PROCESS FOR PREPARATION OF 2-D NANOSTRUCTURED SHEET BASED PHOTOCATALYST AND APPLICATION THEREOF

Abstract

The present invention relates to a process of microwave assisted preparation of atomically dispersed Ni modified (2-D) nanostructured sheets based photocatalyst mpg-C.sub.3N.sub.xNi. More particularly, the present invention relates to the drastically enhanced solar hydrogen at the rate from 200000 molg.sup.1h.sup.1 to 1000000 molg.sup.1h.sup.1 under sunlight by the atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi, depending upon its synthesis route without any significant loss in activity. The atomically dispersed Ni modified (2-D) nanostructured sheets based mpg-C.sub.3N.sub.xNi photocatalyst exhibit good stability, and is cost effective, providing excellent hydrogen generation production rate.

Claims

1. A process for microwave assisted preparation of atomically dispersed Ni modified (2-D) nanostructured sheets based photocatalyst (mpg-C.sub.3N.sub.xNi) wherein x is in a range of 3 to 4, exhibiting solar hydrogen at the rate ranging from 200000 molg.sup.1h.sup.1 to 1000000 molg.sup.1h.sup.1 under sunlight, comprising the steps of: i. adding carbon and nitrogen source (precursor) species in a Ludox solution to obtain a reaction precursor with the concentration ratio of 2:3 to 2:6; ii. adding etchant ammonium hydrogen difluoride with the concentration ranging from 2-5 M to the reaction precursor for removing the Ludox template followed by washing to obtain a mesoporous mpg-C.sub.3Nx; iii. adding Nickel source (precursor) species at different concentrations (in the range of 0.15 mM to 0.60 mM) in ethylene glycol and subsequently to the product obtained at step (ii) wherein Ni concentration is in a range of 2 to 10% with respect to mesoporous mpg-C.sub.3N.sub.x to obtain a first mixture; iv. adding sodium hydroxide with a hydrazine source in a volume ratio in a range of 1:30 to 1:300 into the first mixture and allowing to reflux at 65 C. for 5 hours to obtain a reaction mixture; and v. microwave heat treatment of the solution as obtained in step (iv) for a period in a range of 10 minutes to 30 minutes at a temperature in a range of 120-150 C. to obtain the atomically dispersed Ni modified mpg-C.sub.3N.sub.xNi.

2. The process for preparation of mpg-C.sub.3N.sub.xNi as claimed in claim 1, wherein the carbon and nitrogen source is selected from the group consisting of urea, melamine and cyanamide.

3. The process for preparation of mpg-C.sub.3N.sub.xNi as claimed in claim 1, wherein the Ni source is selected from the group consisting of nickel nitrate, and nickel tetrachloride.

4. The process for preparation of mpg-C.sub.3N.sub.xNi as claimed in claim 1, wherein said photocatalysts exhibit enhanced hydrogen generation, and is tunable by changing electron donors selected from the group consisting of triethylamine (TEA), and triethanolamine (TEOA).

5. The process for preparation of mpg-C.sub.3N.sub.xNi as claimed in claim 1, wherein said catalyst is useful to develop a renewable hydrogen generation device using solar radiation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention has other advantages and features which will be more readily apparent from the following detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawings, in which:

[0023] FIG. 1 represents the x-ray diffraction (XRD) pattern of 0.15 mM, 0.30 mM, 0.60 mM Nickel modified mpg-C.sub.3N.sub.x, in accordance with an embodiment of the present disclosure.

[0024] FIG. 2 represents (a) transmission electron microscope (TEM) image and (b) Energy Dispersive X-Ray Analysis (EDX) pattern of mpg-C.sub.3N.sub.x, in accordance with an embodiment of the present disclosure.

[0025] FIG. 3 represents x-ray photoelectron spectroscopy (XPS) analysis (a) C and (b) N for the atomically dispersed Ni modified catalysts mpg-C.sub.3Nx-Ni, in accordance with an embodiment of the present disclosure.

[0026] FIG. 4 represents the photoluminescence spectra for bare and Ni decorated mpg-C.sub.3N.sub.x, in accordance with an embodiment of the present disclosure.

