Electrolytic Synthesis of Hydrogen Peroxide Directly from Water and Application Thereof

Abstract

Provided is an electrochemical cell for generating hydrogen peroxide (H202) directly from water, and an application thereof. The electrochemical cell includes: water-soluble electrolyte; an electrode structure A, in which hydrogen peroxide is generated by oxidizing water containing city water (CW) or electrolytes when voltage of time dependant polarity is applied; and an electrode structure B, in which hydrogen peroxide is generated by reducing water of the water-soluble electrolyte when the voltage of time dependant polarity is applied, wherein the polarity reversal of the voltage Ve is performed periodically or non-periodically according to the time between positive (+) voltage and negative (−) voltage.

Description

TECHNICAL FIELD

The present invention relates to an electrochemical cell for electrolytic generation of hydrogen peroxide (H₂O₂) directly from aqueous solution with no requirement for inflow of oxygen (O₂) or air, a method for generating hydrogen peroxide, and an application thereof, and the electrolysis is performed by voltage whose polarity varies from certain positive voltages to negative ones.

BACKGROUND ART

Hydrogen peroxide (H₂O₂) is a strong yet environmentally benign oxidant. Hydrogen peroxide is applied to chemical synthesis, water treatment, pulp and paper industry and waste water treatment. Hydrogen peroxide is used as a safe and benign alternative for chlorine because of its environment compatibility. Also, hydrogen peroxide is used in fields aiming at generating and supplying oxygen acquired in decomposition of hydrogen peroxide. More recently, there are emerging interests in its applications in diverse scenarios such as sterilization/pasteurization/sanitary functions and/or an oxygen supplying function of a swimming place, Heating, Ventilating and Air-Conditioning (HVAC), a dish washer, a washing machine, a refrigerator, a humidifier, and an air cleaner.

Synthetic processes of the hydrogen peroxide reported until now are as follows.

M. Giomoa et al. disclosed electro-generation of hydrogen peroxide using an oxygen-reducing gas-diffusion electrode (Electrochimica Acta, 54 (2008) 808-815). L. Wang et al. disclosed degradation of bisphenol A (BPA) and simultaneous formation of hydrogen peroxide induced by glow discharge plasma (Journal of Hazardous Materials 154 (2008) 1106-1114).

M. Panizza et al. disclosed electro-generation of hydrogen peroxide in solution with low ionic strength using a gas diffusion cathode fed with air (Electrochimica Acta 54 (2008) 876-878). J. C. Forti et al. reported improved H₂O₂ generation efficiency using oxygen-fed graphite/PTFE electrodes modified by 2-ethylanthraquinone (Journal of Electroanalytical Chemistry 601 (2007) 63-67). Also, I. Yamanaka synthesized neutral H₂O₂ by Electrolysis of Water and O₂.

R. Gopal claimed improvement in the synthesis of acidic, aqueous solutions of hydrogen peroxide employing organic redox catalysts in a gas diffusion electrode provided with oxygen (U.S. Pat. No. 6,712,949). Lehmann et al. claimed a synthesis process for hydrogen peroxide by the electrochemical reaction of oxygen and hydrogen in a fuel cell (U.S. Pat. No. 6,685,818).

Y. Nakajima et al. disclosed a method of generating H₂O₂ using oxygen-containing gas and an electrolyte in a cathode chamber housing a gas diffusion cathode (U.S. Pat. No. 6,773,575). M. Uno et al. declared stable production of hydrogen peroxide over a long period of time in an electrolyte free from multivalent metal ions (U.S. Pat. No. 6,767,447).

In spite of the diverse processes, the most industrially efficient prior route for large scale synthesis of hydrogen peroxide is the anthraquinone-based approach. It however is very inconvenient for small scale onsite or distributed generation for instant consumption.

Generally, electrochemical or electrolytic methods for hydrogen peroxide synthesis offer some important advantages over the anthraquinone method, including higher purity, fewer separation steps, fewer unwanted by-products, greater safety and fewer environmental concerns.

The most traditional electrolytic synthesis, i.e., the persulfate route, needs very corrosive electrolyte and a platinum anode. Still its efficiency is very low at some 25%.

