Bismuth Vanadate Nanoparticles: Structure, Synthesis, and Emerging Engineering Applications Volume 62- Issue 3

Muhammad Jamil¹, Ajmal Shah²*, Ghazal Aman², Faiza Shabir², Rainaz Begum², Hao Sun³*, Saima Rafiq², Nasir Iqbal⁴, Nadia Aman², Nabeela Aman⁵, Zainab liaqat⁶ and Seeqal Aleena⁷

• ¹Institute of Chemical Sciences, University of Swat, Pakistan
• ²Department of Chemistry, Abdul Wali Khan University, mardan, Pakistan
• ³Wolfson Institute for Biomedical Research, UCL Division of Medicine, University College London, United Kingdom
• ⁴School of Chemistry, Xi’an Jiaotong University,710049 Xi’an, People’s Republic of China
• ⁵Department of Chemistry, university of swabi, Pakistan
• ⁶Sarhad Institute of Allied Health Sciences. Sarhad University of Science and Information Technology Peshawar, Pakistan
• ⁷Pmas Arid Agriculture University, Rawalpindi, Pakistan

Received: June 25, 2025; Published: July 08, 2025

*Corresponding author: Ajmal Shah, Department of Chemistry, Abdul Wali Khan University, Mardan, Pakistan
Hao Sun, Wolfson Institute for Biomedical Research, UCL Division of Medicine, University College London, United Kingdom

DOI: 10.26717/BJSTR.2025.62.009758

Abstract PDF

Bismuth vanadate (BiVO₄) nanoparticles are gaining momentum in engineering for their visible-light activity, non-toxicity, and stability. With a bandgap around 2.4 eV, BiVO₄ is well-suited for photocatalysis, water splitting, environmental cleanup, and optoelectronics. Advances in synthesis methods have improved control over structure and performance, boosting efficiency in degrading pollutants and generating hydrogen. Despite their potential, BiVO₄ faces hurdles like poor charge transport and limited scalability. Strategies such as doping, heterostructure design, and material integration are being explored to overcome these issues. This review highlights the key properties, synthesis techniques, and engineering applications of BiVO₄ nanoparticles, and outlines the challenges ahead for real-world use (Figure 1).

Keywords: Bismuth Vanadate; Synthesis; Nanoparticles; Degradation; Structure of Bismuth Vanadate

Figure 1

Bismuth vanadate (BiVO₄) is an inorganic semiconductor composed of bismuth (Bi³⁺), vanadium (V⁵⁺), and oxygen [1]. It can crystallize in multiple phases, but the monoclinic scheelite structure is considered the most efficient for photocatalytic applications due to its favorable band structure and high stability [2]. In this phase, the distorted arrangement of VO₄ tetrahedra and BiO₈ dodecahedra enhances both light absorption and charge separation, enabling BiVO₄ to respond effectively to visible light [3]. With a bandgap of approximately 2.4 eV, BiVO₄ absorbs a broad portion of the solar spectrum— unlike traditional UV-active materials such as TiO₂ making it highly promising for solar-driven technologies [4]. The interest in BiVO₄ has grown rapidly due to its potential to address critical engineering challenges in clean energy, environmental remediation, and sustainable device fabrication [5]. One major area of application is photocatalysis, where BiVO₄ nanoparticles have demonstrated strong performance in breaking down organic pollutants in air and water. These include industrial dyes, pharmaceuticals, and volatile organic compounds, making BiVO₄ a strong candidate for advanced wastewater treatment and air purification systems [6]. Another critical application is solar-driven water splitting. By using sunlight to generate hydrogen from water, BiVO₄ enables the production of clean fuel. While pure BiVO₄ faces limitations such as low charge mobility and high recombination rates, modifications like doping and coupling with co-catalysts have significantly improved its performance in this area [7].

