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381.
本文构建了一种以还原氧化石墨烯( RGO) 为电子中继体的复合光催化体系 Pt-RGO / ZnIn2S4 - CoPi / BiVO4 ,并分别利用若丹明 B(RhB)的脱色和光催化分解水测试其催化性能。 在 RhB 的光催化脱色实验 中,反应 3h 后,溶液中 RhB 的脱色率高达 99. 89%。 在光催化分解水的过程中,反应 5h 之后,复合催化剂体 系产 H2 量达到 359. 6μmol,产氧量达到 196. 3μmol。 探讨了复合光催化剂体系的工作机理,发现其卓越的光 催化水处理效能主要缘于 RGO 作为电子中继体促进了光生电子在两个复合单体之间的传导,从而提高了系 统的光催化性能。 相似文献
382.
Elnaz Ranjbakhsh Mohammad Izadyar Ali Nakhaeipour Aziz Habibi-Yangjeh 《International journal of quantum chemistry》2020,120(23):e26388
The photocatalytic yield of g-C3N4 for CO2 reduction was modified by phosphorus doping. Possible reaction pathways for CO2 reduction on the P-doped g-C3N4 (PCN) surface were investigated by density function theory calculations for the first time. The experimental results showed that P doping increases the carriers' lifetime, which improves the production of CH4 through the increase in the driving force of the electrons. The partial density of states of the PCN showed that the valence band maximum and conduction band minimum are composed of px, py, and, s orbitals of the N atoms and pz states of carbon, nitrogen, and phosphorus, respectively. Mechanism studies confirm that formic acid, formaldehyde, methanol, and methane are the most probable products. Methane, having positive adsorption energy, can be easily desorbed from the PCN surface, and the Gibbs activation energy of the final step is 1.98 eV. The formation of H2COOH is the rate-determining step. 相似文献
383.
溶胶-凝胶法制备薄膜型TiO2光催化剂 总被引:26,自引:0,他引:26
用TiCl4作原料,通过溶胶-凝胶法在单晶硅基片上制备了TiO2纳米薄膜,并用XRD,AES,XPS以及紫外反射光谱等手段,对TiO2薄膜的结构进行了研究.结果发现,TiO2薄膜以锐钛矿型晶相存在.TiO2薄膜层与硅衬底间无明显的界面扩散反应.掺杂的Pd在还原前的薄膜中以氧化态存在,还原后则以高分散的金属态存在.掺杂的Pt在还原前后均以金属态存在,但还原后产生颗粒聚集.掺杂Pd的TiO2薄膜经还原后,其紫外吸收强度明显提高,主吸收峰发生红移. 相似文献
384.
高度分散的Pt/TiO2的制备及光催化活性 总被引:1,自引:0,他引:1
用柠檬酸作为空穴捕获剂和分散剂, 在温和条件下用光催化还原法将3 nm金属铂沉积在7 nm的锐钛矿相及介孔二氧化钛纳米晶表面. TEM观察显示铂的负载量为w=1.0%时, 多数二氧化钛纳米晶表面沉积了岛状的铂团簇, XPS和电子衍射结果表明铂以游离态存在. 负载w=1.0%~2.0%铂的TiO2在苯酚光氧化反应中活性显著提高. Pt/TiO2在氨气中经550 ℃氮化, 可制得氮掺杂的Pt/TiO2可见光光催化剂, 氮化过程中铂团簇没有烧结和显著长大. 相似文献
385.
Nicholas A.D. Burke Markus Templin James E. Guillet 《Journal of photochemistry and photobiology. A, Chemistry》1996,100(1-3):93-100
The photo-oxidation of perylene in aqueous solutions of a polymeric photocatalyst was investigated to probe the mechanism of polycyclic aromatic hydrocarbon degradation. Perylene and other hydrophobic molecules are efficiently solubilized in aqueous polymer solutions with distribution coefficients as high as 4 x 106. The rate of perylene photo-oxidation was much more rapid in aqueous polymer solutions than in organic solvents. In organic solvents, 102 sensitizers (rose bengal) had little effect on the reaction, but electron acceptors, such as dicyanobenzene, caused an acceleration in rate. Naphthoquinone was suggested as a potential electron acceptor in the naphthalene-containing polymer, and it was shown to be formed in small concentrations by polymer oxidation. It was concluded that the polymer plays several key functions in perylene photo-oxidation: (1) solubilization of the hydrophobic molecule; (2) energy migration through the polymer coil and energy transfer, providing additional photochemical energy to the reactants; (3) the enhancement of oxidation by photoinduced electron transfer via provision of an electron acceptor and facilitation of charge separation. 相似文献
386.
