摘要：Hierarchical porous TiO2 nanopills were synthesized using a titanium metal-organic framework MIL-12...Hierarchical porous TiO2 nanopills were synthesized using a titanium metal-organic framework MIL-125（Ti） as precursor. The as-synthesized TiO2 nanopills owned a large specific surface area of 102 m2/g and unique porous structure. Furthermore, the obtained TiO2 nanopills were applied as anode materials for Na-ion batteries for the first time. The as-synthesized TiO2 nanopills achieved a high discharge capacity of 196.4 m Ah/g at a current density of 0.1 A/g. A discharge capacity of 115.9 m Ah/g was obtained at a high current density of 0.5 A/g and the capacity retention was remained as high as 90% even after 3000 cycles. The excellent electrochemical performance can be attributed to its unique hierarchical porous feature.显示全部
摘要：Nanostructured metal oxides derived from metal organic frameworks have been shown to be promising m...Nanostructured metal oxides derived from metal organic frameworks have been shown to be promising materials for application in high energy density lithium ion batteries. In this work, porous nanostructured ZnCo2O4 and Co3O4 were synthesized by a facile and cost-effective approach via the calcination of MOF-74 precursors and tested as anode materials for lithium ion batteries. Compared with Co3O4, the electrochemical properties of the obtained porous nanostructured ZnCo2O4 exhibit higher specific capacity, more excellent cycling stability and better rate capability. It demonstrates a reversible capacity of 1243.2 m Ah/g after 80 cycles at 100 m A/g and an excellent rate performance with high average discharge specific capacities of 1586.8, 994.6, 759.6 and 509.2 m Ah/g at 200, 400, 600 and 800 m A/g, respectively.The satisfactory electrochemical performances suggest that this porous nanostructured ZnCo2O4 is potentially promising for application as an efficient anode material for lithium ion batteries.显示全部
摘要：The morphology effect of Zr-doped CeO2 was studied in terms of their activities in the selective ox...The morphology effect of Zr-doped CeO2 was studied in terms of their activities in the selective oxidation of styrene to styrene oxide using tert-butyl hydroperoxide as the oxidant. In the present work, Zrdoped CeO2 nanorods exhibited the highest catalytic performance（yield of styrene oxide and TOF value）followed by nanoparticles and nanocubes. For the Zr-doped CeO2 nanorods, the apparent activation energy is 56.3 k J/mol, which is much lower than the values of catalysts supported on nanoparticles and nanocubes（73.3 and 93.4 k J/mol）. The high resolution transmission electron microscopy results indicated that（100） and（110） crystal planes are predominantly exposed for Zr-doped CeO2 nanorods while（100）and（111） for nanocubes,（111） for nanoparticles. The remarkably increased catalytic activity of the Zrdoped CeO2 nanorods is mainly attributed to the higher percentage of Ce3+species and more oxygen vacancies, which are associated with their exposed（100） and（110） crystal planes. Furthermore, recycling studies proved that the heterogeneous Zr-doped CeO2 nanorods did not lose its initial high catalytic activity after five successive recycles.显示全部
摘要：SAPO-11 molecular sieves were synthesized using silica sol, hydrophilic fumed silica, and tetraethy...SAPO-11 molecular sieves were synthesized using silica sol, hydrophilic fumed silica, and tetraethyl orthosilicate（TEOS） as silicon precursors. Their physicochemical properties were characterized using XRD,SEM, nitrogen adsorption-desorption, Py-IR, NH3-TPD, EDS, and 27Al,31P,29Si MAS NMR techniques. The catalytic performance was assessed in the hydroisomerization of n-octane. The results showed that the silicon precursors influenced the physicochemical properties and catalytic performance of SAPO-11. SAPO-11 synthesized using hydrophilic fumed silica as silicon precursor showed higher silicon distribution and had more medium acid sites. SAPO-11 synthesized using TEOS as silicon precursor had more silicon content, but more silicon islands formed in its framework. The depolymerization of silicon precursors might affect the silicon content and distribution in SAPO-11. In the hydroisomerization of n-octane, the catalytic activity strongly depended on the number of medium acid sites instead of the number of total acid sites.SAPO-11 synthesized using hydrophilic fumed silica as silicon precursor exhibited higher catalytic activity than the other samples because it has more medium acid sites.显示全部