[0027] FIG. 5 represents the Tauc plot of bare and Ni-decorated C.sub.3N.sub.x, showing energy gap values, in accordance with an embodiment of the present disclosure.

[0028] FIG. 6 represents the solar hydrogen generation of the atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi under sunlight, in accordance with an embodiment of the present disclosure.

[0029] FIG. 7 represents solar hydrogen generation using the solar simulator as the light source for the 0.15 mM Solvo-Ni-mpg-C.sub.3Nx (synthesized by solvothermal modification with Ni) and 0.15 mM Micro-Ni-mpg-C.sub.3Nx (microwave assisted modification with Ni) in water with triethanolamine (TEOA) electron donor, in accordance with an embodiment of the present disclosure.

[0030] FIG. 8 represents the photocatalytic CO.sub.2 reduction to CH.sub.4 using the solar simulator as the light source for the 0.30 mM Solvo-Ni-mpg-C.sub.3N.sub.x (synthesized by solvothermal modification with Ni), in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0031] The foregoing detailed description of the disclosure is elaborated to provide a clear understanding to the person who is skilled in the art. Additional features, embodiments and advantages of the invention will be described hereinafter which form the subject of the claims of the disclosure, However, the set forth disclosure provide in the specification will best be understood in conjunction with the appended claims and figures as provide heretofore. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent processes do not depart from the spirit and scope of the disclosure as set forth in the appended claims. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.

[0032] While the invention has been disclosed with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from its scope.

[0033] Throughout the specification and claims, the following terms take the meanings explicitly associated herein unless the context clearly dictates otherwise. The meaning of a, an, and the include plural references. The meaning of in includes in and on. Referring to the drawings, like numbers indicate like parts throughout the views.

[0034] The term at least one is used to mean one or more and thus includes individual components as well as mixtures/combinations.

[0035] Throughout this specification, unless the context requires otherwise the word comprise, and variations such as comprises and comprising, will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or step or group of element or steps.

[0036] The term including is used to mean including but not limited to. including and including but not limited to are used interchangeably.

[0037] All percentages, parts and ratios are based upon the total weight of the compositions of the present disclosure unless otherwise indicated. Ratios, concentrations, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a temperature range of 40 to 60 C. should be interpreted to include not only the explicitly recited limits of 40 to 60 C., but also to include sub-ranges, such as 40 to 50 C., 55 to 59 C. and so forth, as well as individual amounts, including fractional amounts, within the specified ranges, such as 44.5 C., 56.6 C. for example.

[0038] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference.

[0039] Additionally, a reference to the singular includes a reference to the plural unless otherwise stated or inconsistent with the disclosure herein. In line with the above objectives, the present invention provides a facile process for synthesizing atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi by a single pot modification by microwave treatment of mpg-C.sub.3N.sub.x mixed with Ni precursor at 150 C. from 10 minutes to 30 minutes. The nitrogen deficient mesoporous carbon nitride (mpg-C.sub.3N.sub.x) synthesized using the rational choice of uncommon precursor (cynamide), and introduced porosity using Ludox as template, and nitrogen deficiency by heating under controlled atmosphere.

[0040] The present invention developed a nitrogen deficient mesoporous carbon nitride (mpg-C.sub.3N.sub.x) photocatalyst, which has been synthesized using the rational choice of uncommon precursor, and introduced porosity using Ludox as template, and nitrogen deficiency by heating under controlled atmosphere to drive solar to chemical fuel (H.sub.2 and CH.sub.4) generation. Further modification of mpg-C.sub.3N.sub.x with Ni has been undertaken by microwave route to form atomically dispersed Ni decorated catalysts (mpg-C.sub.3N.sub.xNi) which exhibit drastic enhancement in the solar H.sub.2 generation activity. The light harvesting upon this modification has also been enhanced as the energy gap has reduced to 2.43 eV, from the typical value for g-C.sub.3N.sub.4 of 2.75 eV.

