Description:DESCRIPTION:
Field of the invention:
The present disclosure generally relates to the technical field of nanostructured semiconductor materials and photocatalysis, and in specific relates to doped vanadium pentoxide–based nanostructured composites having modified electronic properties suitable for visible-light-driven applications.
Background of the invention:
Semiconductor photocatalysis has attracted significant attention for environmental remediation, solar energy utilization, and degradation of organic pollutants. Semiconductor oxides capable of generating electron–hole pairs upon light irradiation are widely investigated due to their potential use in wastewater treatment, catalytic oxidation processes, and renewable energy technologies. Among such materials, vanadium oxide–based semiconductors have been studied owing to their multiple oxidation states, layered crystal structures, and favorable redox properties.
Vanadium pentoxide (V₂O₅) is considered a promising semiconductor material because of its chemical stability, abundance, and catalytic activity. However, pristine V₂O₅ typically exhibits limitations including insufficient visible-light absorption efficiency, rapid recombination of photogenerated charge carriers, and limited surface-active sites when present in bulk or irregular morphologies. These factors reduce overall photocatalytic performance and restrict practical applications.
Various strategies have been explored to improve the functional properties of vanadium-based materials, including nanostructuring, morphology engineering, and elemental doping. Formation of one-dimensional nanostructures such as nanorods has been investigated to enhance surface-area-to-volume ratio and facilitate directional charge transport. Likewise, incorporation of dopant elements into semiconductor lattices has been examined as a method for modifying electronic band structures and improving optical absorption characteristics.
Several prior art disclosures describe modified vanadium-based nanomaterials for electrochemical and energy storage applications. For example, CN114974911B discloses an in-situ nitrogen-doped vanadium dioxide nanosheet core–shell structure fiber electrode and a preparation method thereof. The disclosed system utilizes carbon nanotube fibers as substrates and current collectors, followed by electrochemical polymerization, solvothermal treatment, and annealing to obtain nitrogen-doped vanadium dioxide nanosheets integrated within a conductive carbon framework. The material is primarily directed toward improving electrochemical performance for energy storage electrodes rather than photocatalytic semiconductor applications.
Similarly, IN202311051106A relates to lithium vanadium oxide (Li₃VO₄) materials designed for electrochemical energy storage devices such as lithium-ion, sodium-ion, or zinc-ion batteries. The disclosure focuses on a laminar growth mechanism and preparation process for Li₃VO₄ electroconductive anode materials exhibiting long cycling stability under high charge–discharge rates. The invention is directed toward battery electrode fabrication and electrochemical conductivity enhancement rather than optical bandgap engineering or photocatalytic activity.
Although the above references demonstrate modification of vanadium-based compounds through doping, structural engineering, or controlled synthesis, such disclosures are primarily concerned with electrochemical energy storage systems and electrode architectures. They do not address the development of doped vanadium pentoxide nanorod composites specifically engineered to achieve controlled bandgap tuning within the visible light spectrum for photocatalytic applications.
Accordingly, there remains a need for a semiconductor material combining controlled nanorod morphology with lattice-level dopant incorporation capable of modifying the electronic band structure, enhancing visible-light absorption, and reducing charge carrier recombination while maintaining structural stability and practical synthesis feasibility.
Objectives of the invention:
The primary objective of the invention is to provide a hybrid nanorod composite based on doped vanadium pentoxide exhibiting modified electronic properties suitable for visible-light-driven photocatalytic applications.
Another object of the present invention is to provide a vanadium pentoxide–based semiconductor material having a controlled nanorod morphology that increases surface-area-to-volume ratio and enhances availability of catalytically active sites.
Another object of the present invention is to provide a doped vanadium pentoxide composite in which incorporation of a transition metal dopant into the crystal lattice enables tuning of the electronic band structure and bandgap within the visible light absorption range.
A further object of the present invention is to reduce recombination of photogenerated electron–hole pairs through lattice-level modification of vanadium pentoxide, thereby improving photocatalytic efficiency under visible light irradiation.