387.
Visible‐light‐driven plasmonic photocatalyst Ag‐TiO2 nanocomposite hollow spheres are prepared by a template‐free chemically‐induced self‐transformation strategy under microwave‐hydrothermal conditions, followed by a photochemical reduction process under xenon lamp irradiation. The prepared samples are characterized by using scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, N2 adsorption‐desorption isotherms, X‐ray photoelectron spectroscopy, UV/Vis and Raman spectroscopy. Production of ?OH radicals on the surface of visible‐light illuminated TiO2 was detected by using a photoluminescence method with terephthalic acid as the probe molecule. The photocatalytic activity of as‐prepared samples was evaluated by photocatalytic decolorization of Rhodamine B (RhB) aqueous solution at ambient temperature under visible‐light irradiation. The results show that the surface plasmon absorption band of the silver nanoparticles supported on the TiO2 hollow spheres was red shifted, and a strong surface enhanced Raman scattering effect for the Ag‐TiO2 nanocomposite sample was observed. The prepared nanocomposite hollow spheres exhibits a highly visible‐light photocatalytic activity for photocatalytic degradation of RhB in water, and their photocatalytic activity is higher than that of pure TiO2 and commercial Degussa P25 (P25) powders. Especially, the as‐prepared Ag‐TiO2 nanocomposite hollow spheres at the nominal atomic ratio of silver to titanium ( R ) of 2 showed the highest photocatalytic activity, which exceeds that of P25 by a factor of more than 2. 相似文献
388.
Takahiro Takei Rie Haramoto Nobuhiro Kumada Nobukazu Kinomura Shunsuke Nishimoto Michihiro Miyake 《Journal of solid state chemistry》2011,184(8):2017-2022
LiBiO3, NaBiO3, MgBi2O6, KBiO3, ZnBi2O6, SrBi2O6, AgBiO3, BaBi2O6 and PbBi2O6 were synthesized by various processes such as hydrothermal treatment, heating and so on. These materials were examined for their photocatalytic activities in the decolorization of methylene blue and decomposition of phenol under visible light irradiation. For methylene blue decolorization, the presence of KBiO3 resulted in complete decoloration within 5 min. For phenol decomposition, NaBiO3 showed the highest activity, while LiBiO3, SrBi2O6 and BaBi2O6 possessed almost comparable decomposition rates. Their decomposition rates were apparently higher than that by anatase (P25) under UV irradiation. 相似文献
389.
TiO2膜光催化剂的改进及表征 总被引:4,自引:0,他引:4
提出用粉末-溶胶法制备TiO2薄膜型光催化剂,介绍了粉溶法的制备工艺及改变pH值对催化活性的影响.研究结果表明, 利用粉溶法或添加浓HNO3后制备的TiO2薄膜光催化剂表现出了较高的光催化活性.结合结构表征详细分析了其中的原因.认为粉溶法制备的催化剂表面更粗糙,比表面积增大,膜厚度减小,这些都可能是其催化活性提高的原因.而加酸后膜催化活性提高主要是因为酸性条件下表面几乎没有Ti3+表面态,利于光生电子与光生空穴的分离. 相似文献
390.
ZnO和TiO2粒子的光催化活性及其失活与再生 总被引:35,自引:0,他引:35
利用XRD,TEM,BET和UV-Vis等测试技术对商品的ZnO及TiO2和纳米ZnO及TiO2粒子进行了表征.无论是商品的还是纳米的,在光催化氧化降解气相n-C7H16和SO2及液相苯酚的反应中,TiO2均表现出比ZnO高的光催化活性,并从光腐蚀性和表面电荷两方面分析了其原因.在光催化氧化降解n-C7H16的反应中,ZnO粒子易失活,而TiO2粒子不易失活.但是,在光催化氧化降解SO2的反应中,ZnO和TiO2粒子均易失活.SPS和XPS测试结果表明,光催化剂表面的导电类型由反应前的n型变成了失活后的p型.这主要是由于反应产物发生吸附所致.失活后的光催化剂可以通过浸洗和干燥再生. 相似文献