[0041] The present invention provides a process for the microwave assisted preparation of atomically dispersed Ni modified (2-D) nanostructured sheets based photocatalyst (mpg-C.sub.3N.sub.xNi) wherein x is in a range of 3 to 4, exhibiting solar hydrogen at the rate ranging from 200000 molg.sup.1h.sup.1 to 1000000 molg.sup.1h.sup.1 under sunlight, comprising the steps of: [0042] i. adding carbon and nitrogen source (precursor) species in a Ludox solution to obtain the reaction precursor with the concentration ratio of 2:3 to 2:6; [0043] ii. adding etchant ammonium hydrogen difluoride with the concentration ranging from 2-5 M to the reaction precursor for removing the Ludox template used to incorporate microporosity followed by washing to obtain mesoporous mpg-C.sub.3Nx; [0044] iii. adding Nickel source (precursor) species at different concentrations (in the range of 0.15 mM to 0.60 mM) in ethylene glycol and subsequently to the product obtained at step (iii) wherein the Ni concentration in a range of 2 to 10% with respect to weight of in the mesoporous mpg-C.sub.3N.sub.x to obtain a first mixture;

[0045] iv. adding sodium hydroxide with a hydrazine source in a volume ratio in a range of 1:30 to 1:300 into the first mixture and allowing to reflux at 65 C. for 5 hours to obtain a reaction mixture; and [0046] v. microwave heat treatment of the solution as obtained in step (iv) for a period in the range of 10 minutes to 30 minutes at a temperature in a range of 120-150 C. to obtain atomically dispersed Ni modified mpg-C.sub.3N.sub.x.

[0047] In another approach, stock solutions of Nickel chloride hexahydrate (NiCl.sub.2.Math.6H.sub.2O) were prepared using different concentrations (e.g., 0.15 mM to 0.60 mM) in ethylene glycol and as-synthesized mpg-C.sub.3N.sub.x and subjected to reflux for 3 hours while stirring. It was then mixed with hydrazine (different amount ranging from 4 L to 19 L) in aqueous NaOH solution allowed to age at 65 C. for 2 hours while stirring. Nickel nanocrystals modified mpg-C.sub.3N.sub.x were washed and centrifuged repeatedly with ethanol and dried overnight at 60 C. The formation of atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.x was confirmed by the XRD and XPS. The atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi exhibits drastically enhanced solar hydrogen at a rate of up to 300000 molg.sup.1h.sup.1 under sunlight.

[0048] The present invention provides formation of atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi, synthesized by varying concentration of Ni precursor (NiCl.sub.2.Math.6H.sub.2O) from 0.30 to 1.2 g.

[0049] The present invention provides the solar hydrogen generation using the atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi, undertaken using different amount of the photocatalysts (mpg-C.sub.3N.sub.xNi) [3 to 5 mg]

[0050] The solar hydrogen generation using the atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi is undertaken with and without using the electron donors (DI water, TEA, TEOA etc.)

[0051] The present invention provides a simple, low cost and one pot process for the formation of mpg-C.sub.3N.sub.xNi, exhibiting excellent solar hydrogen at the rate ranging from 200000 molg.sup.1h.sup.1 to 1000000 molg.sup.1h.sup.1 under sunlight, depending upon photocatalyst synthesis route. It is very stable and exhibit continuous solar hydrogen generation for days (4) without any significant loss in activity.

[0052] The present invention provides a process for preparation of mpg-C.sub.3N.sub.xNi as disclosed herein, wherein said catalyst is useful to develop the renewable hydrogen generation device using the solar radiation.

[0053] The present invention provides a process for preparation of mpg-C.sub.3N.sub.xNi as disclosed herein, wherein said catalyst is useful to develop the renewable hydrogen generation device that can run the mini fan using the hydrogen fuel cell under direct sunlight, when the fuel cell is provided hydrogen being produced therein.

[0054] Although the present disclosure has been described in considerable detail with reference to certain embodiments and implementations thereof, other embodiments are possible to cover the modifications and variations of the present disclosure.

EXAMPLES

[0055] The following examples, which include preferred embodiments, will serve to illustrate the practice of this invention, it being understood that the particulars shown are by way of example and for purpose of illustrative discussion of preferred embodiments of the invention.