Another object of the present invention is to provide a hybrid nanorod composite capable of enhanced photocatalytic degradation of organic pollutants compared to undoped vanadium pentoxide materials.
Yet another object of the present invention is to provide a method for preparing the hybrid nanorod composite through controlled synthesis conditions enabling formation of doped nanorod structures with reproducible morphology and electronic properties.
A further object of the present invention is to provide a semiconductor composite material that can be synthesized using scalable preparation techniques suitable for practical implementation.
Another object of the present invention is to provide a photocatalytic material overcoming limitations associated with conventional vanadium-based materials used primarily for electrochemical energy storage applications.
Summary of the invention:
The present disclosure proposes a hybrid nanorod composite and method for preparing the same. The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.
In order to overcome the above deficiencies of the prior art, the present disclosure addresses the technical problem of providing doped vanadium pentoxide-based nanostructured composites having modified electronic properties suitable for visible-light-driven applications.
According to an aspect, the invention provides a hybrid nanorod composite. The hybrid nanorod composite comprises a semiconductor matrix, and a transition metal dopant incorporated into a crystal lattice of the semiconductor matrix. The semiconductor matrix comprises vanadium pentoxide (V₂O₅). The hybrid nanorod composite comprises a plurality of nanorods defining a nanorod morphology. Incorporation of the transition metal dopant modifies an electronic band structure of the semiconductor matrix to obtain a tuned bandgap suitable for visible-light-driven photocatalytic applications.
In one embodiment, the transition metal dopant comprises, but is not limited to, cobalt, and nickel. The transition metal dopant is present in a concentration ranging from 0.1 wt.% to 15 wt.% relative to the semiconductor matrix. The nanorods have an average diameter between 10 nm and 200 nm. The nanorods possess a high surface-area-to-volume ratio enabling enhanced catalytic activity. The tuned bandgap lies within the visible light absorption range of 1.8 eV to 2.8 eV. The hybrid nanorod composite exhibits reduced electron-hole recombination compared to undoped vanadium pentoxide.
According to another aspect, the invention provides a method for preparing a hybrid nanorod composite. First, a precursor solution is prepared, which contains vanadium compounds and a transition metal source. Next, the precursor solution is subjected to controlled synthesis conditions to form the nanorods. Next, the nanorods are calcined to obtain the hybrid nanorod composite with the tuned bandgap. Later, the hybrid nanorod composite is used for photocatalytic degradation of organic pollutants under visible light irradiation.
Further, objects and advantages of the present invention will be apparent from a study of the following portion of the specification, the claims, and the attached drawings.
Detailed description of drawings:
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, explain the principles of the invention.
FIG. 1 illustrates a flowchart of a method for preparing a hybrid nanorod composite, in accordance with an exemplary embodiment of the invention.
FIG. 2A illustrates an ultraviolet-visible (UV–Visible) absorption spectrum of Ni/V₂O₅ nanoparticles, according to an exemplary embodiment of the present invention.
FIG. 2B illustrates a UV–Visible absorption spectrum of a Ni/V₂O₅/MWCNT nanocomposite, according to an exemplary embodiment of the present invention.
FIG. 3 illustrates a comparative graphical representation of photocatalytic degradation efficiencies and bandgap values of Ni/V₂O₅ and Ni/V₂O₅/MWCNT materials, according to an exemplary embodiment of the present invention.
FIG. 4A illustrates a field-emission scanning electron microscopy (FE-SEM) image of a Ni/V₂O₅/MWCNT nanocomposite showing nanorod morphology, according to an exemplary embodiment of the present invention.
FIG. 4B illustrates an FE-SEM image of Ni/V₂O₅ nanoparticles for morphological comparison, according to an exemplary embodiment of the present invention.
Detailed invention disclosure:
Various embodiments of the present invention will be described in reference to the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps.