Its role as a photoanode in photoelectrochemical (PEC) cells is also well established, offering a stable and efficient interface for solar fuel generation and semi-artificial photosynthesis systems [8]. In the field of optoelectronics, BiVO₄ is being engineered into light-sensitive devices such as photodetectors and gas sensors. Its semiconducting behavior under illumination makes it suitable for detecting changes in the environment, particularly in low-cost, solar-powered sensing platforms [9]. Additionally, BiVO₄ is frequently used in hybrid nanomaterials— combined with substances like graphene, carbon nanotubes, or metal-organic frameworks—to create multifunctional systems for energy storage, flexible electronics, and smart coatings [10]. Despite these promising attributes, several engineering challenges remain. BiVO₄ still suffers from inefficient charge transport, surface recombination, and limitations in large-scale synthesis. Research efforts continue to focus on interface engineering, structural tuning, and scalable fabrication techniques [11]. This review provides a comprehensive overview of BiVO₄ nanoparticles, beginning with their structural and electronic properties, followed by synthesis methods, engineering applications, and recent innovations. It concludes with a discussion on the current challenges and the strategies being explored to translate this promising material from laboratory success to real-world deployment (Figure 2).

Figure 2

Crystal Structure and Polymorphs

Bismuth vanadate (BiVO₄) exists primarily in two polymorphic forms: tetragonal zircon-type and monoclinic scheelite-type. These structures are not just names, they define how the atoms are arranged in three-dimensional space, influencing the material’s properties in fundamental ways [12]. The tetragonal form is typically stable at higher temperatures and is characterized by a more symmetric arrangement. While structurally elegant, this phase shows relatively lower photocatalytic activity, making it less desirable for light-driven applications [13]. In contrast, the monoclinic scheelite structure, stable at room temperature, features a slightly distorted lattice. This distortion enhances charge separation and reduces electron-hole recombination, boosting photocatalytic performance. Most notably, the monoclinic phase demonstrates superior visible-light absorption due to improved orbital overlap between bismuth and oxygen atoms. Interestingly [14], it’s possible to synthesize BiVO₄ nanoparticles in either polymorph depending on the method and conditions used. For example, low-temperature hydrothermal methods often yield the monoclinic phase, while high-temperature solid-state reactions might stabilize the tetragonal form [15]. The structural transition from tetragonal to monoclinic is often reversible and influenced by heat treatment or doping with other elements. These transitions open avenues for tuning properties on demand, which is particularly valuable in designing devices for specific engineering needs [16].

Electronic Band Structure and Bandgap

One of the standout features of BiVO₄ is its electronic band structure, particularly its narrow bandgap of approximately 2.4 eV. But what does that mean for engineers and researchers? The bandgap refers to the energy difference between the valence band (filled with electrons) and the conduction band (where electrons move freely to conduct electricity). A 2.4 eV bandgap places BiVO₄ squarely in the visible light region of the electromagnetic spectrum—unlike TiO₂ (3.2 eV) or ZnO (3.3 eV), which are only UV-active [17]. This makes BiVO₄ a photoactive material under sunlight, capable of initiating redox reactions such as splitting water molecules or degrading organic pollutants. The conduction band is mainly composed of vanadium 3d orbitals, while the valence band gets significant contribution from bismuth 6s and oxygen 2p orbitals. This hybridized structure facilitates better charge carrier mobility, a critical factor for high-efficiency photocatalysis and optoelectronic devices [18]. However, BiVO₄ is not without challenges. Despite its visible light activity, the material suffers from low electron mobility and short charge carrier lifetimes. Scientists often overcome these hurdles by doping with transition metals or coupling with co-catalysts like WO₃ or Co-Pi to improve charge separation. In essence, the unique band structure of BiVO₄ positions it as a frontrunner for sustainable technologies, especially in areas where harnessing visible light is key [19].

