Improved performance of porphyrin-based dye sensitised solar cells by phosphinic acid surface treatment

Chemical surface treatment of porphyrin-sensitised titania films using bis-(4-methoxyphenyl) phosphinic acid after dye adsorption, results in large improvements in DSSC efficiencies which originate primarily from higher short circuit currents. The result was attributed to a positive shift in the TiO2 quasi-Fermi level with simultaneous retardation of charge recombination. High device performances have been achieved even using simplified electrolyte matrices devoid of the common additives, LiI and t-butylpyridine

Isotopic H/D exchange on graphenes. A combined experimental and theoretical study

[EN] Adsorption of H-2/D-2 on graphene (G), graphene oxide (GO), single walled carbon nanotube (SWCNT), N-doped graphene [(N)G], and a sample of active carbon (C) has led to the detection of HD, indicating dissociative chemisorption of hydrogen on the surface of the material. The amount of HD detected follows the order G > SWCNT > GO similar to (N)G similar to C, G giving about five-fold higher H-2/D-2 adsorption and HD exchange level than SWCNT and about ten-fold larger values than that of the other samples. Quantum-chemistry calculations modeling a carbon atom vacancy on a G cluster estimates an activation barrier for H-2 dissociation of ca. 84 kJ/mol for a mechanism involving under coordinated carbon atoms at the defect site.Financial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa SEV-2016-0267 and CTQ2015-69153-C2-R1) and Generalitat Valenciana (Prometeo 2013/014) is gratefully acknowledged. G. S. thanks the Scientific Division of SGAI CSIC for computing facilities.Sastre Navarro, GI.; Forneli Rubio, MA.; Almasan, V.; Parvulescu, VI.; García Gómez, H. (2017). Isotopic H/D exchange on graphenes. A combined experimental and theoretical study. Applied Catalysis A General. 547:52-59. https://doi.org/10.1016/j.apcata.2017.08.018S525954

O TURNOVER DE COLABORADORES NAS ORGANIZAÇÕES: ESTUDO DE CASO DO RECURSOS HUMANOS DE UMA USINA DE AÇÚCAR E ÁLCOOL DE SÃO JOAQUIM DA BARRA/SP

Resumo: O turnover de pessoal é um dos aspectos organizacionais a serem controlados pela empresa, visto a importância da retenção de seus talentos. Neste artigo, buscou-se, por meio de um estudo de caso e pesquisa descritiva, analisar o turnover de pessoal em uma usina afim de identificar as principais causas e consequências. O desenvolvimento deste trabalho se justifica pela importância na economia atual do capital humano e a falta da gestão em identificar que as pessoas são um capital humano dentro das organizações, seja por não conseguir mensurar todos os fatores que acompanham a motivação do colaborador, seja por não ter uma boa comunicação organizacional, ou seja, por não conseguir encontrar um profissional qualificado

A Quasi-Metal–Organic Framework Based on Cobalt for Improved Catalytic Conversion of Aquatic Pollutant 4‑Nitrophenol

To generate purposely defects that can increase the catalytic activity, cobalt-based metal–organic framework (MOF) TMU-10 has been subjected to thermal treatment under an air atmosphere at temperatures between 100 and 700 °C. This process causes partial ligand removal, generating structural defects and additional hierarchical porosity in a convenient way. The resulting materials, denoted as quasi-MOFs, were subsequently employed as catalysts for the room-temperature borohydride reduction of 4-nitrophenol (4-NP). The quasi TMU-10 framework obtained at 300 °C (QT-300) exhibits excellent catalytic performance with an apparent rate constant, activity factor, and half-life time of 2.8 × 10–2 s– 1, 282 s–1 g–1, and 24.8 s, respectively, much better values than those of parent TMU-10. Coexistence of micro and mesopores, coordinatively unsaturated cobalt nodes, tetrahedral Co­(II) ions, and Co­(III) in QT-300 are responsible for this enhanced activity. Kinetic studies in the range of 25–40 °C varying the 4-NP and BH4– concentrations agree with the Langmuir–Hinshelwood model in which both reactants are adsorbed on the catalyst surface. Reduction of 4-NP by the surface-hydrogen species is the rate-determining step