Co-generation of Ammonia and H2 from H2O Vapor and N2 Using a Membrane Electrode Assembly

The direct electrochemical synthesis of NH3 from nitrogen and water vapor without the use of a fossil carbon source is highly desired. This synthesis is a viable option to store energy and produce fertilizer precursors. Here, a new Pt-free membrane electrode assembly is presented. An electrochemical membrane reactor demonstrates the feasibility of co-generating NH3 and H2 directly from nitrogen and water vapor at ambient conditions. An unprecedented high NH3-specific current efficiency of up to 27.5% using Ti as cathodic catalyst is reported. The co-generation can be tuned by the balance of process parameters. © 2019 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Deciphering the Exceptional Performance of NiFe Hydroxide for Oxygen Evolution Reaction in Anion Exchange Membrane Electrolyzer

Hydrogen production via water electrolysis with renewable electricity as input will be crucial for the coming defossilized energy age. Herein, we report an anion exchange membrane electrolyzer using Fe-doped Ni hydroxide as anode catalyst that is on par with proton exchange membrane electrolyzers in terms of performance, 2 A cm-2 at 2.046 V and 50 °C. We found that Fe-doping stabilizes the alfa-Ni(OH)2 phase which is key to ensure the fast Ni(OH)2/NiOOH redox transition and the subsequent fast reaction between Ni3+/4+ and the electrolyte (OH-), resulting in the excellent oxygen evolution reaction activity of Fe-doped Ni hydroxide. Spin-polarized DFT+U computations reveal that the local arrangement of Fe3+ with Ni3+/4+ plays a crucial role in enabling the high OER activity on (001) facet of this anode catalyst

Sulfonated poly(ether ether ketone) based composite membranes for nanofiltration of acidic and alkaline media

Several thin film composite nanofiltration membranes have been prepared by spin coating a sulfonated poly(ether ether ketone) solution on a polyethersulfone support, followed by thermal treatment. The most optimal developed nanofiltration membrane shows a clean water permeance of ∼4.5 L m−2 h−1 bar−1 and a molecular weight cut off (MWCO) of ∼500 g mol−1. No irreversible changes in membrane performance have been observed after prolonged exposure (up to several weeks) of this membrane to solutions with a pH in the range 0–14. Compared to Desal-5-DK, the developed membrane displays a similar water permeance and a higher NaCl retention. In comparison to commercially available pH stable membranes, MPF-34 and NP030P, it reveals a higher water permeance. Permeance and MWCO analysis at varying pH indicates that charge effects induce reversible changes in the membrane materials properties. Especially at strongly alkaline conditions the developed membrane appears to be more open

Electrochemical conversion of CO2 to methanol – towards development of a 2 kW stack

CO2 can be considered as one of the main drivers for the anthropogenic climate change and political restriction on its emission is increasing. Around 97 million tons are emitted daily [1]. Hence, use of renewable energy sources for production of fuels and chemicals based on CO2 is a profitable and green business strategy, explaining the immense research that has begun in this field. In an electrochemical process CO2 is reduced on the cathode leading to a large product diversity [2] . So far, high selectivity towards methanol has only been demonstrated at rather low current densities and for short time [3–5]. Main challenges in this process are the concurrent hydrogen evolution reaction caused by the inevitable presence of water, slow kinetics, the reduction of oxides on the catalyst surface which function as the catalytically active species, and crossover of methanol to the anode side. The aim of the LOTER.CO2M project, funded within the Horizon 2020 program by the European Union, is to design and realize an improved process consisting of low-cost electrocatalysts, smart membrane design, and optimized stack operation. Using selective catalyst materials in an MEA are with gasphase reaction a high selectivita of > 90 % and conversion rate of > 60% is targeted. With the help of this poster we would like to present and discuss the activities in the LOTER.CO2M project,Smart design of catalyst, membrane development to avoid methanol crossover and operation of the stack to guarantee a gas phase reaction. should lead to a demonstrator of scale up 2 kW running at RWE