Optical, Magnetic, and Thermal Characteristics

Beyond its electronic attributes, BiVO₄ exhibits a suite of fascinating physical properties. Let’s break them down. Optical Properties: BiVO₄ has strong absorption in the visible light range, especially between 400–520 nm. Its high molar absorptivity means it can utilize sunlight more effectively than many of its semiconductor peers. This makes it ideal for photoelectrochemical cells, photocatalytic reactors, and even smart coatings [20]. Magnetic Behavior: Typically, BiVO₄ is diamagnetic, meaning it doesn’t retain magnetic properties when an external field is removed. However, when doped with certain magnetic ions (like Fe or Co), it can exhibit weak paramagnetism, which can be exploited in spintronic devices or magneto-optical sensors [21]. Thermal Characteristics: BiVO₄ is thermally stable up to about 500°C, a trait vital for high-temperature processing in industrial applications. Additionally, its relatively low thermal conductivity helps in retaining heat, which can be beneficial in thermoelectric materials and solar thermal collectors [22]. These physical traits combine to make BiVO₄ an exceptionally versatile material. Whether it’s absorbing sunlight, responding to magnetic fields, or withstanding high temperatures, this nanoparticle stands ready for complex engineering challenges.

Comparison with Other Visible-Light-Active Semiconductors (e.g., TiO₂, ZnO)

TiO₂ and ZnO have dominated the photocatalysis and sensor markets for decades. But the entry of BiVO₄ has changed the game [23- 28]. While TiO₂ and ZnO require UV light activation, BiVO₄ can harness natural sunlight more effectively. That alone gives it a significant edge in solar energy applications, especially in regions with high ambient sunlight. Moreover, BiVO₄’s better alignment of conduction and valence bands makes it a stronger oxidizing agent in photocatalytic processes. That’s why it’s increasingly preferred in applications like water purification, air cleaning, and even green hydrogen production [29] (Table 1).

Table 1: CT Exam Protocol.

The synthesis route plays a critical role in defining the structure, morphology, and functional properties of BiVO₄ nanoparticles [30]. Below is a detailed overview of key synthetic methods, starting with hydrothermal and solvothermal techniques considered foundational for high-performance nanostructures (Figure 3).

Figure 3

Hydrothermal Synthesis

Hydrothermal synthesis is one of the most widely used methods for fabricating BiVO₄ nanoparticles due to its ability to produce highly crystalline materials with controlled morphologies. In this approach, aqueous solutions of bismuth and vanadium precursors—typically Bi(NO₃)₃·5H₂O and NH₄VO₃ or NaVO₃—are placed in a Teflon-lined stainless-steel autoclave and heated to elevated temperatures, usually between 120°C and 220°C, for several hours. The sealed high-pressure environment promotes the solubility and mobility of ionic species, enhancing nucleation and crystal growth [31]. This technique often favors the formation of the monoclinic scheelite phase, particularly under neutral to slightly alkaline pH conditions, which can be adjusted using ammonia or sodium hydroxide. Surfactants such as CTAB or citric acid are sometimes added to further control the particle morphology and reduce agglomeration [32]. Depending on parameters like temperature, time, and pH, hydrothermal synthesis can yield various nanostructures including rods, sheets, and flower-like assemblies. One key advantage of hydrothermal synthesis is its environmental friendliness, as it typically uses water as the solvent. It also offers excellent control over crystal quality and phase purity. However, the method often requires long reaction times (ranging from 6 to 24 hours) and specialized pressure-resistant equipment. Additionally, scale-up can be limited due to the batch nature of the process and potential variability between runs [33] (Figure 4).