Example 1: Process for the Preparation of Nanocrystals Modified (2-D) Nanostructured Sheets Based Heterostructured Photocatalysts and the Atomically Dispersed Ni Modified Catalyst mpg-C.SUB.3.N.SUB.x.Ni

[0056] The present example provides a facile process for synthesizing single site catalyst mpg-C.sub.3N.sub.xNi by a single pot modification by microwave treatment of mpg-C.sub.3N.sub.x mixed with Ni precursor at 150 C. from 10 minutes to 30 minutes. The nitrogen deficient mesoporous carbon nitride (mpg-C.sub.3N.sub.x) was synthesized by adding the rational choice of uncommon carbon and nitrogen source precursor cyanamide (12 g), in Ludox solution (15 ml, HS-40, 40 wt %) as template to introduce porosity. Nitrogen deficiency was created by heating under controlled atmosphere to obtain a reaction precursor. The Ludox template used to introduce microporosity was removed by adding etchant ammonium hydrogen difluoride with the concentration ranging from 2-5 M to the reaction precursor followed by washing to obtain a mesoporous mpg-C.sub.3Nx.

Example 2

[0057] To 20 ml of ethylene glycol, 0.144 g of Nickel (II) chloride (NiCl.sub.2.Math.6H.sub.2O) was added and sonicated for 30 minutes to obtain a homogeneous mixture. To the homogeneous mixture, 0.06 g of mpg-C.sub.3N.sub.x was added and kept in microwave set at 150 C. for 10 minutes to obtain a solution. To this solution, 19 L of hydrazine monohydrate and 600 l of 1M NaOH were added. The resulting sediment was repeatedly washed and centrifuged with DI (deionized) water followed by drying at 60 C. The proportion of Ni in the Ni@mpg-C.sub.3N.sub.x catalyst synthesis was about 0.60 mM.

Example 3

[0058] To 20 ml of ethylene glycol, 0.144 g of Nickel (II) Chloride (NiCl.sub.2.Math.6H.sub.2O) was added and sonicated for 30 minutes to obtain a homogeneous mixture. To the homogeneous mixture, 0.06 g of mpg-C.sub.3N.sub.x was added and kept in microwave set at 150 C. for 10 minutes. To that solution, 16 L of Hydrazine monohydrate and 600 l of 1M NaOH were added. The resulting sediment was repeatedly washed and centrifuged with DI water followed by drying at 60 C. The proportion of Ni in the Ni@mpg-C.sub.3N.sub.x catalyst synthesis was about 0.60 mM.

Example 4

[0059] To 20 ml of ethylene glycol, 0.72 g of Nickel (II) Chloride (NiCl.sub.2.Math.6H.sub.2O) was added and sonicated for 30 minutes to obtain a homogeneous mixture. To the homogeneous mixture, 0.06 g of mpg-C.sub.3N.sub.x was added and kept in microwave set at 150 C. for 10 minutes. To this solution, 8 L of Hydrazine monohydrate and 600 l of 1M NaOH were added to obtain a reaction mixture and allowed to reflux at 65 C. for 5 hours. The resulting sediment was repeatedly washed and centrifuged with DI water and kept for drying at 60 C. The proportion of Ni in the Ni@mpg-C.sub.3N.sub.x catalyst synthesis was about 0.30 mM.

Example 5

[0060] To 20 ml of ethylene glycol, 0.72 g of Nickel (II) Chloride (NiCl.sub.2.Math.6H.sub.2O) was added and sonicated for 30 minutes to obtain a homogeneous mixture. To the homogeneous mixture, 0.06 g of (mpg-C.sub.3N.sub.x)was added and kept in microwave set at 150 C. for 20 minutes. To this solution, 8 l of Hydrazine monohydrate and 600 l of 1M NaOH were added. The resulting sediment was repeatedly washed and centrifuged with DI water followed by drying at 60 C. The proportion of Ni in the Ni@mpg-C.sub.3N.sub.x catalyst synthesis was about 0.30 Mm.

