The use of fossil fuels for energy production is accompanied by carbon dioxide release into the environment causing catastrophic climate changes. Meanwhile, replacing fossil fuels with carbon-free nuclear energy has the potential to release radioactive iodine during nuclear waste processing and in case of a nuclear accident. Therefore, developing efficient adsorbents for carbon dioxide and iodine capture is of great importance. Two nitrogen-rich porous polymers (NRPPs) derived from 4-bis-(2,4-diamino-1,3,5-triazine)-benzene building block were prepared and tested for use in CO and I capture. Copolymerization of 1,4-bis-(2,4-diamino-1,3,5-triazine)-benzene with terephthalaldehyde and 1,3,5-tris(4-formylphenyl)benzene in dimethyl sulfoxide at 180 °C afforded highly porous NRPP-1 (SA = 1579 m g) and NRPP-2 (SA = 1028 m g), respectively. The combination of high nitrogen content, π-electron conjugated structure, and microporosity makes NRPPs very effective in CO uptake and I capture. NRPPs exhibit high CO uptakes (NRPP-1, 6.1 mmol g and NRPP-2, 7.06 mmol g) at 273 K and 1.0 bar. The 7.06 mmol g CO uptake by NRPP-2 is the second highest value reported to date for porous organic polymers. According to vapor iodine uptake studies, the polymers display high capacity and rapid reversible uptake release for I (NRPP-1, 192 wt % and NRPP-2, 222 wt %). Our studies show that the green nature (metal-free) of NRPPs and their effective capture of CO and I make this class of porous materials promising for environmental remediation.

Finding alternative catalysts as a replacement for platinum in fuel cells to perform oxygen reduction reaction (ORR) is vital for the widespread use of fuel cell technology. The scarcity and high cost of platinum combined with its vulnerability to poisoning by fuel crossover greatly impede effective use of fuel cells. In this study, a simple and cost-effective synthesis using triphenylphosphine and iron(II) chloride was developed to produce highly porous P and Fe-doped carbon (PFeC, SA BET = 967 m 2 g −1 ) with Fe and P contents of 9.8 and 4.1 at. %, respectively. This synthetic route also generates Fe 2 P particles, active centers, supported on P-doped porous carbon which was found to be electrochemically active toward ORR in both alkali and acidic media. The optimized PFeC electrocatalyst has a competitive onset and half-wave potential in comparison to commercially available Pt/C (20 wt %), and it selectively reduces O 2 via a single-step 4e − reaction pathway. The PFeC electrocatalyst exhibits superior long-term stability of 90% for the duration of a 15 h chronoamperometry test and inertness toward the oxidation of methanol. The superior electrocatalytic performance is credited to the synergistic effects between the P and Fe atoms, in the form of well-defined and well-distributed nanoparticles confined in highly porous carbon nanosheets. The enhancement in electrochemical activity is also credited to the exposed active sites on the surface of the PFeC sheets and the high conductivity of the conjugated carbon backbone induced by uniform dopant disruption of the electroneutrality of carbon. The large surface area of PFeC and its well-developed porous structure increase the points of contact for adsorption and rapid transportation of the reactants and improve the overall electrocatalytic activity of PFeC.

Abstract:Commercial and Synthesized titanium di oxide (TiO 2 ) prepared by conventional sol-gel method, are modified to degrade industrial dyes. Modification is done on bare TiO 2 and TiO 2 doped with various doping agents (activated charcoal/silicon dioxide/zinc oxide), followed by thermal treatments. The role of thermal treatments and doping effects on the efficiency of TiO 2 photocatalysts are highlighted and evaluated by decoloration of Methylene Blue in aqueous solution under UV and Visible light irradiation for both systems. The results revealed that increase in calcination temperature up to optimum level enhances the photocatalytic activities of the samples and doping narrows the band gap and makes the samples visible light responsive. This study also showed that activated charcoal (AC) doped TiO 2 photocatalyst is a promising one under Visible light and is thus used to degrade other dyes such as Crystal Violet and Rhodamine B. The obtained experimental data are used to study four different kinetic models: Zero order, Pseudo first order, Parabolic diffusion and Modified Freundlich model. The best fit of the experimental data are obtained by Pseudo first order and Modified Freundlich models.

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