Title of Invention	AN ELECTRODE BASED ON RU-POLYOXOMETALATE FOR A SUPERCAPACITOR
Abstract	A. method of manufacture of an electrode based on Ru-polyoxometalate for a supercapacitor comprising the steps of impregnation of the ruthenium metal precursor, namely, aqueous solution of RuCl3xHaO on the conductive carbon support, namely, Vulcan XC72R; preparation of reducing agent from poiyoxometalate solution; reduction of the impregnated metal on carbon support obtained into its metallic oxidation state; separating the unadsorbed poiyoxometalate; drying the sample at room temperature; dispersing the electrode material, water; placing the electrode material from the above dispersion obtained on glassy carbon electrode; drying the electrode material obtained; placing a nation solution as a binder on the electrode so obtained.

Title of Invention

AN ELECTRODE BASED ON RU-POLYOXOMETALATE FOR A SUPERCAPACITOR

Abstract

A. method of manufacture of an electrode based on Ru-polyoxometalate for a supercapacitor comprising the steps of impregnation of the ruthenium metal precursor, namely, aqueous solution of RuCl3xHaO on the conductive carbon support, namely, Vulcan XC72R; preparation of reducing agent from poiyoxometalate solution; reduction of the impregnated metal on carbon support obtained into its metallic oxidation state; separating the unadsorbed poiyoxometalate; drying the sample at room temperature; dispersing the electrode material, water; placing the electrode material from the above dispersion obtained on glassy carbon electrode; drying the electrode material obtained; placing a nation solution as a binder on the electrode so obtained.