Example 6

[0061] To 20 ml of ethylene glycol, 0.36 g of Nickel (II) Chloride (NiCl.sub.2.Math.6H.sub.2O) was added and sonicated for 30 minutes to obtain a homogeneous mixture. To the homogeneous mixture, 0.06 g of (mpg-C.sub.3N.sub.x) was added and kept in microwave set at 150 C. for 10 minutes. To this solution, 4 L of Hydrazine monohydrate and 600 l of 1M NaOH were added. The resulting sediment was repeatedly washed and centrifuged with DI water followed by drying at 60 C. The proportion of Ni in the Ni@mpg-C.sub.3N.sub.x catalyst synthesis was about 0.15 mM.

Example 7

[0062] To 20 ml of ethylene glycol, 0.18 g of Nickel (II) Chloride (NiCl.sub.2.Math.6H.sub.2O) was added and sonicated for 30 minutes to obtain a homogeneous mixture. To the homogeneous mixture, 0.06 g of (mpg-C.sub.3N.sub.x) was added and kept in microwave set at 150 C. for 10 minutes. To this solution, 4 L of Hydrazine monohydrate and 600 l of 1M NaOH were added. The resulting sediment was repeatedly washed and centrifuged with DI water followed by drying at 60 C. The proportion of Ni in the Ni@mpg-C.sub.3N.sub.x catalyst synthesis was about 0.15 mM.

[0063] In another approach, stock solutions of Nickel chloride hexahydrate (NiCl.sub.2.Math.6H.sub.2O) were prepared using different concentrations (e.g., 0.15 mM to 0.60 mM) in ethylene glycol and as-synthesized mpg-C.sub.3N.sub.x. The stock solutions were subjected to reflux for 3 hours while stirring. It was then mixed with hydrazine (different amounts ranging from 4 L to 19 L) in aqueous NaOH solution and allowed to age at 65 C. for 2 hours while stirring. Nickel nanocrystals modified mpg-C.sub.3N.sub.x were washed and centrifuged repeatedly with ethanol. Finally, these were dried overnight at 60 C.

[0064] Example 8

[0065] To obtain a homogenous mixture, 0.144 g of Nickel (II) Chloride was added to 20 ml of ethylene glycol and stirred for 30 minutes. After adding 0.06 grams of (mpg-C.sub.3N.sub.x) to the homogenous mixture, it was allowed to stir at a temperature of 60 C. for 3 h. It was then mixed with hydrazine followed by which 19 l of hydrazine monohydrate and 600 l of 1M NaOH were added to the solution. Nickel nanocrystals modified mpg-C.sub.3N.sub.x were washed and centrifuged repeatedly with ethanol and dried overnight at 60 C. The proportion of Ni in the mpg-C.sub.3N.sub.x catalyst synthesis was about 0.60 mM.

Example 9

[0066] To obtain a homogenous mixture 0.72 g of Nickel (II) Chloride was added to 20 ml of ethylene glycol and stirred for 30 minutes. After adding 0.06 grams of (mpg-C.sub.3N.sub.x) to the homogenous mixture, it was allowed to stir at a temperature of 60 C. for 3 h. To this solution 8 l of hydrazine monohydrate and 600 l of 1M NaOH were added. Nickel nanocrystals modified mpg-C.sub.3N.sub.x were washed and centrifuged repeatedly with ethanol and dried overnight at 60 C. The proportion of Ni in the mpg-C.sub.3N.sub.x catalyst synthesis was about 0.30 mM.

Example 10

[0067] To obtain a homogenous mixture 0.36 g of Nickel (II) Chloride was added to 20 ml of ethylene glycol and stirred for 30 minutes. After adding 0.06 grams of (mpg-C.sub.3N.sub.x) to the homogenous mixture, it was allowed to stir at a temperature of 60 C. for 3 h. It was then mixed with 4 l of hydrazine monohydrate and 600 l of 1M NaOH were added. Nickel nanocrystals modified mpg-C.sub.3N.sub.x were washed and centrifuged repeatedly with ethanol and were dried overnight at 60 C. The proportion of Ni in the mpg-C.sub.3N.sub.x catalyst synthesis was about 0.30 mM.

