N-Doped CMK-3 carbons supporting palladium nanoparticles as catalysts for hydrodechlorination

The effect of nitrogen doping of a carbon support on the activity of Pd catalysts in the hydrodechlorination of 4-chlorophenol in water has been studied. Highly mesoporous CMK-3 carbons have been synthesized by infiltration of a commercial resol resin into SBA-15 silica followed by pyrolysis at 700 °C and removal of the template with NaOH. Nitrogen doping was achieved by infiltrating 1,10-phenantroline together with the resin. Equivalent porous texture and Pd nanoparticles size were obtained for the catalysts based on undoped and nitrogen-doped CMK-3 carbons. The catalysts allowed fast 4-chlorophenol hydrodechlorination with exclusive selectivity to phenol. A higher activity was observed at 30 °C for the catalyst with the N-doped support (76-81 mmol·gPd-1·min-1), showing the beneficial effect of nitrogen doping of the carbon supports. The different behavior was also evidenced by the activation energies calculated for the catalysts with undoped (53 kJ·mol-1) and N-doped CMK-3 carbon (36 kJ·mol-1) in the 30 - 70 °C temperature rangeThe authors thank Hexion Speciality Chemicals Iberica S.A. for providing the resol resin Bakelite PF9934 FL and MINECO for providing financial support (CTQ2012-32821, CTQ2015-65491_R) and for the Ph.D. (BES-2013-066085) grant to C.R.-

Platinum and N-doped carbon nanostructures as catalysts in hydrodechlorination reactions

Novel Pt catalysts supported on undoped and N-doped (1% N, w) carbons with well interconnected and nanostructured mesoporosity (Vmesopore = 0.65 cm3 g−1, SEXT = 730 m2 g−1) were prepared and tested in the hydrodechlorination of 4-chlorophenol in water at 30–70 °C. The growth of Pt nanoparticles was achieved using incipient wetness impregnation and a modified colloidal synthesis. Total conversion of 4chlorophenol and 100% selectivity to cyclohexanol was achieved. The remarkable activity in the hydrogenation of the phenol resulting from hydrodechlorination has not been reported before with Pt catalysts and it is of high interest because it maximizes detoxification. When the Pt NPs were synthesized by incipient wetness impregnation some influence of the N-doping of the support was observed in the size and electronic state of the NPs. However, highly reproducible Pt NPs were prepared by in situ colloidal synthesis regardless the nature of the support. In this last case similar activity was observed for the catalysts with undoped and N-doped carbon support, although the activity increased more with temperature for the later. Apparent activation energies of 15–25 kJ mol−1 were obtained for the disappearance of 4-chlorophenolThe authors also thank to Hexion Speciality Chemicals Iberica S.A. for providing the resol resin Bakelite®PF9934 FL. The authors thank financial support (CTQ2012-32821, CTQ2015-65491_R) and C. Ruiz-García for PhD grant (BES-2013-066085) to MINEC

Improving the activity in hydrodechlorination of Pd/C catalysts by nitrogen doping of activated carbon supports

Aqueous phase 4-chlorophenol hydrodechlorination reaction was used to study the effect of N-doping of activated carbon support on the catalytic activity of Pd catalysts. Activated carbon was doped using pyridine and 1,10-phenantroline, reaching nitrogen contents of 0.42-1.22 and 1.35-4.19 % (w), respectively. All catalysts (0.75 % Pd w, carbon basis) showed relatively large Pd nanoparticles (35-55nm), but they exhibited fast and complete 4-chlorophenol disappearance in batch experiments. In runs at 30°C 4-chlorophenol disappearance was mainly ascribed to hydrodechlorination, although N-doping of the support also increased adsorption. Catalysts with supports doped with pyridine yielded higher 4-chlorophenol disappearance rate in spite of lower bulk nitrogen content, however they showed higher concentration of nitrogen species at the external surface and lower loss of surface area during the doping. 4-chlorophenol disappearance rate was boosted at 60°C, with minor differences between catalysts with undoped and N-doped supports, but generation of cyclohexanone was only observed for the ones with doped support. Phenol generation simultaneous to 4-chlorophenol disappearance was observed with all the catalysts. However, subsequent hydrogenation to cyclohexanone ocurred only with the catalysts supported on N-doped activated carbonThe authors greatly appreciate the financial support of this research from the Spanish Ministry of Economy and Competitiveness through the project CTQ2012-3282

Exploration of the treatment of fish-canning industry effluents by aqueous-phase reforming using Pt/C catalysts