Figure 4

Solvothermal Synthesis

Solvothermal synthesis follows a similar principle to hydrothermal processing but substitutes water with organic solvents such as ethanol, ethylene glycol, diethylene glycol, or dimethylformamide (DMF). These solvents can alter the dielectric environment and reaction kinetics, which in turn influence nucleation rates and crystal growth pathways [34]. In this method, bismuth and vanadium precursors are dissolved in the chosen solvent—often with the aid of surfactants or chelating agents to control morphology—and heated in an autoclave at temperatures typically ranging from 100 °C to 200 °C. The use of organic solvents allows for better regulation of particle dispersion and enables the synthesis of more complex or anisotropic nanostructures such as hollow spheres, nanoplates, and dendritic architectures. Solvothermal synthesis is particularly useful when aiming to produce BiVO₄ with uniform particle size distribution and high surface area. The slower nucleation rates in organic media often result in better-controlled crystal growth and reduced aggregation. However, this method also has limitations. Organic solvents can introduce impurities if not thoroughly removed during post-processing, and solvent compatibility with the metal precursors must be carefully managed. Moreover, the need for solvent recovery and environmental handling can complicate large-scale production [35] (Figure 5).

Figure 5

Sol–Gel Method

The sol–gel method offers a molecular-level approach to synthesizing BiVO₄ nanoparticles, providing precise control over stoichiometry, composition, and structural uniformity. In this process, metal precursors such as Bi(NO₃)₃ and NH₄VO₃ are dissolved in a solvent— commonly ethanol or water—alongside a chelating agent like citric acid or ethylene glycol. Through hydrolysis and polycondensation, the system transitions from a stable colloidal “sol” into a gel-like network. Following gelation, the product is typically dried and then calcined at elevated temperatures to remove organic residues and induce crystallization of the BiVO₄ phase. This route is particularly suited for generating nanostructured BiVO₄ with high surface area and controllable porosity—characteristics that are highly desirable in photocatalytic and photoelectrochemical applications. One of the primary strengths of the sol–gel method lies in its ability to achieve excellent compositional homogeneity and fine control over the final microstructure. Furthermore, it is highly adaptable for forming thin films and coatings, offering advantages for device fabrication. However, the process is often time-consuming, involving multiple stages from solution preparation to thermal treatment. The chemistry of the precursors can also be complex, requiring precise control to avoid unwanted side reactions. Additionally, shrinkage and cracking during drying and calcination can lead to defects in the final material, especially in film or monolith formats [36] (Figure 6).

Figure 6

Electrospinning

Electrospinning is a powerful technique for producing one-dimensional BiVO₄ nanostructures, particularly nanofibers and mats, which are valuable for applications requiring high surface area and enhanced charge transport. In this method, a viscous polymer solution incorporating bismuth and vanadium precursors is subjected to a high-voltage electric field. The electric force draws the solution into ultrafine jets that are collected as continuous fibers on a grounded substrate. These composite fibers are then calcined at high temperatures to decompose the polymer and crystallize the embedded BiVO₄ nanoparticles. The resulting fibrous structures possess interconnected porosity and extended surface area, which promote efficient light absorption and reactant diffusion-key features for photocatalytic and sensing technologies. Electrospinning allows for fine control over fiber morphology and diameter by adjusting parameters such as solution viscosity, flow rate, and applied voltage. It is especially useful for producing membranes or electrodes where directional transport and structural stability are needed. However, the method requires careful optimization to achieve uniform fiber formation and avoid defects. Its applicability is somewhat limited to systems that are compatible with polymer-assisted synthesis. Moreover, residual carbon or other impurities from the polymer may remain after calcination if not fully eliminated, potentially affecting the purity and performance of the final product [37] (Figure 7).