[0068] Characterization of the Nickel modified mpg-C.sub.3N.sub.x was carried out using x-ray diffraction (XRD) to analyse the formation of phase and crystallinity as shown in FIG. 1. The mpg-C.sub.3N.sub.x samples were analyzed using transmission electron microscope (TEM) for morphological analysis, and energy-dispersive x-ray spectroscopy (EDX) to understand the presence of elements through atomic analysis which is shown in FIG. 2. X-ray photoelectron spectroscopy (XPS) was carried out on the catalysts for analyzing the elemental composition, their concentration and oxidation states of Carbon (a) and Nitrogen (b) that is depicted in FIG. 3. The charge carrier dynamics studies of the catalyst samples were carried out via photoluminescence spectra shown in FIG. 4. Also, the energy gap values of the bare and Ni-decorated C.sub.3N.sub.x were analyzed using Tauc plot shown in FIG. 5.

Example 11

Solar Hydrogen Generation by the Synthesized Atomically Dispersed Ni Modified Catalyst mpg-C.SUB.3.N.SUB.x.Ni

[0069] The atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi exhibited drastically enhanced solar hydrogen at the rate ranging from 200000 molg.sup.1h.sup.1 to 1000000 molg.sup.1h.sup.1 under sunlight, depending upon the synthesis route of photocatalysts.

Example 12

[0070] The prepared catalyst was subjected to hydrogen generation using solar simulator as a light source, and the method specifically comprised the following steps:

[0071] About 3 mg of the atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.x was weighed, followed by adding in a photocatalytic reactor. Subsequently, 5 ml of water was added to the reactor (or in other case 4.5 ml water and then 0.5 ml electron donor from the group of triethylamine (TEA) and triethanolamine (TEOA)). The solution was then subjected to stirring at room temperature, degassing with nitrogen for 30 minutes to remove dissolved oxygen from the photocatalytic reactor was exposed to the solar simulator (equipped with AM 1.5 filter). The hydrogen production was measured at the interval of every 1 hour using the Gas Chromatograph equipment. The solar hydrogen generation using the solar simulator as the light source for the 0.15 mM Solvo-Ni-mpg-C.sub.3N.sub.x (synthesized by solvothermal modification with Ni) and 0.15 mM Micro-Ni-mpg-C.sub.3N.sub.x (microwave assisted modification with Ni) in water with TEOA electron donor, are comparatively shown in FIG. 7.

Example 13

[0072] In another example, the prepared catalyst was subjected to hydrogen generation under the direct sunlight, and the method specifically comprised the following steps:

[0073] 3 mg of the atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.x was weighed, followed by addition to a photocatalytic reactor. Subsequently, water was added and then an electron donor to obtain a mixture. The mixture was then stirred at room temperature, degassing with nitrogen for 30 minutes to remove dissolved oxygen from the photocatalytic reactor followed by exposing it to the direct sunlight (sunlight), and measuring the hydrogen production at the interval of every 1 hour using the Gas Chromatograph equipment. The solar hydrogen generation of the atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi under sunlight was analysed and shown in FIG. 6. Further, the photocatalytic CO.sub.2 reduction to CH.sub.4 using the solar simulator as the light source for the 0.30 mM Solvo-Ni-mpg-C.sub.3N.sub.x (synthesized by solvothermal modification with Ni) was analyzed and depicted in FIG. 8.

ADVANTAGES OF THE INVENTION

[0074] Process for the preparation of atomically dispersed Ni modified (2-D) nanostructured sheets based catalyst mpg-C.sub.3N.sub.xNi by microwave assisted route having one pot, simple synthetic procedure and low operational cost.

[0075] The formation of atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi by microwave route is fast (reaction duration 10 minutes) and less energy intensive. The developed 2-D nanostructured sheets based heterostructured photocatalysts comprises Earth abundant elements and thus are inexpensive.

[0076] The developed atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi exhibit drastically enhanced solar hydrogen at the rate from 200000 molg.sup.1h.sup.1 to 1000000 molg.sup.1h.sup.1 under sunlight by the atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi, depending upon its synthesis route.

[0077] The atomically dispersed Ni modified catalyst mpg-C.sub.3N.sub.xNi catalysts is useful to develop the renewable hydrogen generation device using the solar radiation that run the mini fan using the hydrogen fuel cell under direct sunlight, when the fuel cell is provided hydrogen being produced therein.