BiVO4 Photocatalyst Research Articles

Accelerating Small Electron Polaron Dissociation and Hole Transfer at Solid-Liquid Interface for Enhanced Heterogeneous Photoreaction.

In a photocatalysis process, quick charge recombination induced by small electron polarons in a photocatalyst and sluggish kinetics of hole transfer at the solid-liquid interface have greatly limited photocatalytic efficiency. Herein, we demonstrate hydrated transition metal ions as mediators that can simultaneously accelerate small electron polaron dissociation (via metal ion reduction) and hole transfer (through high-valence metal production) at the solid-liquid interface for improved photocatalytic pollutant degradation. Fe3+, by virtue of its excellent redox ability as a homogeneous mediator, enables the BiVO4 photocatalyst to achieve drastically increased photocatalytic degradation performance, up to 684 times that without Fe3+. The enhanced performance results from Fe(IV) species production (via Fe3+ oxidation) induced by dissociation of small electron polarons (via Fe3+ reduction), featuring an extremely low kinetic barrier (5.4 kJ mol-1) for oxygen atom transfer thanks to the donor-acceptor orbital interaction between Fe(IV) and organic pollutants. This work constructs a high-efficiency artificial photosynthetic system through synergistically eliminating electron localization and breaking hole transfer limitation at the solid-liquid interface for constructing high-efficiency artificial photosynthetic systems.

An investigation of Z-scheme homojunction BiVO4 photocatalysts for efficient green removal of ammonia nitrogen

With in-depth research on photocatalytic pollution removal, homojunction semiconductors stand out for their simple structure and stability. However, their similar energy levels result in lower photocatalytic activity compared to heterojunctions, limiting their applications in photocatalysis. Therefore, in this study, homojunction BiVO4 photocatalysts with staggered energy level structures were prepared by compositing crystalline facet-modified BiVO4 with oxygen vacancy-modified BiVO4 and used for the removal of ammonia nitrogen from water. The homojunction BiVO4 photocatalysts were successfully prepared, and the good photocatalytic performance of OBVV-2 was confirmed by several characterizations and tests, with the ammonia nitrogen removal rate of 84.3 % under visible light, of which 93.6 % was converted into harmless N2. The Z-scheme transfer mechanism was illustrated by radical capture experiments, and the repeated cycling experiments demonstrated that the homojunction photocatalysts have excellent stability. In conclusion, this study confirmed that the Z-scheme homojunction BiVO4 (OBVV-2) photocatalyst has good potential for application and provides a homojunction solution for efficient and green ammonia nitrogen removal.

Facet-Engineered BiVO4 Photocatalysts for Water Oxidation: Lifetime Gain Versus Energetic Loss.

A limiting factor to the efficiency of water Oxygen Evolution Reaction (OER) in metal oxide nanoparticle photocatalysts is the rapid recombination of holes and electrons. Facet-engineering can effectively improve charge separation and, consequently, OER efficiency. However, the kinetics behind this improvement remain poorly understood. This study utilizes photoinduced absorption spectroscopy to investigate the charge yield and kinetics in facet-engineered BiVO4 (F-BiVO4) compared to a non-faceted sample (NF-BiVO4) under operando conditions. A significant influence of preillumination on hole accumulation is observed, linked to the saturation and, thus, passivation of deep and inactive hole traps on the BiVO4 surface. In DI-water, F-BiVO4 shows a 10-fold increase in charge accumulation (∼5 mΔOD) compared to NF-BiVO4 (∼0.5 mΔOD), indicating improved charge separation and stabilization. With the addition of Fe(NO3)3, an efficient electron acceptor, F-BiVO4 demonstrates a 30-fold increase in the accumulation of long-lived holes (∼45 mΔOD), compared to NF-BiVO4 (∼1.5 mΔOD) and an increased half-time, from 2 to 10 s. Based on a simple kinetic model, this increase in hole accumulation suggests that facet-engineering causes at least a 50-100 meV increase in band bending in BiVO4 particles, thereby stabilizing surface holes. This energetic stabilization/loss results in a retardation of OER relative to NF-BiVO4. This slower catalysis is, however, offset by the observed increase in density and lifetime of photoaccumulated holes. Overall, this work quantifies how surface faceting can impact the kinetics of long-lived charge accumulation on metal oxide photocatalysts, highlighting the trade-off between lifetime gain and energetic loss critical to optimizing photocatalytic efficiency.

