the substrate surface lower the reactivity for CO and HCOOH
on both surfaces.
Published in Russian in Elektrokhimiya, 2006, Vol. 42, No. 11, pp. 1312–1329.
Based on the report delivered at the 8th International Frumkin Symposium “Kinetics of the Electrode Processes,” October 18–22,
2005, Moscow.
The text was submitted by the authors in English. 相似文献
7.
Santiago MB Vélez MM Borrero S Díaz A Casillas CA Hofmann C Guadalupe AR Colón JL 《Electroanalysis》2006,18(6):559-572
We present a carbon paste electrode (CPE) modified using the electron mediator bis(1,10‐phenanthroline‐5,6‐dione)(2,2′‐bipyridine)ruthenium(II) ([Ru(phend)2bpy]2+) exchanged into the inorganic layered material zirconium phosphate (ZrP). X‐Ray powder diffraction showed that the interlayer distance of ZrP increases upon [Ru(phend)2bpy]2+ intercalation from 10.3 Å to 14.2 Å. The UV‐vis and IR spectroscopies results showed the characteristic peaks expected for [Ru(phend)2bpy]2+. The UV‐vis spectrophotometric results indicate that the [Ru(phend)2bpy]2+ concentration inside the ZrP layers increased as a function of the loading level. The exchanged [Ru(phend)2bpy]2+ exhibited luminescence even at low concentration. Modified CPEs were constructed and analyzed using cyclic voltammetry. The intercalated mediator remained electroactive within the layers (E°′=–38.5 mV vs. Ag/AgCl, 3.5 M NaCl) and electrocatalysis of NADH oxidation was observed. The kinetics of the modified CPE shows a Michaelis–Menten behavior. This CPE was used for the oxidation of NADH in the presence of Bakers' yeast alcohol dehydrogenase. A calibration plot for ethanol is presented. 相似文献
8.
L. A. Shundrin I. G. Irtegova A. D. Rogachev V. A. Reznikov 《Russian Chemical Bulletin》2005,54(5):1178-1184
The electrochemical reduction of 3,3′-bi(2-R-5,5-dimethyl-4-oxopyrrolinylidene) 1,1′-dioxides (R = CF3, Me, Ph, But), which are cyclic dinitrons with conjugated C=C bond, in acetonitrile is an EE process producing stable radical anions and
dianions, whereas the electrochemical oxidation is an EEC (R = Me, Ph) or EE process (R = But) with formation of radical cations (except for the case of R = CF3) and dications (R = But) stable under standard conditions. Radical cations of the dioxides with R = Me, Ph, and But and radical anions of the whole series of the compounds studied, including R = CF3, were characterized by ESR spectroscopy combined with electrochemical measurements and quantum-chemical calculations. The
electrochemical behavior of the But-substituted dinitron is unique: the EE processes in the region of negative and positive potentials with formation of the
dianion, radical anion, radical cation, and dication stable at T = 298 K were observed for the first time within one cycle of potential sweep in the CV curve measured in MeCN.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1148–1154, May, 2005. 相似文献
9.
10.
采用欠电位沉积(upd)方法在Pt 表面沉积亚单层的Ru制备出upd-Ru/Pt 电极. 通过欠电位沉积前后电极在0.5 mol·L-1 H2SO4溶液中循环伏安图-152 - 128 mV(vs Ag/AgCl)电位范围内对氢区的数值积分确定Pt表面Ru 的覆盖度. 用电化学方法测试了甲醇在upd-Ru/Pt电极上的催化氧化, 并讨论分析了欠电位沉积电位和Ru的表面覆盖度对甲醇氧化的影响. 结果表明, Ru能够欠电位沉积到Pt表面. Pt表面欠电位沉积少量的Ru 即能大大促进甲醇的氧化.只要控制upd-Ru的沉积量, upd-Ru原子就能大大促进甲醇氧化而与沉积电位无关. Ru原子对甲醇氧化的促进作用与Ru和Pt是否形成合金无关, 而取决于Ru 在Pt表面的百分含量. 相似文献