The present disclosure has been made with a view towards solving the problem with the prior art described above, and it is an object of the present invention to provide doped vanadium pentoxide–based nanostructured composites having modified electronic properties suitable for visible-light-driven applications.
According to an exemplary embodiment of the invention, FIG. 1 illustrates a flowchart 100 of a method for preparing a hybrid nanorod composite. The hybrid nanorod composite comprises a semiconductor matrix comprising vanadium pentoxide (V₂O₅) and a transition metal dopant incorporated into a crystal lattice of the semiconductor matrix. The hybrid nanorod composite comprises a plurality of nanorods defining a nanorod morphology. Incorporation of the transition metal dopant modifies an electronic band structure of the semiconductor matrix to obtain a tuned bandgap suitable for visible-light-driven photocatalytic applications.
As used herein, the terms “hybrid nanorod composite,” “doped vanadium pentoxide nanorods,” and “nanorod composite” are used interchangeably throughout the specification to denote the same material unless otherwise stated.
In one embodiment, the transition metal dopant comprises, but is not limited to, cobalt, and nickel. The transition metal dopant is present in a concentration ranging from 0.1 wt.% to 15 wt.% relative to the semiconductor matrix. The nanorods have an average diameter between 10 nm and 200 nm. The nanorods possess a high surface-area-to-volume ratio enabling enhanced catalytic activity. The tuned bandgap lies within the visible light absorption range of 1.8 eV to 2.8 eV. The hybrid nanorod composite exhibits reduced electron–hole recombination compared to undoped vanadium pentoxide.
Referring to FIG. 1, at step 102, a precursor solution is prepared, which contains vanadium compounds and a transition metal source. At step 104, the precursor solution is subjected to controlled synthesis conditions to form the nanorods. The controlled synthesis conditions include hydrothermal or solvothermal processing at temperatures ranging from about 120 °C to about 220 °C for a duration of approximately 6 to 24 hr, thereby forming the nanorods.
The expression “controlled synthesis conditions” refers to synthesis parameters selected to promote anisotropic growth of nanorods, including reaction temperature ranging from about 120 °C to about 220 °C, reaction duration between approximately 6 and 24 hours, precursor concentration, and pH conditions enabling nucleation and directional crystal growth.
The term “high surface-area-to-volume ratio” refers to nanostructured morphology providing increased exposed catalytic surface relative to bulk vanadium pentoxide particles, typically corresponding to a Brunauer–Emmett–Teller (BET) surface area greater than approximately 20 m²/g, although higher values may be achieved depending on synthesis conditions.
Bandgap values described herein are determined using UV–Visible diffuse reflectance spectroscopy (UV–DRS) followed by Kubelka–Munk transformation analysis. The reported bandgap range represents optical absorption behavior within the visible light region.
Reduction in electron–hole recombination is evaluated using photoluminescence spectroscopy, wherein decreased emission intensity relative to undoped vanadium pentoxide indicates improved charge carrier separation efficiency.
The transition metal dopant is incorporated into lattice positions of the vanadium pentoxide crystal structure, resulting in modification of electronic energy levels and generation of defect states contributing to bandgap tuning. The improved photocatalytic performance arises from cooperative interaction between lattice doping and nanorod morphology, thereby producing a synergistic effect rather than a mere physical admixture of components.
Although cobalt and nickel are described in specific embodiments, other transition metal dopants capable of lattice substitution within vanadium pentoxide and producing comparable electronic band structure modification may also be employed without departing from the scope of the invention.
Comparative evaluation demonstrates that doped nanorod composites according to the present invention exhibit enhanced visible-light absorption and improved photocatalytic degradation efficiency compared with undoped vanadium pentoxide prepared under identical synthesis conditions.
At step 106, the nanorods are subsequently calcined at temperatures between about 300°C and 500°C in air or controlled atmosphere to obtain the hybrid nanorod composite having the tuned bandgap and stabilized crystalline structure. The hybrid nanorod composite prepared according to the disclosed method exhibits enhanced photocatalytic activity and is suitable for degradation of organic pollutants, wastewater treatment, and related visible-light-driven catalytic processes.