Development of a novel lightweight brick-activated carbon based BiVO4 photocatalyst and its adsorption-photocatalytic behavior for toxic dye removal in wastewater

The purpose of this research was to develop a novel photocatalyst by loading BiVO4 (BVO) particles on lightweight brick-activated carbon (LWB-AC). The characterizations of as-prepare samples were studied using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–VIS –NIR spectrophotometer (UV-VIS-NIR) techniques. The adsorption-photocatalytic methylene blue (MB) removal, methyl orange (MO) removal and rhodamine B (RhB) removal of the as-prepared LWB-AC based BVO photocatalyst were tested by irradiating visible light. The results showed that the LWB-AC based BVO photocatalyst exhibited the highest adsorption-photocatalytic efficiency for the removal of MB, MO and RhB dyes under visible light irradiation as compared to the other samples. This might be due to the synergistic effect between AC and BVO on the surface of LWB. Moreover, the presence of both AC and BVO on the surface of LWB helped in preventing the electron-hole recombination, resulting in the enhanced adsorption-photocatalytic activity. For reusability tests, the LWB-AC based BVO photocatalyst did not show the loss of adsorption-photodegradation ability of MB, MO and RhB dyes after five runs. A probable adsorption-photodegradation mechanism of LWB-AC based BVO photocatalyst was also proposed.

Controllable synthesis of BiVO4 photocatalysts with distinct morphology toward different dyes degradation in the presence of peroxydisulfate

Controllable synthesis of BiVO4 photocatalysts with distinct morphology toward different dyes degradation in the presence of peroxydisulfate

Sustainable carbonaceous material from durian peel to modify the photocatalytic activity of Ag/activated carbon/BiVO4 for RhB degradation under visible light irradiation

High performance and sustainable Ag/activated carbon (AC)/BiVO4 photocatalyst was synthesized via hydrothermal method, followed by photodeposition of Ag. The AC was derived from organic waste of Monthong durian peels which was recycled to achieve carbon neutrality and encourage sustainable friendly environment. The AC modified band energy and promoted reducing power of the obtained photocatalyst with increasing of oxygen vacancies for electron trapping on the photocatalyst surface, thus enhancing photoexcited charge separation and producing more active species as evidenced by PL, EIS, and scavenger experiment. With the modification of Ag, the photoexcited electrons are efficiently trapped that the available h+ are mobilized through the oxygen vacancies occurring by modified high electron density of AC and Ag thus enhanced photocatalytic performance as exhibited by XPS. The band energy alignment of the developed Ag/AC/BiVO4 is proposed with the improved photocatalytic RhB degradation.

Role of oxygen vacancy enriched m-BiVO4/t-BiVO4 isotype heterojunction for enhanced photocatalytic degradation of rhodamine B dye and in ferroelastic to paraelastic phase transition

Mixed-phase isotype heterojunction oxide materials with superior photocatalytic activities have recently revealed a significant coupling between individual phases with controlled optical properties. Therefore, we focus on synthesizing a mixed-phase monoclinic-tetragonal (m-t) BiVO4 photocatalyst using hydrothermal method. The increased recombination rate of electron-hole (e−-h+) pairs limits the photocatalytic performance of monoclinic (m) BiVO4 photocatalysts. Therefore, effective spatial charge carrier separation can be improved by creating an isotype heterojunction between the phases m-BiVO4 and t-BiVO4. The precursor pH, mechanical grinding, and calcination temperature regulate the formation of m-t BiVO4. The phase fractions of the two phases in m-t BiVO4 sample are 85% monoclinic and 15% tetragonal. Herein, we demonstrate the optical properties and photocatalytic activity based on the crystal chemistry of m-BiVO4 and m-t BiVO4. Temperature-dependent Raman measurements suggest a second order ferroelastic monoclinic to paraelastic tetragonal phase transition above 530 K owing to optical phonon anharmonic coupling interactions. The small increase (5 °C) in Tc in m-t BiVO4 compared to m-BiVO4 is due to the coexistence of tetragonal and monoclinic phases. The optical band gap of m-t BiVO4 is larger than that of m-BiVO4. Additionally, the evaluation of BiVO4 photocatalytic activity over rhodamine-B (Rh-B) dye suggests that the m-t BiVO4 with 97.5% degradation efficiency is superior compared to m-BiVO4 with 89% degradation efficiency. This is because, the two phases (m and t) of BiVO4 form an isotype heterojunction interface, which results in a high charge separation efficiency, as demonstrated by photocurrent studies and electrochemical impedance spectroscopy. Moreover, oxygen vacancies tune the charge carrier dynamics through the modification of band edges. These findings regarding the isotype phase-junction mechanism provide possibilities for innovative ideas for highly efficient mixed-phase isotype heterojunction photocatalysts for wastewater remediation.