摘要：The design of cost-effective, highly active catalysts for hydrogen energy production is a vital ele...The design of cost-effective, highly active catalysts for hydrogen energy production is a vital element in the societal pursuit of sustainable energy. Water electrolysis is one of the most convenient processes to produce high purity hydrogen. Cobalt-based catalysts are well-known electrocatalysts for oxygen evolution reaction（OER）. In this article, all these merits indicate that the present cobalt nanocomposite is a promising electrocatalyst for OER. C–Co3O4-nanorods catalyst with nanorod structure was synthesized by hydrothermal treatment of CoCl2·6H2O/dextrose/urea mixture at 180 °C for 18 h and then calcined at400 °C for 3.5 h. The role of dextrose percentage in solution to achieve the uniform coating of carbon on the surface of Co3O4-nanorods has been demonstrated. The prepared materials were characterized by X-ray diffraction（XRD）, X-ray photoelectron spectrum（XPS）, field emission scanning electron microscopy（FE-SEM）, high-resolution transmission electron microscopy（HR-TEM）, and Brunauer–Emmett–Teller instrument（BET）. Due to its unique morphology, the C–Co3O4-nanorods catalyst exhibited better activity than Co3O4-microplates catalyst for OER in 1 M KOH aqueous solution. The results showed a highly efficient, scalable, and low-cost method for developing highly active and stable OER electrocatalysts in alkaline solution.显示全部
摘要：Here, Pd Ru nanoparticle networks（NPNs） with various compositions were synthesized through an ine...Here, Pd Ru nanoparticle networks（NPNs） with various compositions were synthesized through an inexpensive method in water as a green solvent, at different ratios of the H2PdCl4 and RuCl3 precursors. This is a fast, room temperature and surfactant free strategy which is able to form high surface area metal nanosponges with a three-dimensional（3D） porous structure. The structure of as-prepared nanosponges was characterized using the techniques of field emission scanning electron microscopy（FESEM）, energy dispersive spectroscopy（EDS） and cyclic voltammetry（CV）. Then, the electrocatalytic activities of Pd Ru NPNs towards formic acid oxidation were examined by electrochemical measurements including CV,chronoamperometry, and electrochemical impedance spectroscopy（EIS）. Based on studies, it was found that the current density of formic acid oxidation（FAO） is strongly dependent on the composition of Pd Ru NPNs. The best performance was realized for Pd4Ru1 NPNs compared to monometallic Pd counterpart and other bimetallic NPNs which might be ascribed to the role of Ru in the decrease of CO adsorption strength on the catalyst and consequently the priority of formic acid oxidation through the direct pathway. The Pd4Ru1 NPNs also showed the maximum current density and stability in chronoamperometric measurements. In addition, comparative studies were performed between as-prepared NPNs and CNTs-supported Pd nanoparticles（Pd NPs/CNTs）. The present results demonstrated the unique structural advantages of NPNs compared to individual Pd NPs supported on the CNT which leads to the promising performance of NPNs as supportless catalysts for the oxidation of formic acid.显示全部