Full Text	1 ) Reports show that ruthenium oxide is one of the most promising materials^ for supercapaeitors owing to high specific capacitance and highly electrochemical reversibility. However, improvement of the utilization of Ru02.nH20 is the major issue for its practical use due to its high cost. We have adopted polyoxometalates as reducing agent to prepare nanoparticulate ruthenium on carbon supercapacitor material. The excellent redox property and high dispersion of charge by polyoxometalates has motivated us to employ them to produce ruthenium nanoparticles. During this process, polyoxometalates duo to their high adsorption capability, get adsorbed onto the material and thereby stabilize the ruthenium nanoparticles on carbon support. This invention proposes ruthenium nanoparticles stabilized by polyoxometalate on carbon based electrode to increase the performance of the electrochemical capacitor. This invention further proposes manufacture of highly dispersed ruthenium nanoparticles on carbon support to increase the effective utilization of active material. In this invention polyoxometalate performs the diverse roles of reducing agent as well as stabilizing agent In this invention the supercapacitor electrode has a high specific capacitance with low loading of ruthenium weight percentage in the electrode material in the form nanoparticles along with polyoxometalate supported on carbon. Preferably, the electrode comprises 10, 20 and 40% by weight of ruthenium nanoparticles on conductive carbon. This invention increases the specific capacitance of the conductive carbon Used to considerably high values by modifying it with ruthenium nanoparticles stabilized polyoxometaiates. The method of manufacture of an electrode based on Ru-polyoxometalate for a supercapacitor, according to this invention, comprises the steps of impregnation of the ruthenium metal precursor, namely, aqueous solution of RuCl3.xH20 on the conductive carbon support, namely, Vulcan XC72R; preparation of reducing agent from polyoxometalate solution; reduction of the impregnated metal on carbon support obtained into its metallic oxidation state; separating the unadsorbed polyoxometalate; drying the sample at room temperature; dispersing the electrode material in water; placing electrode material from the above dispersion obtained on glassy carbon electrode; drying the electrode material obtained; placing nafion solution as a binder on the electrode so obtained. In the preceding paragraph, the following steps are preferably carried out: The preparation of reducing agent from polyoxometalate solution is carried out by addition of Zn metal powder. The reduction of the impregnated metal on carbon support obtained into its metallic oxidation state is carried out by the addition of reduced polyoxometalate solution and simultaneous irradiation with microwave radiation by placing the vessel in a domestic microwave oven operating at a frequency of 2450 MHz (power 700W) for 1 minute. The unadsorbed polyoxometalate is separated by washing with water and ethanol and centrifuging the material at a speed of 10,000 rps. The sample is dried at room temperature under vacuum for 12 h. 10 mg of the electrode material is dispersed in 200 ul water. 10 ul of electrode material from the dispersion is placed on glassy carbon electrode (Area = 0.07 cm2). The electrode material obtained is dried at 70° C in a hot air oven. 5 ul of nation solution (10% solution in methanol) is placed on the electrode as a binder. Example: 1 Carbon Black: (Vulcan XC-72R) with specific surface area (BET) of 250 m2g_1 was used as the carbon support. Specific amounts of ruthenium (III) chloride hydrate (lOmM) was loaded on Vulcan XC 72 carbon to get required wt% metal loading by conventional wet-impregnation method. That is 20 mg of Vulcan XC 72R carbon and required amount of 0.01 molar concentration ruthenium (111) chloride hydrate (RuCl3.3H20 have been stirred vigorously at room temperature for about 3 h. The resulting composite has been dried at 100 °C to make it free from solvent. The reducing agent i.e., reduced silicotungstic acid has been prepared using zinc powder. Preparation of reduced silicotungstic acid'. In a typical procedure 4 tnL of 0.01 M silicotungastic acid (H4S1W12O40.XH2O) in water has been treated with 50 fold excess zinc metal powder (mole ratio of SiW^C^o to Zn is l:50)n in a beaker. An excess Zn° has been used to ensure complete reduction of the polyoxometalate. Immediate color change of the solution to blue color indicated the formation of reduced silicotungstic acid [Si^W^C^]5" The solution was filtered to remove the remaining Zn° and filtrate has been used as reducing agent. 4 mL of reduced silicotungstic acid has been added to the ruthenium impregnated vulcan XC72. The composite has been placed at the center of unmodified domestic microwave oven operating at a frequency of 2450 MHz and a power of 700W and heated under microwave irradiation for 60 sec. Immediately blue color of the solution has changed to colorless indicating the oxidation process of polyoxometalate. This ensured that electron transfer has been taken place from polyoxometalate to ruthenium ions and apparently the reduction of ruthenium into its metallic oxidation state. The sample has been washed with 2 mL of water and twice with 2 mL of ethanol. The composite material has been extracted by ultracentrifugation. The obtained material has been dried under vacuum at room temperature for 12h. Example 2 To see the effect of polyoxometalate on the activity of the composite material, 20% Ru/C composite without polyoxometalate has been prepared by hydrogen reduction method. That is 20 mg of Vulcan XC 72R carbon and required amount of 0.01 molar concentration ruthenium (III) chloride hydrate (RUCI3.3H2O) (to prepare 20 wt% ruthenium loading) have been stirred vigorously at room temperature for about 3 h. The resulting composite has been dried at 100 °C to make it free bom solvent The impregnated material has been