Accelerated Polyethylene Terephthalate (PET) Enzymatic Degradation by Room Temperature Alkali Pre-treatment for Reduced Polymer Crystallinity

Polyethylene terephthalate (PET) is the most widely employed plastic for single-use applications. The use of enzymes isolated from microorganisms, such as PETase with the capacity to hydrolyze PET into its monomers, represents a promising method for its sustainable recycling. However, the accessibility of the enzyme to the hydrolysable bonds is an important challenge that needs to be addressed for effective biodegradation of postconsumer PET. Here, we combined an alkali pre-treatment (25 °C) with PETase incubation (30 °C) with post-consumed PET bottles. The pre-treatment modifies the surface of the plastic and decreases its crystallinity enabling the access of the enzyme to the hydrolysable chemical bonds. When the alkali pre-treatment is incorporated into the enzymatic process the degradation yields increase more than one order of magnitude reaching values comparable to those obtained during heating/cooling cycles. Our results show energetic advantages over other reported pre-treatments and open new avenues for sustainable PET recycling.Funding for open access charge: CRUE-Universitat Jaume

Highly porous Ti-Ni anodes for electrochemical oxidations

Treball Final de Màster Universitari en Química Sostenible (Pla de 2015). Codi: SJE020. Curs acadèmic: 2019/2020The hydrogen rising economy is demanding an active and durable electrocatalysts based on low-cost, earth abundant materials for water electrolysis. Oxygen electrochemistry plays a key role in renewable energy technologies, but the slow kinetics of oxygen evolution reaction limit the performance and commercialization such as devices. Nonetheless, most of the previous work has been focus on precious metals and there are no guidelines for the choice of oxides as evolving oxygen electrodes. Up to now, iridium dioxide and ruthenium dioxide are the state-of-theart oxygen evolution reaction electrocatalysts with low overpotential and Tafel slope. This work describes a general method to obtain highly porous electrodes and their use as dimensionally stable anodes for the O2 evolution reaction (OER). By using a powder metallurgy based process, where metallic titanium and nickel powders are pressed and thermally treated, we obtain electrodes that benefit from a 1000-fold increase in the electrochemical surface area (ECSA). In addition, active catalytic species for water oxidation (i.e. NiOOH) are generated during the processing converting these electrodes as ideal candidates for evaluation in oxidation reactions. Excellent OER performance is obtained with overpotentials below 270 mV at 10 mA cm−2, exceeding those of commercially available alternatives. The current work paves the way for a generic method that will be extended to other electrochemical reactions

Synthesis of metal oxide catalysts for water splitting

Treball Final de Grau en Química. Codi: QU0943. Curs acadèmic: 2018/2019The hydrogen rising economy is demanding an active and durable electrocatalysts based on low-cost, earth abundant materials for water electrolysis. Oxygen electrochemistry plays a key role in renewable energy technologies, but the slow kinetics of oxygen evolution reaction limit the performance and commercialization such as devices. Nonetheless, most of the previous work has been focus on precious metals and there are no guidelines for the choice of oxides as evolving oxygen electrodes. Up to now, iridium dioxide and ruthenium dioxide are the state-of-the-art oxygen evolution reaction electrocatalysts with low overpotential and Tafel slope. In this work, has been focused on the combination of an electrically conductive titanium powder matrix, titanium oxide because the strong oxidizing power of its holes, high photostability and redox selectivity and nickel due to its excellent performance and stability for the evolution of oxygen. In addition, the study of the role of metal/metal oxide couple required for the evolution of oxygen

Highly porous Ti–Ni anodes for electrochemical oxidations

This work describes a general method to obtain highly porous electrodes and their use as dimensionally stable anodes for the O2 evolution reaction (OER). By using a powder metallurgy based process, where metallic titanium and nickel powders are pressed and thermally treated to form “brown compacts”, we obtain electrodes that benefit from a 1000-fold increase in the electrochemical surface area (ECSA). In addition, active catalytic species for water oxidation (i.e. NiOOH) are generated during the processing converting these electrodes as ideal candidates for evaluation in oxidation reactions. Excellent OER performance is obtained with overpotentials below 270 mV at 10 mA cm−2, exceeding those of commercially available alternatives. The current work paves the way for a generic method that will be extended to other electrochemical reactions