Figure 7

Microwave-Assisted Synthesis

Microwave-assisted synthesis has emerged as a rapid and energy- efficient route for preparing BiVO₄ nanoparticles. Unlike conventional heating methods, which rely on thermal conduction from the surface inward, microwave radiation heats the reaction mixture volumetrically. This uniform and accelerated heating significantly shortens synthesis times—from hours to just minutes—and enhances the kinetics of nucleation and crystal growth. In typical procedures, aqueous or organic solutions of Bi and V precursors are irradiated in a microwave reactor under controlled conditions of power and time. The method often yields small, uniformly distributed BiVO₄ nanoparticles with high crystallinity and minimal agglomeration. These characteristics are particularly beneficial for applications such as photocatalysis, where surface area and charge separation efficiency are critical [38]. The advantages of microwave-assisted synthesis include its rapid processing, high energy efficiency, and ability to produce high-quality nanoparticles with relatively simple equipment. However, the technique also presents challenges. It requires microwave-compatible vessels and precise temperature control to prevent localized overheating or decomposition. Moreover, scaling up microwave synthesis from lab-scale to industrial production remains a significant hurdle, as maintaining uniform heating in larger volumes is complex [39] (Figure 8).

Figure 8

Bismuth vanadate is used in different fields of life. Some of the applications of Bismuth vanadate are given below:

Photocatalysis

Photocatalysis is one of the most extensively explored applications of bismuth vanadate (BiVO₄) nanoparticles due to their ability to harness visible light for environmental remediation and solar-driven energy conversion [40]. The monoclinic scheelite phase of BiVO₄, with a direct band gap of approximately 2.4 eV, makes it highly responsive to visible light. Its valence band, primarily derived from O 2p orbitals, enables strong oxidative potential, while its conduction band is suitably positioned for reductive processes. These attributes have made BiVO₄ a promising candidate for applications such as photoelectrochemical (PEC) water splitting and the degradation of organic pollutants. In PEC water splitting, BiVO₄ is typically employed as a photoanode material for the oxygen evolution reaction (OER). Its visible-light absorption and oxidative ability are advantageous; however, its low electron mobility, high recombination rate of photogenerated carriers, and sluggish surface reaction kinetics significantly limit overall efficiency. To overcome these limitations, researchers have employed several material design strategies. Nanostructuring BiVO₄ into architectures like nanoplates, nanorods, and porous films reduces charge transport distances and increases the active surface area. Conductive underlayers such as WO₃ or fluorine-doped tin oxide (FTO) are often used to enhance charge extraction [41]. Additionally, surface modification with OER cocatalysts—such as cobalt phosphate (Co-Pi), FeOOH, or NiFe-layered double hydroxides—has been shown to facilitate charge transfer and improve surface reaction kinetics. Another approach involves doping BiVO₄ with transition metals such as molybdenum (Mo⁶⁺) or tungsten (W⁶⁺), which increases electrical conductivity by introducing shallow donor levels or enhancing carrier density. These modifications have enabled significant improvements in photocurrent densities and stability under simulated sunlight, making BiVO₄ one of the most efficient oxide-based photoanodes developed to date [42].

BiVO₄ also finds extensive application in the photocatalytic degradation of organic pollutants, such as dyes, pharmaceuticals, and emerging contaminants. Under visible-light irradiation, BiVO₄ generates reactive oxygen species (ROS) including hydroxyl radicals (·OH) and superoxide anions (O₂⁻·), which can oxidize organic molecules into less harmful byproducts or completely mineralize them. The efficiency of this degradation process is highly dependent on factors such as crystallinity, surface area, and adsorption capacity of the catalyst [43]. Nanostructured BiVO₄ with a high surface-to-volume ratio enhances light harvesting and provides more active sites for redox reactions. To further boost its photocatalytic performance, BiVO₄ is often integrated into heterojunction systems with other semiconductors such as TiO₂, ZnO, SnO₂, and graphitic carbon nitride (g-C₃N₄). These heterostructures facilitate efficient charge separation by creating internal electric fields and well-aligned band structures, thereby suppressing electron–hole recombination. Depending on the band alignment, either type-II or Z-scheme heterojunctions are constructed. Type-II junctions spatially separate electrons and holes across different semiconductors, while Z-schemes preserve high redox potentials and improve reaction selectivity [44].