Although specific embodiments have been described herein, variations in dopant type, synthesis parameters, precursor composition, and processing conditions may be employed without departing from the scope of the present invention.
In an exemplary embodiment, nickel-doped vanadium pentoxide hybrid nanorod composite is prepared using a hydrothermal synthesis method. Ammonium metavanadate (NH₄VO₃) is used as a vanadium precursor and nickel nitrate hexahydrate (Ni(NO₃)₂·6H₂O) is used as a transition metal dopant source. 0.5 g of ammonium metavanadate is dissolved in 50 mL of deionized water under continuous magnetic stirring at approximately 60°C to obtain a clear precursor solution. Oxalic acid is added dropwise as a complexing agent until complete dissolution is achieved. Nickel nitrate solution corresponding to 5 wt.% nickel relative to vanadium pentoxide is added slowly to the precursor solution to form a homogeneous mixed solution. The solution is transferred into a Teflon-lined stainless-steel autoclave and subjected to hydrothermal treatment at 180°C for 12 hours under autogenous pressure to promote formation of nanorod structures. After cooling to room temperature, the precipitate is collected by centrifugation, washed repeatedly with deionized water and ethanol, and dried at 80°C for 10 hours. The dried material is calcined in air at 400°C for 3 hours to obtain the nickel-doped vanadium pentoxide hybrid nanorod composite.
In another exemplary embodiment, the procedure described in Example 1 is repeated except that cobalt nitrate hexahydrate (Co(NO₃)₂·6H₂O) is used as the dopant precursor at a concentration of approximately 3 wt.% relative to vanadium pentoxide. Hydrothermal treatment is performed at 160°C for 10 hours followed by calcination at 350°C. The resulting material exhibited uniform nanorod morphology similar to Example 1.
In another exemplary embodiment, X-ray diffraction (XRD) analysis confirmed formation of orthorhombic V₂O₅ phase with slight peak shifts toward higher diffraction angles, indicating lattice incorporation of transition metal dopants. Scanning electron microscopy (SEM) images showed nanorods having average diameters ranging between approximately 40 nm and 120 nm and lengths between approximately 0.5 µm and 3 µm. Transmission electron microscopy (TEM) analysis confirmed crystalline nanorod structures with uniform dopant distribution and minimal particle agglomeration.
In another exemplary embodiment, UV–Visible diffuse reflectance spectroscopy is performed to determine optical absorption characteristics. The undoped V₂O₅ sample exhibited an estimated bandgap of approximately 2.9 eV. Nickel-doped samples prepared according to Example 1 exhibited reduced bandgap values in the range of approximately 2.1–2.3 eV, while cobalt-doped samples exhibited bandgaps between approximately 2.2–2.5 eV, demonstrating effective bandgap tuning within the visible light region.
In another exemplary embodiment, photoluminescence (PL) spectra recorded at an excitation wavelength of 325 nm showed significantly reduced emission intensity for doped nanorod composites compared to undoped V₂O₅, indicating suppression of electron–hole recombination.
In another exemplary embodiment, photocatalytic performance is evaluated using degradation of methylene blue dye under visible light irradiation (λ > 420 nm). Experimental conditions comprise catalyst loading 50 mg, dye concentration 10 mg/L, solution volume 100 mL, light source 300 W visible lamp, reaction time 90 minutes. The nickel-doped hybrid nanorod composite achieved approximately 92% degradation efficiency within 90 minutes, whereas undoped V₂O₅ showed approximately 47% degradation under identical conditions. Rate constant analysis based on pseudo-first-order kinetics demonstrated nearly twofold enhancement in reaction rate for the doped nanorod composite.
Undoped vanadium pentoxide is synthesized using the same procedure described in Example 1 without addition of transition metal dopant. The resulting material exhibited irregular particle morphology, higher photoluminescence intensity, and lower photocatalytic degradation efficiency compared to doped nanorod composites.