Improving Photocatalytic, Antimicrobial Properties, and Enzymatic Activity via Ag Doping in BiVO4 Photocatalysts Using a Simple Co-precipitation Technique and Verified by Theoretical Analysis

Improving Photocatalytic, Antimicrobial Properties, and Enzymatic Activity via Ag Doping in BiVO4 Photocatalysts Using a Simple Co-precipitation Technique and Verified by Theoretical Analysis

BiVO4-Driven photocatalytic degradation of pharmaceutical in Slurry Bubble Column Reactor: Influencing factors and toxicological profiling

As the pursuit for sustainable and effective solutions to address environmental pollution intensifies, a comprehensive approach in photocatalysis has become a subject of increasing interest. In this study, BiVO4 photocatalyst synthesized through a pH-controlled hydrothermal method was used for the degradation of tetracycline (TET), a prevalent pharmaceutical pollutant. Optimal conditions, particularly a pH of 9 and enriched dissolved oxygen (DO), significantly improve TET removal, achieving a 96 % degradation efficiency with a rate constant of k = 0.1069 min−1. The investigation revealed that the degradation predominantly involves the generation of reactive oxygen species (ROS), notably O2•−, which play a crucial role in the degradation of TET. Using the “ecological structure–activity relationships” (ECOSAR) program, the toxicity of the intermediates was assessed, highlighting the environmental implications of the photocatalytic process. In addressing the scalability for industrial applications, a Slurry Bubble Column Reactor (SBCR) was employed, and separation-stability tests of the photocatalyst were conducted. These tests confirmed the photocatalyst’s long-term effectiveness and stability, underscoring its potential for repeated use in large-scale applications. This comprehensive research not only underscores the potential of BiVO4 in removing environmental contaminants but also provides vital insights into ecological safety.

Insights into the PMS activation towards phenol removal mechanism by a Ti3C2-MXene doped BiVO4 photocatalyst

In the field of water treatment, photocatalysis and the peroxomonosulfate (PMS) deep oxidation process have emerged as potential solutions for the degradation of refractory organic pollutants. In this study, a novel BiVO4/Ti3C2 composite photocatalytic material was successfully synthesized using a hydrothermal method. The energy band structure of this material was utilized to establish Schottky barriers, enhancing the separation of photogenerated carriers. This, in turn, facilitated the activation of PMS under visible light, generating reactive species that effectively degraded phenol. The results demonstrate that in the BT-3/PMS system, the degradation rate of phenol reached 87.2 % within 60 min, with a maximum degradation rate constant of 0.02537 min−1. This represents an 8.8-fold improvement compared to pure BiVO4 and a 5.2-fold improvement compared to pure PMS. Free radical tests indicated that SO4·- was the primary reactive species involved in the degradation process. This study offers a promising approach for the design of efficient and stable Schottky junction photocatalysts that can be activated by visible light and PMS to effectively degrade organic pollutants.

Intercalated Water Drives Anomalous Thermal Expansion in the Tetragonal Zircon Structured Bismuth Vanadate BiVO4 Photocatalyst.

The thermal transformation of the tetragonal-zircon (tz-) to tetragonal-scheelite (ts-)BiVO4 was studied by in situ synchrotron X-ray diffraction, thermogravimetric analysis, and Fourier-transformed infrared spectroscopy. Upon heating, the tetragonal zircon polymorph of BiVO4 (tz-BiVO4) transitioned to the ts-polymorph between 693-773 K. Above 773 K, single phase ts-BiVO4 was observed before transitioning to the monoclinic fergusonite (mf-) polymorph upon cooling. An anomaly in thermal expansion was observed between 400-500 K, associated with the loss of intercalated H2O/NH4 + from the coprecipitation procedure. Heating tz-BiVO4 resulted in contraction of the V-O bond distance and VO4 polyhedra volume, ascribed to rotation of the tetrahedra groups. Attempts to study this by neutron diffraction failed due to the large incoherent scatter from the hydrogenous species. Efforts to remove these species while maintaining the tz-BiVO4 structure were unsuccessful, suggesting they play a role in stabilizing the tz-polymorph. The local structure of both mf-BiVO4 and tz-BiVO4 were investigated by X-ray pair distribution function analysis, revealing local distortions.

