The nucleation and growth of palladium clusters supported on anatase TiO 2 (101) surface has been studied using periodic supercell models and density functional theory. The most active site for single Pd adatom on the perfect TiO 2 (101) surface is the bridge site formed by two two-coordinated oxygen (2cO) atoms at the step edge with the highest adsorption energy of 2.18 eV. On the defective surface, the effect of oxygen vacancy on Pd nucleation is not as strong as that in the Pt or Au deposition case. The shift of active sites for the Pd dimer growing to trimer on the perfect anatase TiO 2 (101) surface is observed. On both perfect and defective anatase surfaces, the adsorbed Pd 3 clusters prefer to form planar triangles and the adsorbed Pd 4 and Pd 5 clusters tend to three-dimensional structures. The nucleation and growth of Pd clusters at the anatase TiO 2 (101) surface is mainly driven by the interaction between Pd and surface atoms when the cluster size is less than four. The strength of Pd-Pd interaction turns out to control dominantly the Pd deposition process as the Pd cluster gets larger.

In this study, we design and demonstrate a novel type of self-powered UV photodetectors (PDs) using single-crystalline ZnS nanotubes (NTs) as the photodetecting layer and Ag nanowires (NWs) network as transparent electrodes. The self-powered UV PDs with asymmetric metal-semiconductor-metal (MSM) structure exhibit attractive photovoltaic characteristic at 0 V bias. Device performance analysis reveals that the as-assembled PDs have a high on/off ratio of 19173 and a fast response speed (τr = 0.09 s, τf = 0.07 s) without any external bias. These values are even higher than that of ZnS nanostructures- and ZnS heterostructure-based PDs at a large bias voltage. Besides, its UV sensivity, responsivity and detectivity at self-powered mode can reach as high as 19172, 2.56 A/W and 1.67 × 1010 cm Hz1/2 W−1, respectively. In addition, the photosensing performance of the self-powered UV PDs is studied in different ambient conditions (e.g., in air and vacuum). Moreover, a physical model based on band energy theory is proposed to explain the origin of the self-driven photoresponse characteristic in our device. The totality of the above study signifies that the present self-powered ZnS NTs-based UV nano-photodetector may have promising application in future self-powered optoelectronic devices and integrated systems.

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in Wiley InterScience (www.interscience.wiley.com).A novel magnetic microspherical catalyst support with enough mechanical strength was prepared through coating Al 2 O 3 on a magnetic core of NiFe 2 O 4 spinel ferrite using the oil drop method to synthesize magnetic Pd-supported catalyst for acetylene hydrogenation reaction. The synthesized core-shell composite Pd/Al 2 O 3 catalyst shows high surface area and pore volume as well as sufficient saturated magnetization property, characterized by powder X-ray diffraction, low-temperature N 2 adsorptiondesorption analysis, and magnetic measurements. Catalytic performance of this magnetic Pd/Al 2 O 3 catalyst was measured for acetylene hydrogenation reaction in a magnetically stabilized bed (MSB) reactor under different operation conditions. Under the optimal conditions of 353 K, 1.5 MPa and a gas hourly space velocity of 12,000 h 21 , C 2 H 2 conversion and C 2 H 4 selectivity approximated 100% and 84%, respectively, over this magnetic Pd/Al 2 O 3 catalyst in the MSB reactor, as a control over the commercial catalyst for hydrogenation reaction C 2 H 2 conversion and C 2 H 4 selectivity was near 37 and 64% under the similar conditions. Significant improvement of acetylene hydrogenation processes over this novel magnetic catalyst enlightens us a promising route to explore process intensification techniques through MSB.

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The cycling performance of Li−O 2 batteries (LOBs), which is an important parameter determining the practical use of this advanced energy technology with ultrahigh energy density, is strongly affected by the nature of the oxygen electrocatalyst. As a good oxygen electrode, it should possess good activity for both the oxygen evolution reaction and the oxygen reduction reaction and superior stability under operating conditions. During the past, oxygen electrodes for LOBs were generally fabricated by loading noble metal nanoparticles on the surface of a porous carbon support. However, the nanoparticles could easily lose contact with the carbon support during the reversible liquid−gas− solid reactions that involve lithium ions, oxygen gas, and Li 2 O 2 . Herein, we reported a novel Ru-metal−organic framework (MOF)-derived carbon composite, characterized by stereoscopic Ru nanoparticle distribution within the carbon matrix, as an alternative oxygen catalyst of LOBs, enabling superior operational stability and favorable activity. More specifically, the battery demonstrated stable charge−discharge cycling for up to 800 times (∼107 days) at a current density of 500 mA g −1 with low discharge/charge overpotentials (∼0.2/0.7 V vs Li). A mechanism of regenerative surface was further proposed to explain the excellent cycling stability of the LOBs through the use of the Ru-MOF−C catalyst. These encouraging results imply an accessible solution to address issues related to the oxygen catalyst for the realization of practical LOBs.

Vapor–liquid equilibrium (VLE) data of working fluids play a vital role in the research and development of absorption refrigeration technology. In this paper, the VLE data of two new working fluids, 1,1-difluoroethane (R152a) + N,N-dimethylformamide (DMF) and R152a + N,N-dimethylacetamide (DMAC), were measured by the static analytical method at temperatures from (293.15 to 353.15) K. The experimental results show that R152a exhibits better solubility characteristics with DMF and DMAC, and the solubility of R152a in DMAC is slightly better than that in DMF. All experimental data were correlated by the activity coefficient model of five-parameter nonrandom two liquid (NRTL). The calculated results are in essential agreement with the experimental data, and the maximum relative deviation of pressure are 3.69 % and 3.51 %, the average relative deviation of pressure are 1.60 % and 1.11 %, for binary systems R152a + DMF and R152a + DMAC, respectively.

A series of fatty acids/carbon nanotubes (CNTs) composite shape-stabilized PCMs were prepared through infiltration method by using the eutectic mixture of capric acid, lauric acid, and palmitic acid as phase change materials, multi-walled CNTs as a supporting material. Nitrogen adsorption-desorption curves and SEM images of composite shape-stabilized PCMs indicate that the eutectic mixture was effectively absorbed into the porous structure of the CNTs. DSC thermograms show that the composite fatty acids/CNTs possess good phase change behavior. And the latent heat of the sample absorbed with 80 wt% fatty acids can achieve 101.6 J g -1 in the melting process and its phase change temperatures and latent heat almost remain unchanged in 30 times of thermal cycling. Moreover, the thermal conductivity of the composite materials are significantly improved (up to 0.6661 W m -1 k -1 ) due to the addition of the highly thermal conductive CNTs.