Production of a Platinum-Free Chelate Catalyst Material as an Intermediate Product, and Further Processing Thereof to Obtain an Electrocatalytic Coating as a Final Product
A method for preparing a platinum-free chelate catalyst material as an intermediate product for selective electrocatalytic reduction of oxygen includes performing a low-temperature plasma treatment on a powdery form of the transition-metal chelate in a plasma reactor chamber having an inert plasma gas disposed therein. A plasma power, a plasma gas pressure, a plasma initialization and a treatment time of the low-temperature plasma treatment are selected so that molecules of the transition metal chelate are fragmented in the plasma and cross-link in a subsequent chemical reaction so as to form a carbon matrix and retain a basic chelate structure in a surrounding of the transition metal.
1 - 10 . (canceled)
11 : A method for preparing a platinum-free chelate catalyst material as an intermediate product for selective electrocatalytic reduction of oxygen, the catalyst material including a porous conductive carbon matrix having embedded electrochemically active centers of a transition-metal chelate, the method comprising:
performing a low-temperature plasma treatment on a powdery form of the transition-metal chelate in a plasma reactor chamber having an inert plasma gas disposed therein; and
selecting a plasma power, a plasma gas pressure, a plasma initialization and a treatment time of the low-temperature plasma treatment so that molecules of the transition metal chelate are fragmented in the plasma and cross-link in a subsequent chemical reaction so as to form the carbon matrix and retain a basic chelate structure in a surrounding of the transition metal.
12 : The method as recited in claim 12 wherein:
the gas pressure in the plasma reactor chamber is about 10 Pa;
the plasma initialization is in response to frequency excitation within a radio frequency range;
the plasma power is more than 250 W; and the treatment time is between 5 and 20 minutes.
13 : The method as recited in claim 1 further comprising providing carbon as a substrate medium for the powdery transition metal chelate.
14 : The method as recited in claim 11 wherein the transition metal chelate is CoTMPP.
15 : The method as recited in claim 11 wherein the inert plasma gas is argon.
16 : A method for making an electrocatalytic coating on a substrate for selective electrocatalytic reduction of oxygen, the coating including a platinum-free chelate catalyst material having a porous conductive carbon matrix with embedded electrochemically active centers of a transition-metal chelate, the method comprising:
performing a first low-temperature plasma treatment on a sputtering target made of the transition-metal chelate in a plasma reactor chamber having an inert plasma gas disposed therein;
selecting a plasma power, a plasma gas pressure and a plasma initialization of the first low-temperature plasma treatment so that molecules of the transition metal chelate are released and pass over into the plasma without being fragmented;
performing, in the plasma reactor chamber, a second low-temperature plasma treatment of the released unfragmented molecules of the transition metal, the plasma reactor chamber having the inert plasma gas disposed therein;
selecting a plasma power, a plasma gas pressure, a plasma initialization and a treatment time of the second low-temperature plasma treatment so that molecules of the released unfragmented molecules of the transition metal chelate are fragmented in the plasma and cross-link in a subsequent chemical reaction so as to form the carbon matrix and retain a basic chelate structure in a surrounding of the transition metal; and
performing a deposition, onto the substrate, of the platinum-free chelate catalyst material prepared in the second low-temperature plasma treatment.
17 . The method as recited in claim 16 wherein the first and the second plasma treatments are each performed at least once in alternating fashion, and further comprising protecting the sputtering target during the second plasma treatment.
18 : The method as recited in claim 16 wherein the first and the second plasma treatments are performed a plurality of times alternatingly at a frequency within a kHz to mHz range.
19 : The method as recited in claim 16 wherein the first and the second plasma treatments are performed in parallel in respective separate regions of the plasma reactor chamber.
20 : The method as recited in claim 16 wherein
the plasma gas pressure of the first plasma treatment is about 10 Pa;
the plasma initialization of the first plasma treatment is in response to frequency excitation within a radio frequency range; and
the plasma power of the first plasma treatment is less than 150 W.
21 : The method as recited in claim 16 wherein:
the plasma gas pressure of the second plasma treatment is about 10 Pa;
the plasma initialization of the second plasma treatment is in response to frequency excitation within a radio frequency range;
the plasma power of the second plasma treatment is more than 250 W; and
the treatment time of the second plasma treatment is between 5 and 20 minutes.
22 : The method as recited in claim 16 wherein the substrate is made of carbon.
23 : The method as recited in claim 16 wherein the transition metal chelate is CoTMPP.
24 : The method as recited in claim 16 wherein the inert plasma gas is argon.
25 : The method as recited in claim 16 further comprising disposing the substrate within the plasma of the second low temperature plasma treatment.
26 : The method as recited in claim 16 wherein the performing of the first and second low-temperature plasma treatments are performed as part of an automated in-line process.
27 : A method for making an electrocatalytic coating on a substrate, the coating including a platinum-free chelate catalyst material having a porous conductive carbon matrix with embedded electrochemically active centers of a transition-metal chelate, the method comprising:
performing a first low-temperature plasma treatment on a sputtering target made of the transition-metal chelate in a first plasma reactor region having an inert plasma gas disposed therein;
selecting a plasma power, a plasma gas pressure and a plasma initialization of the first low-temperature plasma treatment so that molecules of the transition metal chelate are released and pass over into the plasma without being fragmented;
performing, in a second plasma reactor region separate from the first plasma reactor region, a second low-temperature plasma treatment of the released unfragmented molecules of the transition metal, the plasma reactor region having the inert plasma gas disposed therein;
selecting a plasma power, a plasma gas pressure, a plasma initialization and a treatment time of the second low-temperature plasma treatment so that molecules of the transition metal chelate are fragmented in the plasma and cross-link in a subsequent chemical reaction in such a way that the carbon matrix is formed and a basic chelate structure is retained in a surrounding of the transition metal; and
performing a deposition, onto the substrate, of the platinum-free chelate catalyst material prepared in the second low-temperature plasma treatment.
28 : The method as recited in claim 27 wherein
the plasma gas pressure of the first plasma treatment is about 10 Pa;
the plasma initialization of the first plasma treatment is in response to frequency excitation within a radio frequency range; and
the plasma power of the first plasma treatment is less than 150 W.
29 : The method as recited in claim 27 wherein:
the plasma gas pressure of the second plasma treatment is about 10 Pa;
the plasma initialization of the second plasma treatment is in response to frequency excitation within a radio frequency range;
the plasma power of the second plasma treatment is more than 250 W; and
the treatment time of the second plasma treatment is between 5 and 20 minutes.
30 : The method as recited in claim 27 wherein the first and the second plasma treatments are performed a plurality of times alternatingly at a frequency within a kHz to mHz range.