Isotype BiVO4 heterostructure and the effect of photo-sono induced electron-hole pair

Owing to its suitable energy band and strong catalytic capacity, BiVO4 has received extensive attention in photocatalysis. Here, we suggest a straightforward approach to address the challenges of insufficient compatibility, poor charge transport characteristics, and limited surface adsorption properties commonly found in traditional BiVO4 photocatalysts. A heterojunction BiVO4 structure is developed by incorporating two distinct crystal phases within a single semiconducting material. A facile hydrothermal procedure is used to synthesize distinct crystalline phases of BiVO4 photocatalysts, viz., tetragonal, monoclinic, and monoclinic/tetragonal heterophase. The physicochemical characteristics of the pristine and isotype BiVO4 heterojunctions were characterized using various techniques. The photocatalytic activity of BiVO4 samples was examined by monitoring the degradation of rhodamine B (RhB). In order to boost the degradation reaction, ultrasonic sound waves are employed within the reaction medium. The present study examined the photocatalytic, sonocatalytic, and sonophotocatalytic activity of BiVO4 microcrystals in relation to the degradation of RhB dye. The results show that the crystalline phases of BiVO4 samples significantly influence the behaviour of photo-sono-induced charges. An interface in the monoclinic/tetragonal heterophase creates a spatial environment that facilitates charge transfer and enhances the separation of photo-sono-induced electron-hole pairs. The paper extensively examines the correlation between the behaviour of photo-sono-induced charge carriers and the level of sonophotocatalytic activity. This would provide greater insight into the intrinsic reasons for the enhancement in sonophotocatalytic activity.

Boosting the photocatalytic activity of bismuth vanadate (BiVO4) via optimization of the internal polarization

Photocatalytic performance can be improved by optimizing the morphology and surface texture of the photocatalyst or forming different p-n and/or n-n heterojunctions. Although the heterojunction system enhances photocatalytic property; however, an internal spontaneous polarization electric field may be much more effective due to the separation of electron-hole pairs when the polarization field forces them to move in different directions. The present study demonstrated this insight where the BiVO4 synthesis condition and polarization field forces were controlled via homogeneous precipitation in the presence of polyvinylpyrrolidone (PVP). The as-synthesized BiVO4 photocatalysts' structure and morphology were investigated using XRD, SEM, Raman, DRS, and PL. The result revealed that the increase of PVP concentration reformed the shaping to the truncated bipyramid-like shape and creates a spontaneous internal polarization that enhanced BiVO4 photocatalytic performance. The photocatalytic activity of BiVO4 was evaluated by monitoring the photocurrent enhancement using chronoamperometry, electrochemical impedance spectra and the photodegrading of methylene blue (MB) aqueous solution to harmless compounds in the presence of light. The spontaneous polarization between the different facets of BiVO4 crystal enhances the e−/h+ separation during internal facets homojunction and leads to four times photocurrent enhancement and the MB photocatalytic degradation rate increased from 0.43 to 1.92 min−1.

Photocatalytic Degradation of Crystal Violet on Cu, Zn Doped BiVO4 Particles.

Fabrication of codoped photocatalysts is a developing area of research. Herein, we explore the visible light photocatalytic properties of Cu, Zn codoped BiVO4 particles. Doping lower valent cations (Cu and Zn) makes the BiVO4 surface more acidic and enables us to target the basic crystal violet (CV) dye. The adopted hydrothermal protocol of synthesis results in the formation of Cu-Zn codoped monoclinic BiVO4 particles. Undoped monoclinic BiVO4, prepared by the same protocol, showed significant formation of oxygen vacancies. XPS analyses confirm the coexistence of Cu2+/Cu+ and Zn2+ dopants. Increased dopant percentage reduced oxygen vacancies. XRD indicates that Cu2+/Cu+ or Zn2+ dopants generally substitute Bi3+ in BiVO4. All photocatalysis activities for CV degradation are reported under near-neutral pH conditions. A typical codoped BiVO4 photocatalyst with 1% Zn and 2% Cu demonstrated the best CV degradation photocatalytic activity. The activity of this Zn, Cu codoped photocatalyst is better than that of pure, Zn-doped, and Cu-doped BiVO4 samples. Active species trapping experiments indicated the possible photocatalysis mechanism. The photocatalysts exhibited appropriate recyclability and photostability.