heated at 450° C under flowing H2 gas atmosphere in a tubular furnace for 3h. Example 3 Specific amounts of ruthenium (III) chloride hydrate (lOmM) has been loaded on Vulcan XC 72 carbon to get required wt% metal loading by conventional wet-impregnation method. That is 20 mg of Vulcan XC 72R carbon and required amount of 0.01 molar concentration ruthenium (III) chloride hydrate (RuCl3.3H20 have been stirred vigorously at room temperature for about 3 h. The resulting composite has been dried at 100 °C to make it free from solvent. Meanwhile the reducing agent i.e., reduced phosphomolybdic acid has been prepared. Preparation of reduced Phosphomolybdic acid: In a typical procedure 4 mL of 0.01 M phophomolybdic acid (H3PM012O40.XH2O) in water has been treated with 50 fold excess zinc metal powder (mole ratio of H3PM012O40 to Zn is 1:50) in a beaker. An excess Z,n° has been used to ensure complete reduction of the polyoxometalate. Immediate color change of the solution to blue color indicated the formation of reduced phophomolybdic acid [PM012O40]5". The solution was filtered to remove the remaining Zn° and filtrate has been used as reducing agent. 4 mL of reduced phosphomolybdic acid thus prepared by the above procedure has been added to the ruthenium impregnated Vulcan XC72. The composite has been placed at the center of unmodified domestic microwave oven operating at a frequency of 2450 MHz and a power of 700W and heated under microwave irradiation for 60 sec. Immediately blue color of the solution has changed to yellow color indicating the oxidation process of polyoxometalate. This ensured that electron transfer has been taken place from polyoxometalate to ruthenium ions and apparently the reduction of ruthenium into its metallic oxidation state. The sample has been washed with 2 mL of water and twice with 2 mL of ethanol. The composite material has been extracted by ultracentrifugation. The obtained material has been dried under vacuum at room temperature for I2h. Example 4 Specific amounts of ruthenium (III) chloride hydrate (lOmM) has been loaded on Vulcan XC 12 carbon to get required xvt% metal loading by conventional wet-impregnation method. That is 20 mg of Vulcan XC 72R carbon and required amount of 0.01 molar concentration ruthenium (III) chloride hydrate (RuCl3.3H20 have been stirred vigorously at room temperature for about 3 h. The resulting composite has been dried at 100 °C to make it free from solvent Mean while the reducing agent i.e., reduced phosphomolybdovanadic acid has been prepared. Preparation of reduced phosphomolybovanadic acid: In a typical procedure 4 mL of 0.01 M phophomolybdic acid (H5PM010V2O40.XH2O) in water has been treated with 50 fold excess zinc metal powder (mole ratio of H5PM010V2O40 to Zn is 1:50)n in a beaker. An excess Zn° has been used to ensure complete reduction of the polyoxometalate. Immediate color change of the solution to blue color indicated the formation of reduced phophomolybdovanadic acid. The solution was filtered to remove the remaining Zn° and filtrate has been used as reducing agent. 4 mL of reduced phosphomolybovanadic acid thus prepared by the above procedure has been added to the ruthenium impregnated Vulcan XC72. The composite has been placed at the center of unmodified domestic microwave oven operating at a frequency of 2450 MHz and a power of 700W and heated under microwave irradiation for 60 sec. Immediately blue color of the solution has changed to yellow color indicating the oxidation process of polyoxometalate. This ensured that electron transfer has been taken place from polyoxometalate to ruthenium ions and apparently the reduction of ruthenium into its metallic oxidation state. The sample has been washed with 2 mL of water and also twice with 2 mL of ethatvol. The composite material has been extracted by ultracentrifugation. The obtained material has been dried under vacuum at room temperature for 12h. We Claim: 1 A method of manufacture of an electrode based on Ru-polyoxometalate for a supercapacitor comprising the steps of impregnation of the ruthenium metal precursor, namely, aqueous solution of RuCl3.xHaO on the conductive carbon support, namely, Vulcan XC72R; preparation of reducing agent from polyoxometalate solution; reduction of the impregnated metal on carbon support obtained into its metallic oxidation state; separating the unadsorbed polyoxometalate; drying the sample at room temperature; dispersing the electrode material, water; placing the electrode material from the above dispersion obtained on glassy carbon electrode; drying the electrode material obtained; placing a nation solution as a binder on the electrode so obtained. 2. A method as claimed in Claim 1 wherein the preparation of reducing agent from polyoxometalate solution is carried out by addition of Zn metal powder. 3. A method as claimed in any one of the preceding Claims wherein the reduction of the impregnated metal on carbon support obtained into its metallic oxidation state is carried out by the addition of reduced polyoxometalate solution and simultaneous irradiation with microwave radiation by placing the vessel in a domestic microwave oven operating at a frequency of 2450 MHz (power 700W) for 1 minute. 4. A method as claimed in any one of the preceding Claims wherein the unadsorbed polyoxometalate is separated by washing with water and ethanol and centrifuging the material at a speed of 10,000 rps. 5. A method as claimed in any one of the preceding Claims wherein the sample is dried at room temperature under vacuum for 12 h. ©> A method as claimed in any one of the prece4ding Claims wherein 10 mg of the electrode material is dispersed in 200 \|xl water. *} & A method as claimed in any one of the preceding Claims wherein 10 \|il of electrode material from the dispersion is placed on glassy carbon electrode (Area = 0.07 cm2). 10 An electrode based on Ru-polyoxometalate for a supercapacitor \ whenever manufactured by a method as claimed in any one of the preceding Claims.