In addition to doping and heterostructure design, surface and defect engineering have proven effective in modulating the photocatalytic behavior of BiVO₄. The introduction of oxygen vacancies can improve light absorption and provide new reactive sites, while the use of passivation layers like Al₂O₃ can reduce surface recombination without obstructing charge flow. Incorporating noble metals such as silver, gold, or platinum to form Schottky junctions further enhances performance by serving as electron traps and facilitating interfacial charge transfer. These combined strategies have significantly advanced the functional capabilities of BiVO₄ nanoparticles in photocatalytic systems. With continuing improvements in synthesis precision, surface chemistry, and device integration, BiVO₄ is well-positioned to play a central role in next-generation technologies for clean energy production and environmental sustainability [27].

Remediation

Beyond energy applications, bismuth vanadate (BiVO₄) nanoparticles have shown considerable promise in the field of environmental remediation, particularly for the removal of toxic contaminants from water systems. Their photocatalytic activity under visible light, chemical stability, and tunable electronic structure make them ideal candidates for solar-assisted pollutant degradation and detoxification processes [45]. One major application of BiVO₄ in this context is the removal of heavy metal ions and synthetic dyes from wastewater. These pollutants—originating from industries such as textiles, pharmaceuticals, mining, and electroplating—pose serious ecological and health risks due to their toxicity, persistence, and potential for bioaccumulation. BiVO₄-based photocatalysts, especially in nanoparticle or nanocomposite form, can facilitate the degradation or transformation of such contaminants into less harmful forms. Under visible-light irradiation, BiVO₄ generates reactive oxygen species that break down complex dye molecules into smaller, non-toxic fragments, while simultaneously oxidizing or reducing heavy metal ions such as Cr(VI), Pb(II), or Cd(II) [46]. The efficiency of these photocatalytic degradation processes is influenced by several factors, including particle size, surface area, phase purity, and the presence of surface defects.

High surface-area BiVO₄ nanostructures increase the number of active sites for pollutant adsorption and reaction. Moreover, tailoring the electronic structure through dopants or heterostructure formation can improve the separation of photogenerated carriers and extend the range of active wavelengths into the visible spectrum. Recent efforts have focused on integrating BiVO₄ into solar-driven water purification systems, leveraging its ability to utilize ambient sunlight rather than artificial UV sources. These systems typically involve BiVO₄ immobilized on substrates, incorporated into membranes, or suspended in reactors as a photocatalytic slurry. When exposed to sunlight, the material initiates redox reactions that degrade organic pollutants and reduce metal ions without the need for harsh chemicals or external energy input. To enhance practical performance, BiVO₄ is often combined with co-catalysts or other semiconductors such as g-C₃N₄, ZnO, or Ag₃PO₄. These composites form heterojunctions that facilitate charge separation and broaden the spectral response. Some designs also incorporate magnetic components like Fe₃O₄ to allow easy post-treatment recovery of the catalyst using external magnetic fields, addressing concerns around catalyst reuse and long-term stability [47].

Energy Devices

The use of bismuth vanadate (BiVO₄) nanoparticles in energy devices has gained increasing attention due to their favorable optoelectronic properties, visible-light activity, and compatibility with other functional materials. Among these applications, photoelectrochemical (PEC) cells represent a major area where BiVO₄ has been extensively studied as a photoanode material for solar energy conversion. In PEC systems, BiVO₄ serves as the light-absorbing semiconductor responsible for driving the oxygen evolution reaction (OER) under solar illumination. Its band gap of approximately 2.4 eV enables efficient utilization of visible light, and its valence band position offers a strong oxidizing potential suitable for water oxidation. However, the practical performance of BiVO₄ in PEC devices is hindered by several intrinsic limitations, including low electron mobility, short carrier diffusion lengths, and slow interfacial kinetics [48]. To address these issues, BiVO₄ has been integrated with a variety of materials designed to improve charge separation, enhance conductivity, and stabilize the electrode interface. One widely adopted strategy involves coupling BiVO₄ with carbon-based nanomaterials such as graphene and carbon nanotubes (CNTs). These materials offer high electrical conductivity and large surface area, acting as electron-conducting scaffolds that facilitate rapid charge transport away from the BiVO₄ interface.