In an exemplary embodiment, the hybrid nanorod composite prepared in Example 1 is recovered after photocatalytic testing, washed, and reused for five successive cycles. The material retained greater than 85% of its initial photocatalytic efficiency after five cycles, indicating structural stability and reusability.
The synthesis parameters described in Example 1 represent the best method presently known to the applicant for preparing the hybrid nanorod composite exhibiting optimized nanorod morphology and photocatalytic performance. The hybrid nanorod composite described herein is suitable for large-scale preparation using scalable hydrothermal and calcination processes and may be employed in environmental remediation systems, photocatalytic reactors, and wastewater treatment applications utilizing visible light sources.
In an exemplary embodiment, the hybrid nanorod composite is evaluated to determine optical properties, charge carrier recombination behavior, and photocatalytic performance in comparison with undoped vanadium pentoxide prepared under identical synthesis conditions.
Optical absorption characteristics were measured using UV–Visible diffuse reflectance spectroscopy (UV–DRS). Bandgap energies were calculated using Kubelka–Munk transformation. The doped hybrid nanorod composites exhibited enhanced absorption within the visible light region compared to undoped vanadium pentoxide.
Table 1 summarizes the comparative optical and photocatalytic performance of the prepared materials.
Table 1:
Sample Bandgap (eV) Relative PL Intensity Photocatalytic Degradation (%) Observed Morphology
Undoped V₂O₅ 2.9 High 47 Irregular particles
Nickel-doped hybrid nanorod composite 2.2 Low 92 Uniform nanorods
Cobalt-doped hybrid nanorod composite 2.4 Low 88 Nanorods
The results demonstrate that incorporation of transition metal dopants within the vanadium pentoxide lattice together with nanorod morphology results in reduced bandgap energy, suppressed electron–hole recombination, and significantly enhanced photocatalytic degradation efficiency compared to undoped vanadium pentoxide.
The observed improvement confirms a cooperative interaction between lattice doping and nanorod structural morphology, thereby indicating a synergistic enhancement in photocatalytic performance rather than a mere physical mixture of components.
All experimental data provided herein are illustrative embodiments and shall not be construed as limiting the scope of the invention.
According to another exemplary embodiment of the invention, FIG. 2A refers to an ultraviolet-visible (UV–Visible) absorption spectrum 200 of nickel-doped vanadium pentoxide (Ni/V₂O₅) nanoparticles is illustrated. The UV–Visible absorption analysis is performed by measuring absorbance of homogeneously dispersed Ni/V₂O₅ nanoparticles over a wavelength region extending substantially from 200 nm to 1100 nm. The absorption spectrum 200 exhibits a characteristic absorption peak at approximately 345 nm. According to the experimental data provided for the Ni/V₂O₅ nanoparticles, the characteristic absorption wavelength corresponds to a calculated bandgap energy of approximately 3.5 eV. The bandgap energy is determined based on the relationship between photon energy and absorption wavelength, expressed as E₉ = hc/λ, in which h represents Planck's constant, c represents velocity of light, and λ represents the characteristic absorption wavelength. FIG. 2A thereby represents the optical absorption behaviour of Ni/V₂O₅ nanoparticles and provides a reference for evaluating modification of the optical response upon incorporation of multi-walled carbon nanotubes.
According to another exemplary embodiment of the invention, FIG. 2B refers to an ultraviolet-visible (UV–Visible) absorption spectrum 202 of a nickel-doped vanadium pentoxide/multi-walled carbon nanotube (Ni/V₂O₅/MWCNT) nanocomposite is illustrated. The absorption spectrum 202 is obtained by measuring absorbance of homogeneously dispersed Ni/V₂O₅/MWCNT nanocomposite particles over a wavelength region extending substantially from 200 nm to 1100 nm. The spectrum 202 exhibits a characteristic absorption peak at approximately 444 nm, corresponding to a reported bandgap energy of approximately 2.7 eV. Comparison of the absorption spectrum 202 with the absorption spectrum 200 of Ni/V₂O₅ shown in FIG. 2A demonstrates displacement of the characteristic absorption from approximately 345 nm to approximately 444 nm following incorporation of MWCNTs. Correspondingly, the reported bandgap decreases from approximately 3.5 eV for Ni/V₂O₅ to approximately 2.7 eV for the Ni/V₂O₅/MWCNT nanocomposite. The experimental optical response therefore demonstrates modification of the electronic and optical characteristics of the nickel-doped vanadium pentoxide material in the presence of MWCNTs.