The more recent approach starts with oxygen and electrochemically reduces oxygen in a gas diffusion layer or a trickle bed reactor. It nevertheless has the following deficiency: 1) working typically on alkaline electrolyte; 2) the requirement for pure oxygen; 3) the concentration achievable is low at a few percent.

DISCLOSURE OF INVENTION

Technical Problem

An embodiment of the present invention is directed to provide an electrolysis cell which is driven by a voltage of time dependent polarity and an objective of the present invention is to provide a novel electrochemical cell which generates hydrogen peroxide (H₂O₂) directly from water.

Another embodiment of the present invention is directed to provide a method for producing oxygenated water using the electrochemical cell and an apparatus comprising the electrochemical cell.

Solution to Problem

To achieve the objective of the present invention, the present invention provides an electrochemical cell for generating hydrogen peroxide (H₂O₂), comprising:

• • water-soluble electrolyte;
  • an electrode structure A, which contacts with the water-soluble electrolyte and in which hydrogen peroxide is generated by oxidizing water containing city water (CW) or electrolytes when voltage of time dependant polarity is applied; and
  • an electrode structure B, which contacts with the water-soluble electrolyte but is spatially separated from the electrode structure A, and in which hydrogen (H₂) is generated by reducing water of the water-soluble electrolyte solution when the voltage of time dependant polarity is applied,
  • wherein the voltage of time dependant polarity is a voltage V_e (V_e=V_A−V_B), which is the potential difference of electrode structures A and B; and as shown in FIG. 4, the polarity reversal of the voltage V_e is performed periodically or non-periodically according to the time in sequence of positive (+) voltage, negative (−) voltage, positive (+) voltage, and negative (−) voltage, or as shown in FIG. 5, a wave form of a case that the negative voltage is close to 0 when the positive and negative voltages are alternating is included.

The electrochemical cell may be an electrolysis device for generating hydrogen peroxide when the voltage of time dependant polarity is applied between the two electrode structures with or without external oxygen or air inflow inside the electrochemical cell. Therefore, the external oxygen or air may or may not enter the electrochemical cell of the present invention.

In the present invention, the negative voltage may be in an absolute value smaller than the positive voltage and a time average of the voltage V_e is positive. The voltage of the time dependant polarity has a polarity switching frequency between 10⁻⁶ to 10⁺⁸ Hz and amplitude of −200 volt to +300 volt, preferably −50 volt to +100 volt, stably −20 volt to +50 volt, more stably −2 volt to +5 volt.

The electrode structure A may include porous conducting material which is electrochemically stable in the water-soluble electrolyte and hydrogen peroxide. The electrode structure B may include porous conducting material which is electrochemically stable in the water-soluble electrolyte. The electrode structure is prepared to be in a state that catalyst components are supported in or contact with an electrode support structure (substrate). The electrode structure is not limited but ceramic, graphite and conductive metals may be used.

The electrochemical cell of the present invention may further include a separator membrane or an ion-exchange membrane which is located between the electrode structures A and B and blocks electrons while conducting ions.

The electrode structure A may include at least one catalyst selected from a group consisting of O, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Sr, Ba and carbon in their elemental or compound forms. The electrode structure B may include at least one catalyst selected from a group consisting of H, Ti, Zr, Hf, V, Nb, Ta and carbon in their elemental or compound forms. The water-soluble electrolyte is not limited but may include alkali metals, alkali earth metals and rare earth metals.

In the present invention, the voltage of the time dependant polarity may be applied using a power source outside the electrochemical cell.

Further, the present invention provides an apparatus comprising an electrochemical cell for generating hydrogen peroxide. The apparatus may be a pasteurization device, a sanitary device, a sterilization device or an oxygen supply device through decompositon of hydrogen peroxide but is not limited thereto.

Further, the present invention provides a method for generating hydrogen peroxide from an aqueous solution by applying voltage of time dependant polarity between electrode structures A and B inside an electrochemical cell for generating hydrogen peroxide.