The intimate contact between BiVO₄ and carbon supports creates heterointerfaces that reduce recombination losses and promote directional charge flow, significantly enhancing photocurrent densities and overall device efficiency. Other composite strategies include the use of transparent conductive oxides (e.g., indium tin oxide, fluorine- doped tin oxide) and metal oxide underlayers such as WO₃ or TiO₂, which can serve as both physical supports and electron transport channels. In some architectures, BiVO₄ is used in tandem with p-type semiconductors or dye-sensitizers to form Z-scheme systems, enabling simultaneous OER and hydrogen evolution in a single device. Beyond PEC cells, BiVO₄ nanomaterials are also being explored for use in supercapacitors and lithium-ion battery electrodes, where their layered crystal structure and chemical stability provide potential advantages for charge storage. Although research in these areas is still emerging, early results indicate that BiVO₄, especially when hybridized with conductive polymers or carbon nanostructures, can exhibit improved electrochemical stability and capacity retention [49].

Sensors and Optoelectronics

Bismuth vanadate (BiVO₄) nanoparticles are increasingly being investigated for applications in sensors and optoelectronic devices due to their semiconducting nature, visible-light activity, and chemical stability. Their unique combination of photocatalytic and photoresponsive properties makes them suitable for integration into a range of technologies, including gas sensors and light-triggered electronic components.n gas sensing, BiVO₄’s sensitivity to ambient chemical environments is leveraged to detect toxicor flammable gases such as NO₂, NH₃, and H₂S. The sensing mechanism is primarily governed by changes in electrical resistance resulting from gas adsorption on the BiVO₄ surface [50]. Upon interaction with oxidizing or reducing gases, charge carriers in the semiconductor are either withdrawn or injected, leading to measurable shifts in conductivity. Nanostructured BiVO₄, with its high surface area and abundant active sites, enables rapid and selective detection at relatively low operating temperatures. Furthermore, the photocatalytic nature of BiVO₄ can assist in sensor regeneration under light exposure, enhancing device longevity and responsiveness. To improve sensitivity and response time, BiVO₄ is often combined with materials that offer complementary properties. For example, hybrid structures incorporating graphene, ZnO, or carbon nanotubes not only improve electrical conductivity but also introduce additional adsorption sites and facilitate faster charge transfer. These composite materials are particularly effective in forming heterojunctions that amplify the electrical signal changes upon gas exposure. Some designs also utilize plasmonic nanoparticles such as Ag or Au to enhance light absorption and local electric fields, further improving detection sensitivity under visible light [51].

In optoelectronic applications, BiVO₄ is being explored for use in light-sensitive switches, photodetectors, and photoresponsive logic elements. Its ability to generate electron-hole pairs under visible light enables the modulation of current or voltage in response to illumination. Devices based on BiVO₄ thin films or nanostructures can thus function as phototransistors or light-controlled gates, with potential use in optical communication and smart electronics. Efforts to optimize BiVO₄ for these applications often focus on tuning its band structure, enhancing carrier mobility, and engineering defect states that act as charge traps or recombination centers. Doping and interface engineering are critical in this context, as they influence both the optical response and the charge dynamics of the material. Additionally, incorporating BiVO₄ into flexible substrates and microscale device architectures has opened up pathways for developing lightweight, portable, and wearable sensor systems [52].