CTAC-assisted monoclinic BiVO4 with oxygen defects for efficient photocatalytic performances: A combined experimental and DFT study

Developing a photocatalyst with high photocatalytic efficiency, chemical stability, and self-degradation capability is essential for optimizing photodegradation processes in environmental applications. In this study, we synthesized a monoclinic BiVO4 photocatalyst whose surface morphology was modulated by hexadecyltrimethylammonium chloride (CTAC) using a facile hydrothermal method. Experimental results demonstrated a substantial increase in the degradation rate (99%) for the CTAC-modified monoclinic BV/CT25 photocatalyst (with an initial CTAC concentration of 25 g/L) compared to the CTAC-free tetragonal BiVO4 photocatalyst (73%). This highlights the effective enhancement of photocatalytic degradation performance through CTAC modification. Furthermore, density functional theory (DFT) calculations revealed that the band gap of BV/CT25 remained unchanged, suggesting that changes in oxygen vacancies (OVs) and density of states, along with the porous lattice structure, contributed to the improved performance. These findings were further supported by FESEM, as well as EPR and XPS characterizations. In addition, photodegradation tests at various pH conditions and cyclic tests suggested that the modification enhanced the morphological stability and reusability of the modified BiVO4 photocatalysts. Overall, this study provides valuable insights into the design of next-generation photocatalysts, leveraging surfactants to control surface properties and emphasizing the key attributes of high photocatalytic efficiency, chemical stability, and improved reusability.

Soft synthesis and analysis of structural parameters upon photoactivity of visible-active BiVO4-based ternary heterojunctions

Cu2O/Pt–BiVO4 and Cu2O/Au–BiVO4 photocatalysts are synthesized using a mild reducing agent (ascorbic acid) by an in-situ chemical reduction method at 25 °C. Pt and Au nanoparticles with an approximate size from 15 to 25 nm were incorporated onto BiVO4 powders. Crystalline phases are refined with the Rietveld method to evidence whether structural parameters contribute to enhance the photoactivity of the composites. The influences of structural defects and deposited metal are investigated to establish a relationship with their photoactivities. The as-synthesized BiVO4-based ternary photocatalysts displayed a strong optical absorption from UV to visible light shorter than 514 nm, with a blue-shift compared to that of pure BiVO4, resulting from the addition of the Au and Pt nanoparticles. The photocatalytic activities of the as-synthesized materials are evaluated under visible-light irradiation using the mineralization of 4-chlorophenol (4-CP) and dicloxacillin (DCX). The mineralization percentages achieved with Cu2O/Pt-BVO4 and Cu2O/Au–BiVO4 after 240 min of irradiation were 85% for 4-CP and 33% for DCX. It is assumed that those levels of TOC removal are due to the lowest content of oxygen vacancies in the photocatalysts, decreasing hole trapping, and subsequently hindering their recombination with the photoexcited electrons. Under this premise, structural defects (i.e. oxygen deficiency) present a more important effect on the photoactivity of the BiVO4-based materials than crystallite size, or other structural parameters. Moreover, the activity can also be ascribed to the Z-scheme Cu2O/BiVO4 heterojunction enhancing redox potentials of charge carriers, the incorporation of Pt and Au nanoparticles, enhancing charge separation either by trapping photo-generated electrons, generating the electron sink effect.

SYNTHESIS OF NICKEL-DOPED BIVO4 MATERIALS BY HYDROTHERMAL METHOD AND EVALUATE THE PHOTOCATALYTIC ABILITY TO DECOMPOSE METHYLENE BLUE UNDER VISIBLE LIGHT