Full Text

1
)
Reports show that ruthenium oxide is one of the most promising materials^ for supercapaeitors owing to high specific capacitance and highly electrochemical reversibility. However, improvement of the utilization of Ru02.nH20 is the major issue for its practical use due to its high cost.
We have adopted polyoxometalates as reducing agent to prepare
nanoparticulate ruthenium on carbon supercapacitor material. The excellent
redox property and high dispersion of charge by polyoxometalates has
motivated us to employ them to produce ruthenium nanoparticles. During
this process, polyoxometalates duo to their high adsorption capability, get
adsorbed onto the material and thereby stabilize the ruthenium nanoparticles
on carbon support.
This invention proposes ruthenium nanoparticles stabilized by
polyoxometalate on carbon based electrode to increase the performance of
the electrochemical capacitor.
This invention further proposes manufacture of highly dispersed ruthenium
nanoparticles on carbon support to increase the effective utilization of active
material.
In this invention polyoxometalate performs the diverse roles of reducing
agent as well as stabilizing agent
In this invention the supercapacitor electrode has a high specific
capacitance with low loading of ruthenium weight percentage in the
electrode material in the form nanoparticles along with polyoxometalate
supported on carbon.
Preferably, the electrode comprises 10, 20 and 40% by weight of ruthenium nanoparticles on conductive carbon.

This invention increases the specific capacitance of the conductive carbon Used to considerably high values by modifying it with ruthenium nanoparticles stabilized polyoxometaiates.
The method of manufacture of an electrode based on Ru-polyoxometalate for a supercapacitor, according to this invention, comprises the steps of impregnation of the ruthenium metal precursor, namely, aqueous solution of RuCl3.xH20 on the conductive carbon support, namely, Vulcan XC72R; preparation of reducing agent from polyoxometalate solution; reduction of the impregnated metal on carbon support obtained into its metallic oxidation state; separating the unadsorbed polyoxometalate; drying the sample at room temperature; dispersing the electrode material in water; placing electrode material from the above dispersion obtained on glassy carbon electrode; drying the electrode material obtained; placing nafion solution as a binder on the electrode so obtained.
In the preceding paragraph, the following steps are preferably carried out:

The preparation of reducing agent from polyoxometalate solution is carried
out by addition of Zn metal powder.
The reduction of the impregnated metal on carbon support obtained into its
metallic oxidation state is carried out by the addition of reduced
polyoxometalate solution and simultaneous irradiation with microwave
radiation by placing the vessel in a domestic microwave oven operating at a
frequency of 2450 MHz (power 700W) for 1 minute.
The unadsorbed polyoxometalate is separated by washing with water and
ethanol and centrifuging the material at a speed of 10,000 rps.
The sample is dried at room temperature under vacuum for 12 h.
10 mg of the electrode material is dispersed in 200 ul water.
10 ul of electrode material from the dispersion is placed on glassy carbon
electrode (Area = 0.07 cm2).
The electrode material obtained is dried at 70° C in a hot air oven.
5 ul of nation solution (10% solution in methanol) is placed on the electrode
as a binder.
Example: 1 Carbon Black: (Vulcan XC-72R) with specific surface area (BET) of 250 m2g_1 was used as the carbon support.
Specific amounts of ruthenium (III) chloride hydrate (lOmM) was loaded on Vulcan XC 72 carbon to get required wt% metal loading by conventional wet-impregnation method. That is 20 mg of Vulcan XC 72R carbon and required amount of 0.01 molar concentration ruthenium (111) chloride hydrate (RuCl3.3H20 have been stirred vigorously at room temperature for