As research into Bismuth Vanadate (BiVO₄) nanoparticles continues to evolve, translating laboratory breakthroughs into industrial- scale solutions remains both a challenge and an opportunity. Despite significant progress in understanding its crystal structure, electronic properties, and photocatalytic capabilities, the commercial viability of BiVO₄-based systems hinges on addressing key translational gaps. Chief among these is the development of scalable synthesis techniques. Currently, many of the methods used—such as hydrothermal or sol-gel synthesis—are either too time-consuming or cost-intensive for large-scale production. Streamlining these processes without compromising the structural integrity and functional properties of BiVO₄ is critical. Techniques like spray pyrolysis or microwave-assisted synthesis may offer more industrially feasible routes, but they require further optimization and standardization. In parallel, the integration of BiVO₄ into practical engineering applications demands a deeper understanding of its lifecycle—from material sourcing and manufacturing to end-of-life disposal or recycling. A comprehensive lifecycle analysis would illuminate the environmental footprint of BiVO₄ nanoparticles and help guide sustainable engineering practices. This is particularly vital given the growing emphasis on green technologies and circular economy models.

For instance, research into the environmental impact of BiVO₄- based photocatalysts in water treatment or solar fuel generation could inform regulatory frameworks and public policy. Moreover, the interdisciplinary potential of BiVO₄ is just beginning to be tapped. Beyond conventional photocatalysis, its unique optical and electronic properties make it a promising candidate for next-generation technologies. There is growing interest in exploring its role in flexible electronics— particularly in wearable photodetectors and energy-harvesting devices. Its compatibility with polymer matrices and nanocomposites could enable the fabrication of stretchable or bendable systems, pushing the boundaries of current electronic designs. Likewise, the advent of additive manufacturing has opened up possibilities for incorporating BiVO₄ into 3D-printed functional materials. Imagine water-purifying structures or photoactive architectural components being printed on demand—these ideas, while speculative now, rest on an increasingly solid scientific foundation. Looking ahead, future studies should prioritize multifunctionality—leveraging BiVO₄’s photocatalytic, electronic, and structural attributes in tandem rather than isolation.

Multifunctional applications not only maximize material utility but also reduce component redundancy in complex systems. Additionally, establishing collaborative frameworks between material scientists, chemical engineers, and industrial designers will be essential to bridge the knowledge and application divide. As the field matures, such cross-disciplinary efforts will likely become the linchpin for realizing the full technological promise of BiVO₄ nanoparticles.

Bismuth Vanadate nanoparticles represent a compelling class of materials with significant potential across various engineering domains, particularly in photocatalysis and energy conversion. The body of research to date underscores their unique structural and electronic characteristics, yet it also highlights ongoing challenges-especially in the realms of synthesis optimization, scalability, and system integration. The transition from promising lab-scale results to viable industrial applications will not occur in isolation. It demands a concerted, cross-disciplinary effort where chemists, engineers, and materials scientists align their innovations and methodologies. Moving forward, the success of BiVO₄ in real-world settings will depend not just on improving its intrinsic properties, but also on embedding it within thoughtfully designed, multifunctional systems. With sustained research and collaborative development, BiVO₄ nanoparticles could well be at the forefront of next-generation engineering materials— provided we engineer them with both precision and practicality in mind.

• Muhammad Jamil: Conceptualization, supervision, and final approval of the manuscript.
• Ajmal Shah: Research design oversight, critical revisions, and overall study guidance.
• Ghazal Aman: Conducted literature survey and prepared the initial manuscript draft.
• Faiza Shabir: Conducted literature survey and prepared the initial manuscript draft.
• Rainzaz: Conducted synthesis procedures and structural characterization analyses.
• Saima Rafiq: Conducted synthesis procedures and structural characterization analyses.
• Nasir Iqbal: Supported data interpretation and critical manuscript revisions.
• Nadia Aman: Supported data interpretation and critical manuscript revisions.
• Nabeela Aman: Drafted sections related to emerging engineering applications.
• Zainab Liaqat: Performed data collection and assisted in manuscript revision.
• Seeqal Aleena: Manuscript editing, formatting, and final proofreading.

The authors would like to acknowledge the support and cooperation received from colleagues and institutional resources during the preparation of this manuscript. No financial support was provided by any external agency or organization.

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