In the current work, an exploratory study on the application of catalytic aqueous phase reforming (APR) to the treatment of fish-canning wastewater was performed for the first time. Pt/C (3%, w) catalysts were supported on different commercial carbon supports (two activated carbons and a carbon black) and tested in the APR of tuna-cooking wastewater. The effect of the supports and the reaction systems (batch vs. semi-continuous) on the performance of the catalysts was tested. The stability of the catalysts upon 3 successive reuse cycles was checked. TOC and COD removal ranged within 45-60%, which was ascribed to adsorption on the supports, hydrothermal carbonization and APR. The percentage of valuable gases (H2 and alkanes) reached up to 18% of the gas production showing the potential of APR for the valorization and treatment of wastewater. The production of gases is affected by the high chloride, acetate and phosphate concentrations, which may provoke catalyst deactivation. The use of a catalyst with a basic support significantly increased the production of gases and the H2 percentage in the gas fraction. Gas production was higher in semi-continuous compared to batch operation, maybe because the withdrawn gas displaces the reaction towards the products. The percentage of alkanes in the gas phase decreased upon successive catalyst reuse cycles at the expense of H2, which is probably due to sintering of Pt nanoparticles with the corresponding decrease of the number of low-coordinated Pt sites promoting methanation reactionsThe authors greatly appreciate financial support from Spanish MINECO (CTQ2015-65491-R). A. S. Oliveira thanks the Spanish MINECO for a research grant (BES-2016-077244

The Dynamics of Nestedness Predicts the Evolution of Industrial Ecosystems

In economic systems, the mix of products that countries make or export has been shown to be a strong leading indicator of economic growth. Hence, methods to characterize and predict the structure of the network connecting countries to the products that they export are relevant for understanding the dynamics of economic development. Here we study the presence and absence of industries at the global and national levels and show that these networks are significantly nested. This means that the less filled rows and columns of these networks' adjacency matrices tend to be subsets of the fuller rows and columns. Moreover, we show that nestedness remains relatively stable as the matrices become more filled over time and that this occurs because of a bias for industries that deviate from the networks' nestedness to disappear, and a bias for the missing industries that reduce nestedness to appear. This makes the appearance and disappearance of individual industries in each location predictable. We interpret the high level of nestedness observed in these networks in the context of the neutral model of development introduced by Hidalgo and Hausmann (2009). We show that, for the observed fills, the model can reproduce the high level of nestedness observed in these networks only when we assume a high level of heterogeneity in the distribution of capabilities available in countries and required by products. In the context of the neutral model, this implies that the high level of nestedness observed in these economic networks emerges as a combination of both, the complementarity of inputs and heterogeneity in the number of capabilities available in countries and required by products. The stability of nestedness in industrial ecosystems, and the predictability implied by it, demonstrates the importance of the study of network properties in the evolution of economic networks.Comment: 26 page

Efficacy of Neoadjuvant Carboplatin plus Docetaxel in Triple-Negative Breast Cancer: Combined Analysis of Two Cohorts

Recent studies demonstrate that addition of neoadjuvant (NA) carboplatin (Cb) to anthracycline/taxane chemotherapy improves pathological complete response (pCR) in triple negative breast cancer (TNBC). Effectiveness of anthracycline-free, platinum combinations in TNBC is not well known. Here we report efficacy of NA carboplatin + docetaxel (CbD) in TNBC

Catalytic membrane reactor based on Pd-Sn supported on nanocarbons for the reduction of nitrate in water

This work studies the reduction of NO3- in water using a catalytic membrane reactor in flow-through configuration (FTCMR) for enhanced control of H2 availability and generation of NH4+. The catalytic membrane was prepared with metal catalysts supported on carbon materials with different structural and physicochemical properties (graphite, carbon nanofibers, reduced graphene oxide, activated carbon and carbon black). The catalysts were firstly tested in a batch reactor for screening and assessing influence of regime control on activity and selectivity. Pd-Sn catalysts showed higher production of NH4+ under chemical control than Pd-Cu ones, but equivalent performance was reached for Pd-Sn supported on carbon nanofibers and carbon black in conditions of H2 mass transfer control. Catalytic membranes were prepared with Pd-Sn catalyst according to higher impact of H2 availability in NH4+ generation. FTCMR was less selective to NH4+ compared to the batch reactor due to better control of H2 mass transfer. Reduction of NH4+ generation was achieved at the expense of activity due to lower availability of H2. However, membranes based on Pd-Sn supported on carbon nanofibers and carbon black were able to operate at higher H2 concentration with low selectivity to NH4+, making possible the use of membrane reactors at advantageous conditionsThe authors greatly appreciate the support from Spanish Agencia Estatal de Investigacion ´ (AEI, RTI2018–098431-BI00). Adrian ´ Marí thanks the Spanish AEI for a research grant (PRE-2019–088601