about 3 h. The resulting composite has been dried at 100 °C to make it free from solvent. The reducing agent i.e., reduced silicotungstic acid has been prepared using zinc powder.
Preparation of reduced silicotungstic acid'. In a typical procedure 4 tnL of 0.01 M silicotungastic acid (H4S1W12O40.XH2O) in water has been treated with 50 fold excess zinc metal powder (mole ratio of SiW^C^o to Zn is l:50)n in a beaker. An excess Zn° has been used to ensure complete reduction of the polyoxometalate. Immediate color change of the solution to blue color indicated the formation of reduced silicotungstic acid [Si^W^C^]5" The solution was filtered to remove the remaining Zn° and filtrate has been used as reducing agent.
4 mL of reduced silicotungstic acid has been added to the ruthenium impregnated vulcan XC72. The composite has been placed at the center of unmodified domestic microwave oven operating at a frequency of 2450 MHz and a power of 700W and heated under microwave irradiation for 60 sec. Immediately blue color of the solution has changed to colorless indicating the oxidation process of polyoxometalate. This ensured that electron transfer has been taken place from polyoxometalate to ruthenium ions and apparently the reduction of ruthenium into its metallic oxidation state.
The sample has been washed with 2 mL of water and twice with 2 mL of ethanol. The composite material has been extracted by ultracentrifugation. The obtained material has been dried under vacuum at room temperature for 12h.

Example 2 To see the effect of polyoxometalate on the activity of the composite material, 20% Ru/C composite without polyoxometalate has been prepared by hydrogen reduction method. That is 20 mg of Vulcan XC 72R carbon and required amount of 0.01 molar concentration ruthenium (III) chloride hydrate (RUCI3.3H2O) (to prepare 20 wt% ruthenium loading) have been stirred vigorously at room temperature for about 3 h. The resulting
composite has been dried at 100 °C to make it free bom solvent The
impregnated material has been heated at 450° C under flowing H2 gas
atmosphere in a tubular furnace for 3h.
Example 3 Specific amounts of ruthenium (III) chloride hydrate (lOmM) has been
loaded on Vulcan XC 72 carbon to get required wt% metal loading by
conventional wet-impregnation method. That is 20 mg of Vulcan XC 72R
carbon and required amount of 0.01 molar concentration ruthenium (III)
chloride hydrate (RuCl3.3H20 have been stirred vigorously at room
temperature for about 3 h. The resulting composite has been dried at 100 °C to make it free from solvent. Meanwhile the reducing agent i.e., reduced phosphomolybdic acid has been prepared.
Preparation of reduced Phosphomolybdic acid: In a typical procedure 4 mL of 0.01 M phophomolybdic acid (H3PM012O40.XH2O) in water has been treated with 50 fold excess zinc metal powder (mole ratio of H3PM012O40 to Zn is 1:50) in a beaker. An excess Z,n° has been used to ensure complete reduction of the polyoxometalate. Immediate color change of the solution to blue color indicated the formation of reduced phophomolybdic acid [PM012O40]5". The solution was filtered to remove the remaining Zn° and filtrate has been used as reducing agent. 4 mL of reduced phosphomolybdic

acid thus prepared by the above procedure has been added to the ruthenium impregnated Vulcan XC72. The composite has been placed at the center of unmodified domestic microwave oven operating at a frequency of 2450 MHz and a power of 700W and heated under microwave irradiation for 60 sec. Immediately blue color of the solution has changed to yellow color indicating the oxidation process of polyoxometalate. This ensured that electron transfer has been taken place from polyoxometalate to ruthenium ions and apparently the reduction of ruthenium into its metallic oxidation state.
The sample has been washed with 2 mL of water and twice with 2 mL of ethanol. The composite material has been extracted by ultracentrifugation. The obtained material has been dried under vacuum at room temperature for I2h.
Example 4 Specific amounts of ruthenium (III) chloride hydrate (lOmM) has been loaded on Vulcan XC 12 carbon to get required xvt% metal loading by conventional wet-impregnation method. That is 20 mg of Vulcan XC 72R carbon and required amount of 0.01 molar concentration ruthenium (III) chloride hydrate (RuCl3.3H20 have been stirred vigorously at room temperature for about 3 h. The resulting composite has been dried at 100 °C to make it free from solvent Mean while the reducing agent i.e., reduced phosphomolybdovanadic acid has been prepared.
Preparation of reduced phosphomolybovanadic acid: In a typical procedure 4 mL of 0.01 M phophomolybdic acid (H5PM010V2O40.XH2O) in water has been treated with 50 fold excess zinc metal powder (mole ratio of H5PM010V2O40 to Zn is 1:50)n in a beaker. An excess Zn° has been used to ensure complete reduction of the polyoxometalate. Immediate color change