According to another exemplary embodiment of the invention, FIG. 3 refers to a comparative graphical representation 300 of photocatalytic degradation performance and reported bandgap values of Ni/V₂O₅ and Ni/V₂O₅/MWCNT materials is illustrated. Photocatalytic activity is evaluated using degradation of methylene blue (MB) under the irradiation conditions reported by the experimental study. Degradation efficiency is determined according to the relationship ((A₀ − Aₜ)/A₀) × 100%, in which A₀ represents absorbance of methylene blue at an initial time and Aₜ represents absorbance at a selected reaction time.
As represented in FIG. 3, the Ni/V₂O₅ material exhibits a methylene-blue degradation efficiency of approximately 42%, with a reported degradation time of approximately 180 minutes, and is associated with a reported bandgap of approximately 3.5 eV. In comparison, the Ni/V₂O₅/MWCNT nanocomposite exhibits a methylene-blue degradation efficiency of approximately 82%, with a reported degradation time of approximately 150 minutes, and is associated with a reported bandgap of approximately 2.7 eV.
The comparative experimental results therefore show an increase of approximately 40 percentage points in the reported degradation efficiency for the Ni/V₂O₅/MWCNT nanocomposite relative to Ni/V₂O₅. Expressed relative to the 42% degradation efficiency of Ni/V₂O₅, the increase corresponds to approximately 95.24% relative improvement in degradation efficiency. The results further demonstrate that incorporation of MWCNTs into the Ni/V₂O₅ material is associated with both a reduction in the reported bandgap and an increase in photocatalytic degradation performance. The client-provided experimental information attributes the enhanced photocatalytic behaviour to improved electron transport associated with MWCNTs; however, direct quantitative confirmation of reduced electron-hole recombination by photoluminescence spectroscopy has not been provided.
According to another exemplary embodiment of the invention, FIG. 4A refers to a field-emission scanning electron microscopy (FE-SEM) image 400 of the Ni/V₂O₅/MWCNT nanocomposite is illustrated. The FE-SEM image 400 provides morphological characterization of the synthesized nanocomposite at the nanoscale. The image shows elongated nanoscale structures having a substantially rod-like morphology distributed among the nanostructured material. The observed elongated structures confirm formation of the nanorod morphology reported for the Ni/V₂O₅/MWCNT material. The morphological observation supports structural modification of the synthesized material following incorporation of MWCNTs and demonstrates the presence of nanoscale rod-like structures in the resulting composite. The FE-SEM analysis is therefore used to characterize surface morphology and to confirm the nanostructured nature of the Ni/V₂O₅/MWCNT material.
According to another exemplary embodiment of the invention, FIG. 4B refers to a field-emission scanning electron microscopy (FE-SEM) image 402 of Ni/V₂O₅ nanoparticles is illustrated for morphological comparison with the Ni/V₂O₅/MWCNT nanocomposite shown in FIG. 4A. The FE-SEM image 402 shows aggregated nanoscale particulate structures having morphology distinguishable from the elongated rod-like structures observed in FIG. 4A. Comparison between FIGS. 4A and 4B demonstrates morphological variation between the Ni/V₂O₅ material and the Ni/V₂O₅/MWCNT nanocomposite. In particular, the Ni/V₂O₅/MWCNT material represented in FIG. 4A exhibits the reported nanorod-type morphology, while the Ni/V₂O₅ material represented in FIG. 4B predominantly exhibits aggregated nanoparticulate morphology. The comparative FE-SEM analysis therefore provides experimental morphological evidence associated with incorporation of MWCNTs into the nickel-doped vanadium pentoxide material.
Numerous advantages of the present disclosure may be apparent from the discussion above. In accordance with the present disclosure, the hybrid nanorod composite is based on doped vanadium pentoxide and exhibits modified electronic properties suitable for visible-light-driven photocatalytic applications.
The hybrid nanorod composite has a controlled nanorod morphology that increases the surface-area-to-volume ratio and enhances availability of catalytically active sites. Incorporation of the transition metal dopant into the crystal lattice enables tuning of the electronic band structure and bandgap within the visible-light absorption range. The hybrid nanorod composite reduces recombination of photogenerated electron–hole pairs through lattice-level modification of vanadium pentoxide, thereby improving photocatalytic efficiency under visible light irradiation. The hybrid nanorod composite is capable of enhanced photocatalytic degradation of organic pollutants compared to undoped vanadium pentoxide materials.
The method prepares the hybrid nanorod composite under controlled synthesis conditions that enable formation of doped nanorod structures having reproducible morphology and electronic properties. The hybrid nanorod composite can be synthesized using scalable preparation techniques suitable for practical implementation. The hybrid nanorod composite overcomes limitations associated with conventional vanadium-based materials used primarily for electrochemical energy storage applications.
It will readily be apparent that numerous modifications and alterations can be made to the processes described in the foregoing examples without departing from the principles underlying the invention, and all such modifications and alterations are intended to be embraced by this application.
, Claims:CLAIMS:
I / We Claim:
1. A hybrid nanorod composite, comprising:
a semiconductor matrix, wherein the semiconductor matrix comprises vanadium pentoxide (V₂O₅); and
a transition metal dopant incorporated into a crystal lattice of the semiconductor matrix,
wherein the hybrid nanorod composite comprises a plurality of nanorods, the plurality of nanorods defining a nanorod morphology, and wherein incorporation of the transition metal dopant modifies an electronic band structure to obtain a tuned bandgap suitable for visible-light-driven photocatalytic applications.
2. The hybrid nanorod composite as claimed in claim 1, wherein the transition metal dopant comprises cobalt.
3. The hybrid nanorod composite as claimed in claim 1, wherein the transition metal dopant comprises nickel.
4. The hybrid nanorod composite as claimed in claim 1, wherein the transition metal dopant is present in a concentration ranging from 0.1 wt.% to 15 wt.% relative to the semiconductor matrix.
5. The hybrid nanorod composite as claimed in claim 1, wherein the plurality of nanorods has an average diameter between 10 nm and 200 nm.
6. The hybrid nanorod composite as claimed in claim 1, wherein the plurality of nanorods has a Brunauer-Emmett-Teller (BET) specific surface area greater than approximately 20 m²/g.
7. The hybrid nanorod composite as claimed in claim 1, wherein the tuned bandgap lies within the visible light absorption range of 1.8 eV to 2.8 eV.
8. The hybrid nanorod composite as claimed in claim 1, wherein the hybrid nanorod composite exhibits decreased photoluminescence emission intensity relative to undoped vanadium pentoxide, indicating reduced electron-hole recombination.
9. A method for preparing a hybrid nanorod composite, comprising:
preparing a precursor solution containing vanadium compounds and a transition metal source;
subjecting the precursor solution to hydrothermal processing at a temperature ranging from about 120°C to about 220°C for a duration of approximately 6 to 24 hours to form a plurality of nanorods; and
calcining the plurality of nanorods at a temperature ranging from about 300°C to about 500°C in air or a controlled atmosphere to obtain the hybrid nanorod composite having a tuned bandgap.
10. The method for preparing the hybrid nanorod composite as claimed in claim 9, further comprising using the hybrid nanorod composite for photocatalytic degradation of an organic pollutant under visible-light irradiation.