In the present invention, hydrogen peroxide may be generated with or without external oxygen or air inflow inside the electrochemical cell.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, hydrogen peroxide (H₂O₂) is generated directly from water. This method offers a number of advantages, such as convenience and low maintenance, as well as getting rid of an oxygen/air tank or an external oxygen/air source. This method can work on tap water or dilute sodium carbonate or sodium bicarbonate as the electrolyte and provide a convenient method of H2O2 generation for every day household and office use, such as sterilization/sanitary/pasteurization, air-purification, deodorization and oxygen supply through decomposition of hydrogen peroxide.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the present invention will become apparent from the following description of preferred embodiments given in conjunction with the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of an electrochemical cell generating hydrogen peroxide in accordance with an embodiment of the present invention.

FIGS. 2 and 3 are circuit diagrams showing a power source generating voltage V_e in the electrochemical cell in accordance with an embodiment of the present invention.

FIGS. 4 and 5 are graphs showing variation of the voltage V, in accordance with an embodiment of the present invention.

FIG. 6 shows multiple cells including n cells connected in series and m cells connected in parallel in accordance with an embodiment of the present invention.

FIG. 7 is a graph showing concentration change of hydrogen peroxide according to an actual operation in accordance with an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

As one embodiment of the present invention, a novel electrochemical cell is constructed to generate hydrogen peroxide (H₂O₂) directly from water. It comprises two electrode structures and a water-soluble electrolyte. A voltage of time dependent polarity is applied across the electrode structures to generate H₂O₂.

The electrochemical cell of the present invention offers a number of advantages from the point of view of H₂O₂ users, such as convenience and low maintenance, as well as getting rid of an oxygen gas tank or an external oxygen source. Also, the electrochemical cell of the present invention can work on tap water or aqueous sodium carbonate solution or sodium bicarbonate as the electrolyte and provide a convenient method of H₂O₂ generation for every day household and office use, such as sterilization/sanitary/pasteurization, air-purification, deodorization and oxygen supply through decomposition of hydrogen peroxide.

As another embodiment, a method of generating H₂O₂ without substantial oxygen/air inflow or without any oxygen/air inflow is described. Unlike most prior arts, the present invention makes hydrogen peroxide from oxidation of water, instead of reduction of gaseous oxygen. This greatly reduces the burden of logistics associated with transporting and installation of oxygen gas tanks or oxygen generation units that generate oxygen through separation from the air.

In the present invention, substantial external oxygen or air inflow is defined as equal to or more than 10% of the stoichiometric amount of external oxygen needed to reach a fixed H₂O₂ generation rate, in the traditional cathodic hydrogen peroxide process, which electrochemically reduces solvated or bubbled oxygen. The present invention is directed towards H₂O₂ generation preferably without external oxygen or air inflow.

In the present invention, a voltage of time dependant polarity, i.e., a voltage whose polarity varies depending on the time, is applied across the electrode structures A and B as the voltage whose polarity is repeatedly reversed with time, i.e., the voltage reversed in sequence of positive (+) voltage, negative (−) voltage, positive (+) voltage, and negative (−) voltage. The polarity reversal can be done periodically or non-periodically. When the voltage of time dependant polarity is periodically switched, a common wave form can be employed such as sine, cosine, square or triangle.

The polarity switching is an essential element of the present invention and surprisingly leads to H₂O₂, instead of O₂, as the electro-oxidation product. The applied voltage of time dependant polarity may have a switching period of time dependant polarity ranging from 10⁻⁶ Hz to 10⁸ Hz. The voltage may also have a time dependant amplitude which preferably lies in the range of −200 and +300 volt, more preferably between 0 volt and +115 volt. Again, the voltage of time dependant polarity refers to the potential difference of electrode structure A minus B.

In the present invention, an electrode structure is defined as an assembly of a current collector preferably in electrical contact with an electrochemically active electrode. The electrochemically active electrode may be made from conducting porous materials. A copper wire, a stainless steel plate, or a titanium sheet is a typical current collector. A carbon cloth with a titanium sheet current collector (lead-out) is a typical electrode structure. A ceramic sheet or Honeycomb structures of a microporous structure of impregnating or having catalyst is a typical electrode structure.

A porous material is defined in the present invention as a material with void volume of equal to or more than 5%, or a material with a high specific surface area that is higher than 10 cm²/gram. A Raney nickel, a carbon cloth and a ceramic Honeycomb block are typical porous materials. The porous material, when employed, is always in electrical contact with the current collector to provide high surface area for electrode reactions. Porous or spongy metals such as nickel foams, Raney nickel, a titanium sponge, the porous or high specific surface area carbon, or microporous materials made of the ceramic material holding electrolytes solutions function as both a current collector and an electrochemically active electrode.

To be specific, an electrode structure A described herein provides a location on which H₂O₂ is generated through oxidation of water. Also, an electrode structure B described herein provides a location on which H₂ is generated through the reduction of water. Typically, each of the electrode structures A and B may be made of a conducting current collector in electrical contact with a porous conducting material. The high surface area of the porous conducting materials greatly enhanced the current efficiency and the H₂O₂ generation rate.

In the present invention, the porous conducting materials used in the electrode structures A and B preferably have a conductivity of greater than 10⁻³ S/cm. The pore volume of the material is preferably higher than 5%, even more preferably higher than 25%. As an alternative to the porous conducting materials, a conducting plate with a high surface area can also be used.

Both electrode structures A and B may be structurally rigid and have a form of a compartment in which the work aqueous solution can flow. The material requirement of the electrode structures A and B is such that they are conducting and electrochemically stable in the water-soluble electrolyte and/or in the H₂O₂ solution. Other functions of the said electrode structures are to offer structural rigidity and form the compartment in which the work aqueous solution can flow and the generated H² can bubble out. Another function of the electrode structures A and B is to provide a path of low electrical resistance to the external electrolysis power source.

In the present invention, the electrochemical cell may further include a separator membrane or an ion-exchange membrane that is located between the electrode structures A and B and blocks electrons while conducting ions. The separator membrane or the ion-exchange membrane is used to improve the efficiency of the H₂O₂ generation. It serves as a physical barrier to prevent generated H₂O₂ at the electrode structure A from diffusing to the electrode structure B and its reduction by electrode structure B to water again. The separator membrane or the ion-exchange membrane is not specifically limited under a requirement that they are chemically stable in the electrolyte and in the presence of H₂O₂. The separator membrane or the ion-exchange membrane may be unlimitedly selected from Nafion, i.e., cation exchange resin membrane, mesoporous and microporous membranes, and nano-filtration membranes.

The electrochemical cell of the present invention may include a third electrode structure to provide other functions such as monitoring the product generation rate or optimizing the product parameters.

The generation of H₂O₂ at the electrode structure A and H₂ at the electrode structure B is preferably catalyzed with catalysts. In the electrode structure A for generating H₂O₂, the preferred catalyst is selected from a group consisting of O, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Sr, Ba and carbon in their elemental or compound forms. In the electrode structure B for generating H₂, the preferred catalyst is selected from a group consisting of H, Ti, Zr, Hf, V, Nb, Ta, and carbon in their elemental or compound forms. The catalyst is preferably loaded in the conducting porous materials. It may also be in the dissolved form in the electrolyte.

The generated H₂O₂ may be separated and stored or applied by an electrolyte recirculation unit. When O₂ is the desirable end product, the generated H₂O₂ may be decomposed on a decomposition catalyst to O₂.

The electrochemical cell of the present invention may be used in a variety of applications where sterilization/sanitary/pasteurization and/or oxygen supply functions are needed such as swimming pool, dishwasher, washing machine, humidifier, refrigerator, air cleaner and HVAC system.

The electrochemical cell of the present invention can be used in a variety of energy storage applications where electrical energy is converted into chemical energy of hydrogen peroxide and hydrogen generated inside the electrochemical cell. The hydrogen peroxide and hydrogen thus generated are utilized to react in the electrochemical cell or other separate electrochemical cells to generate electricity.

Hereinafter, the embodiments of the present invention will be described in detail with reference to accompanying drawings. The present invention is not limited to the drawings introduced below and may be specified into other formats.

FIG. 1 is a cross-sectional view of the electrochemical cell generating hydrogen peroxide in accordance with an embodiment of the present invention. The electrochemical cell of FIG. 1 includes an electrode structure A 10, an electrode structure B 20, an optionally used separator membrane 30, and a water-soluble electrolyte 40, which is water containing city water (CW) or electrolytes, and has a structure that the voltage of time dependant polarity is applied between the electrode structures A 10 and B 20 through the power source.

An electrolysis voltage V_e satisfying V_e=V_A−V_B is not fixed to a single voltage during the electrolysis process. However, it varies from certain positive voltages to negative ones, and then switches back to positive ones again. Such alternation of the voltage polarity is repeated throughout the electrolysis process. For generation of H₂O₂ on the electrode structure A, the negative voltage should be in absolute value smaller than the positive voltage, so that the time average of voltage V, is positive. The time average of V_e is preferably to be between the thermodynamic redox potential of the reaction 2H₂O=H₂O₂+H₂, which is 1.77 volt in standard conditions, and that of the reaction 2H₂O=2 H₂+O₂, which is 1.22 volt.

FIGS. 2 and 3 are circuit diagrams showing a power source generating voltage V_e in the electrochemical cell in accordance with an embodiment of the present invention. FIGS. 2 and 3 are examples of the power source shown in FIG. 1 for facilitate the electrochemical cell of FIG. 1 to generate hydrogen peroxide. In FIGS. 2 and 3, V_e alternates between positive and negative values. A switch S in FIGS. 2 and 3 may be of either a mechanical or an electronic type. V₁ and V₂ are direct current (DC) voltage having opposite polarities for the switch S. The polarity of V, depends on time. FIG. 2 shows that at a certain time, the switch S is connected to V₁. Not long after that, the switch is disconnected from V₁ and connected to V₂, as shown in FIG. 3.

FIG. 4 is a graph showing variation of the voltage V, in accordance with an embodiment of the present invention. The particular example shown in FIG. 4 describes the time dependence of the electrolysis voltage V_e. It is also the voltage of the electrode structure A measured with respect to the electrode structure B, or V_e=V_A−V_B. In this example, the voltage alternates between a positive value of 2.2 volt and a negative one of −0.6 volt. Both the positive and the negative parts last for 5 seconds, then the switch to the opposite polarity occurs. The waveform of the voltage repeats itself every 10 seconds. In other words, the periodic voltage has a frequency of 0.1 Hz.

The voltage waveform of FIG. 4 is non-symmetric with respect to the zero voltage reference point. This non-symmetry is essential in generation of H2O2 in the electrochemical cell of FIG. 1. The key to successful electrolytic generation or the electrosynthesis of a certain compound molecule therefore includes: 1) alternating of polarity in the electrolysis voltage; and 2) the non-symmetry of the voltage waveform or the bias from zero voltage. In general, the time averaged voltage of alternating polarity is preferably to be biased towards the positive if the molecule to be synthesized is an oxidant. Conversely, such variable-polarity time averaged voltage is preferably to be biased negatively if the molecule is a reducing agent.

A specific example shown in FIG. 5 describes that the electrolysis voltage V, is rectified alternating current (AC) voltage of a time dependent polarity. In addition, the electrolysis voltage V_e is the same as the voltage of the electrode structure A measured correspondingly to the electrode structure B or satisfies that V_e=V_A−V_B. The voltage V_B applied to the electrode structure B is a negative voltage approximating 0. In this example, the voltage varies between +115 volt and a negative voltage approximating 0 volt. The positive voltage varies between a negative voltage approximating 0 volt and +115 volt for 0.01 second and continuously repeats the variation. That is, periodical voltage has a frequency of 100 Hz.

FIG. 6 shows multiple cells including n cells connected in series and m cells connected in parallel. In case of the serial connection, voltage of a value acquired by dividing the voltage input in the entire cells by the n number is applied to each of the n cells. In case of the parallel connection, voltage of a value acquired by dividing the current input in the entire cells by the m number is applied to each of the m cells. A size of the voltage and the current of the entire input power is determined by combination of the serial and parallel connections. According to a method for realizing the multiple cells, it is required to apply extremely high current to extremely low voltage or apply extremely low current to extremely high voltage in order to apply required input power when realized as a single cell. However, when it is technically difficult to realize the power supply source, it may be availably applied by being realized such that low voltage is applied to each cell although high voltage is applied to the entire cells through the cells connected in series or low current is applied to each cell although high current is applied to the entire cells through the cells connected in parallel.