of the solution to blue color indicated the formation of reduced phophomolybdovanadic acid. The solution was filtered to remove the remaining Zn° and filtrate has been used as reducing agent. 4 mL of reduced phosphomolybovanadic acid thus prepared by the above procedure has been added to the ruthenium impregnated Vulcan XC72. The composite has been placed at the center of unmodified domestic microwave oven operating at a frequency of 2450 MHz and a power of 700W and heated under microwave irradiation for 60 sec. Immediately blue color of the solution has changed to yellow color indicating the oxidation process of polyoxometalate. This ensured that electron transfer has been taken place from polyoxometalate to ruthenium ions and apparently the reduction of ruthenium into its metallic oxidation state.
The sample has been washed with 2 mL of water and also twice with 2 mL of ethatvol. The composite material has been extracted by ultracentrifugation. The obtained material has been dried under vacuum at room temperature for 12h.

We Claim:
1 A method of manufacture of an electrode based on Ru-polyoxometalate for a supercapacitor comprising the steps of impregnation of the ruthenium metal precursor, namely, aqueous solution of RuCl3.xHaO on the conductive carbon support, namely, Vulcan XC72R; preparation of reducing agent from polyoxometalate solution; reduction of the impregnated metal on carbon support obtained into its metallic oxidation state; separating the unadsorbed polyoxometalate; drying the sample at room temperature; dispersing the electrode material, water; placing the electrode material from the above dispersion obtained on glassy carbon electrode; drying the electrode material obtained; placing a nation solution as a binder on the electrode so obtained.
2. A method as claimed in Claim 1 wherein the preparation of reducing agent from polyoxometalate solution is carried out by addition of Zn metal powder.
3. A method as claimed in any one of the preceding Claims wherein the reduction of the impregnated metal on carbon support obtained into its metallic oxidation state is carried out by the addition of reduced polyoxometalate solution and simultaneous irradiation with microwave radiation by placing the vessel in a domestic microwave oven operating at a frequency of 2450 MHz (power 700W) for 1 minute.

4. A method as claimed in any one of the preceding Claims wherein the
unadsorbed polyoxometalate is separated by washing with water and
ethanol and centrifuging the material at a speed of 10,000 rps.
5. A method as claimed in any one of the preceding Claims wherein the
sample is dried at room temperature under vacuum for 12 h.
©> A method as claimed in any one of the prece4ding Claims wherein 10 mg of the electrode material is dispersed in 200 |xl water.
*} & A method as claimed in any one of the preceding Claims wherein 10 |il of electrode material from the dispersion is placed on glassy carbon electrode (Area = 0.07 cm2).

10 An electrode based on Ru-polyoxometalate for a supercapacitor \ whenever manufactured by a method as claimed in any one of the preceding Claims.

Documents:

1578-CHE-2007 AMENDED CLAIMS 07-06-2011.pdf

1578-CHE-2007 EXAMINATION REPORT REPLY RECEIVED 07-06-2011.pdf

1578-che-2007-abstract.pdf

1578-che-2007-claims.pdf

1578-che-2007-correspondnece-others.pdf

1578-che-2007-description(complete).pdf

1578-che-2007-form 1.pdf

1578-che-2007-form 18.pdf

1578-che-2007-form 26.pdf

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Patent Number

248139

Indian Patent Application Number

1578/CHE/2007

PG Journal Number

25/2011

Publication Date

24-Jun-2011

Grant Date

21-Jun-2011

Date of Filing

20-Jul-2007

Name of Patentee

INDIAN INSTITUTE OF TECHNOLOGY

Applicant Address

IIT P.O CHENNAI 600 036

Inventors:

#	Inventor's Name	Inventor's Address
1	PILLI SATYANANDA KISHORE	RESEARCH SCHOLAR DEPARTMENT OF CHEMISTRY IIT, CHENNAI 36
2	DR. BALASUBRAMANIAN VISWANATHAN	PROFESSOR DEPARTMENT OF CHEMISTRY IIT, CHENNAI 600 036
3	DR. THIRUKKALLAM KANTHADAI VARADARAJAN	PROFESSOR DEPARTMENT OF CHEMISTRY IIT, CHENNAI 600036

PCT International Classification Number

H01G 9/058

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA