The central role of electrochemistry in researches on renewable energy is well-known, but electrochemistry is commonly associated only to batteries, fuel cells and supercapacitors. However, electrodeposition and the closely-related spontaneous deposition processes may be advantageously exploited to prepare catalysts for partial and total low-temperature oxidation of various fuels and electrocatalysts for the electrolytic production of hydrogen. The (electro)catalysts whose preparation, characterization and testing is reviewed in the present communication consist of metal foams modified through the (electro)deposition of noble metal particles. Nickel and Fe-Cr-Al alloy foams are commercially available materials characterized by large surface area, efficient mass and heat transfer, and mechanical strength. Fe-Cr-Al alloys have also an outstanding resistance to hightemperature oxidation. The deposition of catalytic noble metals (e.g. Pt, Pd, Rh) may be achieved electrochemically or through spontaneous processes based on galvanic displacement reactions, occurring at open circuit, in which noble metal nuclei form on the foam surface, while the foam itself undergoes some dissolution, accompanied by surface roughening. In the materials prepared by either method, there is electrical contact between the foam support and the catalytic particles, in contrast to what happens in catalysts for gasphase oxidation reactions prepared by conventional approaches. Therefore, electrochemical methods, e.g. cyclic voltammetry, may be used for assessing the noble metal surface area, both in as-prepared samples and after their use in catalytic tests. Examples mentioned in the present communication include the low-temperature catalytic oxidation of CO and CH4 on Pd-modified Fe-Cr-Al alloy [1], the lowtemperature total combustion of methanol on Pt-modified Fe-Cr-Al foams [2], and the hydrogen evolution reaction on Pt-modified Ni foams [3].
Electrodeposition and galvanic displacement: new ro utes to 3D catalysts for clean combustion and H2 electrolytic production
Cimino S;Mancino G;Musiani M;Verlato E
2016
Abstract
The central role of electrochemistry in researches on renewable energy is well-known, but electrochemistry is commonly associated only to batteries, fuel cells and supercapacitors. However, electrodeposition and the closely-related spontaneous deposition processes may be advantageously exploited to prepare catalysts for partial and total low-temperature oxidation of various fuels and electrocatalysts for the electrolytic production of hydrogen. The (electro)catalysts whose preparation, characterization and testing is reviewed in the present communication consist of metal foams modified through the (electro)deposition of noble metal particles. Nickel and Fe-Cr-Al alloy foams are commercially available materials characterized by large surface area, efficient mass and heat transfer, and mechanical strength. Fe-Cr-Al alloys have also an outstanding resistance to hightemperature oxidation. The deposition of catalytic noble metals (e.g. Pt, Pd, Rh) may be achieved electrochemically or through spontaneous processes based on galvanic displacement reactions, occurring at open circuit, in which noble metal nuclei form on the foam surface, while the foam itself undergoes some dissolution, accompanied by surface roughening. In the materials prepared by either method, there is electrical contact between the foam support and the catalytic particles, in contrast to what happens in catalysts for gasphase oxidation reactions prepared by conventional approaches. Therefore, electrochemical methods, e.g. cyclic voltammetry, may be used for assessing the noble metal surface area, both in as-prepared samples and after their use in catalytic tests. Examples mentioned in the present communication include the low-temperature catalytic oxidation of CO and CH4 on Pd-modified Fe-Cr-Al alloy [1], the lowtemperature total combustion of methanol on Pt-modified Fe-Cr-Al foams [2], and the hydrogen evolution reaction on Pt-modified Ni foams [3].I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