Ni-doped BiVO4 photocatalysts were successfully synthesized by hydrothermal method. The catalytic samples were characterized by scanning electron microscopy (SEM), UV-vis diffuse reflection spectroscopy (DRS), photoluminescence spectroscopy (PL) and X-ray diffraction (XRD). Based on the results of PL spectrum analysis, the electron-hole recombination phenomenon is limited by the presence of the second metal Ni in the structure at Bi3+ positions. The catalyst materials at the Ni doping ratios all have the monoclinic-scheelite BiVO4 structure as shown by the XRD and Raman methods. The photocatalytic ability of methyl blue (MB) on the Ni/BiVO4 catalyst was studied under visible light irradiation in order to contribute to reducing the current environmental pollution problem. The removal efficiency of MB varies with the doping ratio of Ni/BiVO4, reaching the highest decomposition efficiency of 84.77% in the 5% mol Ni sample, which is 30% higher than that of the BiVO4 sample. The BiVO4 material modified with Ni gives a high photocatalytic efficiency of organic pigment decomposition under visible light indicates the potential improvement in the efficiency of a material for existing applications and exploit many new applications in the future.

Enhanced visible light photocatalytic performance of Er, Mn co-doped monoclinic BiVO4 for efficient organic pollutant degradation

Er/Mn co-doped BiVO4 was synthesized via a one-pot hydrothermal method. Co-doping results in smaller crystal size and wider absorption edge of visible light. Er6%Mn2%/BiVO4 exhibits higher degradation efficiency than pure and single-doped BiVO4.

The improvement of photocatalytic activity of BiVO4 modified with Co(OH)2 nanoflake arrays for photocatalytic and photo-electrocatalytic desulfurization

Various and economical pure BiVO4 and Co(OH)2 nanoflake deposited BiVO4 photocatalysts have been prepared using the electrodeposition technique. Improved photocurrent density of 64 µA/cm2 at 1.0 V vs. Ag/AgCl was shown by Co(OH)2-BiVO4-150 photoanode (BiVO4 after 150 s of cobalt electrodeposition), which is about 8 times higher compared with BiVO4 photoanode. The catalysts prepared have also been used in the photocatalytic oxidation of dibenzothiophene (DBT), which is applied to stimulate fluid catalytic cracking for gasoline production in n-heptane solution. The corresponding parameters in the optimization of oxidative desulfurization of DBT were reaction time, temperature, solvent, DBT concentration and electrical bias voltage. The highest DBT desulfurization efficiency was shown by Co(OH)2-BiVO4-150. Based on the mechanism of photocatalytic oxidation, the superoxide and hydroxyl radicals played major parts in DBT degradation. Co(OH)2-BiVO4-150 photoanode showed better photo-electrocatalytic degradation efficiency, reaching a high 78.3% DBT removal even during the reaction time, in comparison with photocatalysis and electrocatalysis. The photocatalytic degradation system containing Co(OH)2-BiVO4-150 may be recycled six times without any important reduction of photocatalytic activity. This procedure introduces a simple and sustainable approach for the modification of BiVO4 to improve its photoelectrochemical and photocatalytic activity.

E-beam irradiation-induced synthesis of hydroxyethyl cellulose/(Cu2O-rGO)/BiVO4-based nanocomposite for photocatalytic remediation of wastewater under visible light

Using E-beam irradiation as an eco-friendly technique for initiation and crosslinking, a series of Hydroxyethyl Cellulose-poly vinyl alcohol copolymer hydrogels were synthesized as templates for cuprous oxide (Cu2O), reduced graphene oxide (rGO) and bismuth vanadate (BiVO4) nanoparticles to be used as nanocomposites photocatalysts for methylene blue (MB) dye decolorization using visible light. Preparation conditions were optimized to ensure the construction of a good network architecture and therefore the highest gelation degree. For the preparation of (Cu2O@rGO)/BiVO4 nanocomposites, a series of rGO was decorated by Cu2O using the precipitation method, followed by mixing with BiVO4 which was synthesized hydrothermally. (EDX), (XRD), (TEM), and (SEM) were used for nanoparticle characterization. The thermal characteristics of the fabricated nanocomposites were evaluated using thermal gravimetric analysis. The presence of rGO enhanced the decolorization efficiency of MB about 20 % higher than that of (HEC-PVA)/Cu2O which achieves only (59 %) decolorization efficiency. After the addition of BiVO4 NPs, the decolorization efficiency increased to reach 90 % after 150 min at pH 11 using a 10 ppm MB solution. The developed (HEC-PVA)/(Cu2O@rGO)/BiVO4 photocatalyst exhibits efficient reusability for 5 cycles. Treated dyed water shows a germination index (GI) of 82 % suggesting its suitability for irrigation of playgrounds and gardens.