Highly efficient copper nitride bimetallic catalysts for electrochemical reduction of one or more carbon oxides to n-propanol and/or ethanol

Abstract

The disclosure relates to a catalyst suitable for electrochemical reduction reactions of one or more carbon oxides, comprising a nitride-doped multi-metallic material comprising a primary metal being copper and one or more secondary metals selected from silver, gold, platinum, palladium, ruthenium, iridium, osmium, and any mixture thereof, wherein the nitride-doped multi-metallic material comprises, as determined by XRD, copper, copper nitride and copper-Me alloy wherein Me is one of the secondary metals and to a gas diffusion electrode suitable for electrolysis of one or more carbon oxides comprising such a catalyst.

1 . A catalyst suitable for electrochemical reduction reactions of one or more carbon oxides, characterized in that it comprises a nitride-doped multi-metallic material comprising a primary metal being copper and one or more secondary metals selected from silver, gold, platinum, palladium, ruthenium, iridium, osmium, and any mixture thereof; and in that the nitride-doped multi-metallic material comprises, as determined by XRD, copper, copper nitride and copper-Me alloy wherein Me is one of the secondary metals. 
     
     
         2 . The catalyst according to  claim 1  is characterized in that one or more secondary metals are selected from silver, gold, and any mixture thereof. 
     
     
         3 . The catalyst according to  claim 1  is characterized in that the nitride-doped multi-metallic material comprises from 0.5 to 10.0 mol % of the one or more secondary metals based on the total molar content of copper and one or more secondary metals; with preference, from 1.0 to 10.0 mol %. 
     
     
         4 . The catalyst according to  claim 1  is characterized in that the nitride-doped multi-metallic material comprises two or more secondary metals and comprises from 0.5 to 8.0 mol % of the secondary metals based on the total molar content of copper and secondary metals; with preference 1.0 to 6.0 mol %. 
     
     
         5 . The catalyst according to  claim 1  is characterized in that the nitride-doped multi-metallic material comprises two or more secondary metals, wherein at least one of the secondary metals is silver or gold; preferably wherein at least two secondary metals are silver and gold. 
     
     
         6 . The catalyst according to  claim 1  is characterized in that the nitride-doped multi-metallic material comprises two or more secondary metals, wherein at least two secondary metals Me1 and Me2 are present in a ratio Me1/Me2 ranging from 1 to 15; preferably from 1 to 10; more preferably, from 1 to 4. 
     
     
         7 . The catalyst according to  claim 1  is characterized in that the nitride-doped multi-metallic material comprises two or more secondary metals, wherein at least two secondary metals Me1 and Me2 differ by their reduction potential wherein Mel has a reduction potential greater than Me2, and in that Me1 and Me2 are present in a ratio Me1/Me2 greater than 1; preferably greater than 2; more preferably greater than 3. 
     
     
         8 . The catalyst according to  claim 1  is characterized in that the nitride-doped multi-metallic material is a nitride-doped bimetallic material and comprises from 2.0 to 8.0 mol % of the secondary metals based on the total molar content of copper and secondary metals; with preference 3.0 to 7.0 mol %. 
     
     
         9 . The catalyst according to  claim 1  is characterized in that the nitride-doped multi-metallic material shows Cu (111) and Cu (200) facets as determined by XRD. 
     
     
         10 . The catalyst according to  claim 1  is characterized in that the nitride-doped multi-metallic material is in the form of rode-shape particles. 
     
     
         11 . The catalyst according to  claim 1  is characterized in that the nitride-doped multi-metallic material is in the form of particles that have an average diameter ranging from 20 nm to 500 nm as measured by transmission electron microscopy; preferably, ranging from 50 nm to 400 nm or from 80 to 350 nm. 
     
     
         12 . A method to produce a catalyst according to  claim 1  is characterised in that it comprises:
 a) providing copper particles; 
 b) adding of one or more secondary metals selected from silver, gold, platinum, palladium, ruthenium, and any mixture thereof, wherein said step of addition comprises a step (b1) of galvanic exchange reaction or a step (b2) of electrodeposition or both steps (b1) of galvanic exchange reaction and step (b2) of electrodeposition, to obtain a multi-metallic material comprising copper as primary metal and one or more secondary metals; 
 c) nitridation of the multi-metallic material obtained in step b) to obtain a nitride-doped multi-metallic material. 
 
     
     
         13 . The method according to  claim 12  is characterised in that the step b) is a step (b1) of galvanic exchange reaction and is performed by stirring the copper particles in an aqueous solution comprising one or more selected from chloroplatinic acid hexahydrate, ruthenium acetylacetonate, iridium acetylacetonate, osmium acetylacetonate, rhodium acetylacetonate, palladium acetylacetonate, palladium nitrate, palladium chloride, gold chloride trihydrate, silver nitrate, and any mixture thereof. In a preferred embodiment, the aqueous solution comprises gold chloride trihydrate, silver nitrate, and any mixture thereof. 
     
     
         14 . The method according to  claim 12  is characterized in that the nitride-doped multi-metallic material comprises two or more secondary metals, and in that the step b) is a step (b1) of galvanic exchange reaction comprising successive sub-steps of galvanic exchange reaction; with preference, the two or more secondary metals differ by their reduction potential and the successive sub-steps of galvanic exchange reaction are performed starting by the secondary metal having the highest reduction potential. 
     
     
         15 . The method according to  claim 12  is characterised in that the nitridation step comprises a calcination sub-step followed by a copper nitride synthesis sub-step; preferably the copper nitride synthesis sub-step is performed at a temperature ranging from 150 to 190° C. and for a time ranging from 5 to 30 hours. 
     
     
         16 . The method according to  claim 12  is characterised in that the copper particles have an average diameter ranging from 5 nm to 200 nm as measured by transmission electron microscopy; preferably, the copper particles are nanoparticles and have an average diameter ranging from 5 nm to 100 nm as measured by transmission electron microscopy. 
     
     
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