Method For Monitoring A Process For Powder-Bed Based Additive Manufacturing Of A Component And Such A System

Abstract

A gas diffusion electrode and electrolysis cells containing gas diffusion electrodes are provided. The gas diffusion electrodes include a copper-containing carrier, and first and second layers. The first layer comprising at least copper and at least one binder having hydrophilic and hydrophobic pores. The second layer comprising copper and at least one binder. The second layer present atop the carrier and the first layer atop the second layer, wherein the content of binder in the first layer is less than the binder in the second layer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a U.S. National Stage Application of International Application No. PCT / EP2016 / 067165 filed Jul. 19, 2016, which designates the United States of America, and claims priority to DE Application No. 10 2015 215 309.6 filed Aug. 11, 2015, the contents of which are hereby incorporated by reference in their entirety.FIELD OF INVENTION[0002]The present invention relates to a gas diffusion electrode preferably comprising a copper-containing carrier and a first layer comprising at least copper and at least one binder and a second layer. The (first) layer comprises hydrophilic and hydrophobic pores and / or channels. The second layer comprising copper and at least one binder, wherein the second layer is present atop the carrier and the first layer atop the second layer, wherein the content of binder in the first layer is less than in the second layer. The present invention also relates to a process for producing a gas diffusion ele...

AI Technical Summary

Benefits of technology

The patent is about the need for cathodes that can effectively convert carbon dioxide to hydrocarbons. The invention aims to provide a new catalyst concept that does not require copper deposition and can be processed to create an electrode. Additionally, the patent aims to develop selective electro-catalysts that are stable over a long period of time and can be embedded into gas diffusion electrodes that can connect to electrical contacts.

Problems solved by technology

This process, which is divided up into many component steps over time and spatially at the molecular level, is reproducible on the industrial scale only with difficulty.

However, overproduction of renewable energies is not continuously available, but at present only at periods of strong insolation and / or wind.

In spite of many efforts, it has not been possible to date to develop an electrochemical system with which CO2 could be reduced with long-term stability and in an energetically favorable manner to competitive energy sources with sufficiently high current density and acceptable yield.

However, the prior art in this regard is not yet very developed.

However, in the case of electrodes produced in this way, the selectivity of the electrode can decrease with time, which can lead to an increase in hydrogen production.

In this context, said wet method 1. can have the disadvantages mentioned hereinafter, aside from the fact that examples of gas diffusion electrodes known from the literature contain the catalyst only as an additive and consist mainly of bound conductive charcoal (for high conversions the catalyst loading should be high):

The suspensions or pastes that are usually applied by spraying or bar coating generally have long drying times, which means that continuous production with relatively large electrode areas (of industrial relevance) is not economically possible.

Excessively rapid drying leads to cracking, called “mud cracking”, within the layers applied, which makes the electrode unusable.

This process is highly solvent- or boiling point-dependent and can lead to a high reject rate of the electrodes produced, since the evaporation cannot be assured in a homogeneous manner over the entire area.

A further central disadvantage is the use of surface-active substances (surfactants) or thickeners, plasticizers, which are used for stabilization of the particle suspensions since they cannot be removed without residue by the corresponding drying phases or the thermal crosslinking process.

The embedding process 2., wherein Nafion® (perfluorosulfonic acid, PFSA) is used as binder rather than PTFE, likewise has corresponding disadvantages, since a wet-chemical method using appropriate surfactants is being employed here too.

Nafion® itself is a hydrophilic ionomer having highly acidic R—HSO3 groups which can lead to unwanted acid corrosion or partial dissolution of the metal in the case of some catalysts.

The purely hydrophilic properties of Nafion® can likewise be disadvantageous, since Nafion®, owing to its hydrophilic properties, is unsuitable for formation of hydrophobic channels that are advantageous for gas transport within a gas diffusion electrode.

However, multilayer coating processes are not very attractive for economic reasons.

Nafion®-based coating processes can additionally lead to unwanted formation of hydrogen.

Owing to the low mechanical stability, the latter method is less suitable than the above-specified one-step process.

However, reproduction experiments which are cited hereinafter as comparative examples demonstrate that the static pressing method described does not lead to stable electrodes.

The added Vulkan XC 72 was likewise found to have an adverse effect, and so it was likewise not possible to obtain any hydrocarbons.

However, in-house preliminary tests have shown that this is not appropriate to the aim.

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