FIG. 7 is a graph showing concentration change of hydrogen peroxide according to an actual operation. FIG. 7 shows concentration change of hydrogen peroxide according to alternation at intervals of 2.5 second in applied voltages of +2.2 volt and −1.7 volt. To be specific, each of the electrode structures A and B where the catalysts are supported has an area of 25 cm and a positive ion exchange resin having the same area is used between the electrodes. When the applied power is 220 mW and the amount of city water (CW) is 200 ml, an average concentration of hydrogen peroxide generated in the entire water for 5 hours is 1.3 wt % and the maximum concentration of hydrogen peroxide in the pore of the electrode structure A is 4 wt % to 10 wt %.

The principle of using a biased (non-symmetric) voltage of alternating polarity to electrolytically generate compounds can be utilized to the electrosynthesis of other chemicals, such as NaBH₄, NH₃BH₃, hydrazines, amines, oxyacids, and the salts of oxyacids, in either aqueous or non-aqueous solutions, or molten salts.

The present application contains subject matter related to U.S. Patent Application No. 61/178,967, registered in the US Patents and Trademark Office on May 16, 2009, the entire contents of which are incorporated herein by reference.

Those skilled in the art will appreciate that the conceptions and specific embodiments disclosed in the foregoing description may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present invention. Those skilled in the art will also appreciate that such equivalent embodiments do not depart from the spirit and scope of the invention as set forth in the appended claims.

Claims

1. An electrochemical cell for generating hydrogen peroxide (H2O2), comprising:

water-soluble electrolyte;

an electrode structure A, which contacts with the water-soluble electrolyte and in which hydrogen peroxide is generated by oxidizing water containing city water (CW) or electrolytes when voltage of time dependant polarity is applied; and

an electrode structure B, which contacts with the water-soluble electrolyte but is spatially separated from the electrode structure A, and in which hydrogen is generated by reducing water of the water-soluble electrolyte when the voltage of time dependant polarity is applied,

wherein the voltage of time dependant polarity is a voltage Ve (Ve=VA−VB), which is a potential difference of electrode structures A and B, the polarity reversal of the voltage Ve is performed periodically or non-periodically according to the time in sequence of positive (+) voltage, negative (−) voltage, positive (+) voltage, and negative (−) voltage.

2. The electrochemical cell of claim 1, wherein the negative voltage is in an absolute value smaller than the positive voltage and a time average of the voltage Ve is positive.

3. The electrochemical cell of claim 1, wherein the electrode structure A includes porous conducting material which is electrochemically stable in the water-soluble electrolyte and hydrogen peroxide.

4. The electrochemical cell of claim 1, wherein the electrode structure B includes porous conducting material which is electrochemically stable in the water-soluble electrolyte.

5. The electrochemical cell of claim 1, further comprising:

a separator membrane or an ion-exchange membrane which is located between the electrode structures A and B and blocks electrons while conducting ions.

6. The electrochemical cell of claim 1, wherein the electrode structure A includes at least one catalyst selected from a group consisting of O, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ca, Sr, Ba and carbon in their elemental or compound forms.

7. The electrochemical cell of claim 1, wherein the electrode structure B includes at least one catalyst selected from a group consisting of H, Ti, Zr, Hf, V, Nb, Ta and carbon in their elemental or compound forms.

8. The electrochemical cell of claim 1, wherein the water-soluble electrolyte includes at least one catalyst selected from a group consisting of alkali metal, alkali earth metal and rare earths.

9. The electrochemical cell of claim 1, wherein the voltage of the time dependant polarity has a polarity switching frequency between 10−6 to 10+8 Hz and amplitude of −200 volt to +300 volt.

10. The electrochemical cell of claim 1, wherein the voltage of the time dependant polarity is applied using a power source outside the electrochemical cell.

11. An apparatus including an electrochemical cell for generating hydrogen peroxide (H2O2) according to claim 1.

12. The apparatus of claim 11, wherein the apparatus is a pasteurization device, a sanitary device, a sterilization device or an oxygen supply device through decomposition of hydrogen peroxide.

13. A method for generating hydrogen peroxide (H2O2) from an aqueous solution by applying voltage of time dependant polarity between electrode structures A and B inside an electrochemical cell for generating hydrogen peroxide according to claim 1.

14. The method of claim 13, wherein hydrogen peroxide is generated with or without external oxygen or air inflow inside the electrochemical cell.