摘要：Nitrogen doped carbons are an important family of materials with ideal activity for oxygen reductio...Nitrogen doped carbons are an important family of materials with ideal activity for oxygen reduction reaction(ORR). It is always interesting to search functional carbons with high heteroatom contents and desirable structure for ORR. Within this study, the surface modification of carbon nanotubes(CNTs) via hydrothermal carbonization(HTC) technique in the presence of glucose and urea was reported, where the surface of CNTs is successfully coated by nitrogen containing hydrothermal carbon layers. The resulting composite combines both advantages of the outstanding electrical conductivity of CNTs and the effective ORR active sites provided by doped nitrogen in the HTC carbon layers. By controlling the ratio of glucose and urea, the nitrogen contents coated on the surface of CNTs can reach up to 1.7 wt%. The resulting materials show outstanding electrochemical activity towards ORR in alkaline electrolyte, making it one of the valuable metal-free electrode materials and a competent alternative to the state-of-the-art Pt/C catalyst.显示全部
摘要：(La1-xMgx)2(Ni0.8Co0.2)7（x = 0.125, 0.25, 0.5） alloys were synthesized from the sintered mixture ...(La1-xMgx)2(Ni0.8Co0.2)7（x = 0.125, 0.25, 0.5） alloys were synthesized from the sintered mixture of La2O3+ Ni O + Co O + Mg O in the molten CaCl2 electrolyte at 750 °C and the electrochemical hydrogen storage capacities of the synthesized alloys were measured. Non-hygroscopic LaNiO3 phase formed during sintering（at 1200 °C for 2 h） as a result of the reaction of hygroscopic La2O3 with NiO. Another sinter product was Mg0.4Ni0.6O phase. Both mixed oxide sinter products facilitated the La-Ni and Mg-Ni phase formations. X-ray diffraction peaks indicated that the first stable phase appeared in the alloy structure was LaNi5 which formed upon reduction of La2NiO4 phase. Increase in Mg content caused formation of La1.5Mg0.5Ni7 phase in the alloy structure and the presence of this phase improved the hydrogen storage performance of the electrodes. It was observed that(La1-xMgx)2(Ni0.8Co0.2)7（x = 0.125, 0.25, 0.5） alloys have promising discharge capacities change between 319 m Ah/g and 379 m Ah/g depending on the alloy Mg content.显示全部
摘要：Ultrathin free-standing electrospun carbon nanofiber web（ECNFW） used for the electrodes of the va...Ultrathin free-standing electrospun carbon nanofiber web（ECNFW） used for the electrodes of the vanadium flow battery（VFB） has been fabricated by the electrospinning technique followed by the carbonization process in this study to reduce the ohmic polarization of the VFB. The microstructure, surface chemistry and electrochemical performance of ECNFW carbonized at various temperatures from 800 to 1400 °C have been investigated. The results show that ECNFW carbonized at 1100 °C exhibits the highest electrocatalytic activity toward the V2+/V3+redox reaction, and its electrocatalytic activity decreases along with the increase of carbonization temperature due to the drooping of the surface functional groups.While for the VO2+/VO2+redox couple, the electrocatalytic activity of ECNFW carbonized above 1100 °C barely changes as the carbonization temperature rises. It indicates that the surface functional groups could function as the reaction sites for the V2+/V3+redox couple, but have not any catalytic effect for the VO2+/VO2+redox couple. And the single cell test result suggests that ECNFW carbonized at 1100 °C is a promising material as the VFB electrode and the VFB with ECNFW electrodes obtains a super low internal resistance of 250 mΩ cm2.显示全部
摘要：Formic acid photodegradation is one of the most important reactions in organic pollution control, a...Formic acid photodegradation is one of the most important reactions in organic pollution control, and helps to improve the hydrogen generation efficiency in titanium dioxide catalyzed water photodecomposition. Based on density functional theory and Reax FF molecular dynamics, the adsorption, diffusion and activation of formic acid on the different anatase TiO2（101）,（001）,（010） surfaces are investigated.The result shows that the adsorption of COOH on anatase TiO2 surface shrinks the energy gap between the dehydrogenation intermediate COOH and HCOO. On the anatase TiO2（101） surface, the formic acid breaks the O–H bond at the first step with activation energy 0.24 eV, and the consequent break of α-H become much easier with activation energy 0.77 eV. The dissociation of α-H is the determination step of the HCOOH decomposition.显示全部
