Carrier Pairs Research Articles

Lattice Distortion Creates Enhancements in Photocatalytic and Electrocapacitive Performance of Sol–Gel‐Derived Cu‐Doped NiTiO3

A remarkable 35% enhancement in the photocatalytic and electrocatalytic abilities of an ilmenite nickel titanate (NiTiO3) material is reported. This boost in catalytic performance is achieved by simply creating a static distortion in the rhombohedral unit cell by replacing a small proportion of a small‐size nondegenerate Ni (69 pm) with a large‐size degenerate Cu (73 pm). The materials are synthesized by using a simple sol–gel method. The appropriate doping amount of Cu facilitates the better separation of intrinsic charge carrier pairs by inhibiting their recombination. The photocatalytic and electrochemical activities of durable materials in aqueous MB dye (10 ppm) and KOH (1 molar) electrolyte solutions are found to be directly associated with this improvement in inherent charge carrier transfer characteristics. The enhanced photodissociation of MB dye (42–56%) and specific capacitance (381–450 F g−1) in a KOH (1 molar) electrolyte are in full accord with the investigations carried out using crystallographic and optoelectronic analysis, charging–discharging measurements, and electrochemical impedance (EIS) spectroscopy investigations. Same material with high textural surface areas or controllable particle morphologies might show a far better photo/electrocatalytic performance in a variety of practical applications.

Boosted Electrochemical Activity with SnO2 Nanostructures Anchored on α-Fe2O3 for Improved Charge Transfer and Current Density

This study presents a straightforward and cost-effective method to enhance the photoelectrochemical (PEC) water-splitting performance of α-Fe2O3 (F), SnO2 (S), and α-Fe2O3 decorated with SnO2 quantum dots (FS) photoanodes in a NaOH electrolyte. The FS electrode demonstrated a notable improvement in PEC efficiency within the electrolyte. In particular, the generated charges of the FS anode in the NaOH electrolyte reached approximately 12.01 mA cm−2 under illumination, indicating that the developed heterostructures effectively enhanced kinetics, leading to improved separation of induced carrier pairs. This active carrier-pair separation mechanism contributed considerably to the increased PEC activity in the 0.1 M NaOH electrolyte. The reduction in the bandgap of FS increased its absorption capability in visible light, which further enhanced the current density. Furthermore, the reduction in electrolyte resistance (9.71 Ω), internal resistance (20.19 Ω), charge transfer resistance (3.21 kΩ), Tafel slope (45.5 mV dec-1), limiting current density (−2.09 mA cm−2), and exchange current density (−3.68 mA cm−2) under illumination at the interface enhanced the charge density of FS. Further, a strong interaction among photoanode nanostructures significantly enhances PEC activity by improving efficient charge separation and transport, reducing recombination rates, and enabling quicker movement of charge carriers to the electrode/electrolyte interface. Thus, this study provides an effective approach to increasing the PEC activity of heterostructures.

Lattice Symmetry-Guided Charge Transport in 2D Supramolecular Polymers Promotes Triplet Formation.

Singlet-to-triplet intersystem crossing (ISC) in organic molecules is intimately connected with their geometries: by modifying the molecular shape, symmetry selection rules pertaining to spin-orbit coupling can be partially relieved, leading to extra matrix elements for increased ISC. As an analog to this molecular design concept, the study finds that the lattice symmetry of supramolecular polymers also defines their triplet formation efficiencies. A supramolecular polymer self-assembled from weakly interacting molecules is considered. Its 2D oblique unit cell effectively renders it as a coplanar array of 1D molecular columns weakly bound to each other. Using momentum-resolved photoluminescence imaging in combination with Monte Carlo simulations, the study found that photogenerated charge carriers in the supramolecular polymer predominantly recombine as spin-uncorrelated carrier pairs through inter-column charge transfer states. This lattice-defined recombination pathway leads to a substantial triplet formation efficiency (≈60%) in the supramolecular polymer. These findings suggest that lattice symmetry of micro-/macroscopic structures relying on intermolecular interactions can be strategized for controlled triplet formation.

The match of the thickness of g-C3N4 nanotubes and migration of photogenerated carrier under external magnetic field

As a new method to obtain green and renewable energy, photocatalysis, converting from sunlight to chemical energy on the catalysts, shows its superiority since being experimentally found due to easy access and cleanliness. Graphite carbon nitride (g-C3N4), as an efficient photocatalyst with a band gap respond to visible light, is prepared in nanotube morphology by template method to provide convenience for the directional transfer of light and separation of carriers to improve photocatalytic activity and quantum efficiency. The thicknesses of g-C3N4 nanotubes (NTs) were controlled by addition amount of the precursor mass in the annealing treatment process. The migration of photogenerated electrons and holes in the wall of g-C3N4 NTs was accelerated in reverse to bypass recombination center in an external magnetic field to improve the photocatalytic activity. The critical thickness of g-C3N4 NTs wall is 72 nm for separating and impelling the photogenerated carrier pairs to the surface in the greatest extent possible and was proved by the experimental results of photoelectrochemical tests and photoluminescence spectra.

2D/1D nested hollow porous ZnIn2S4/g-C3N4 heterojunction based on morphology modulation for photocatalytic CO2 reduction

The two-dimensional (2D) composite one-dimensional (1D) heterojunction structure is one of the main strategies for constructing composite photocatalysts for photocatalytic reduction of carbon dioxide (CO2). However, morphology modulation for 2D/1D heterojunction is an important way to enhance performance. In this study, a unique 2D/1D ZnIn2S4/g-C3N4 nested hollow porous heterojunction structure was constructed by an in-situ growth method with spatial confinement effect. The synergy between 1D g-C3N4 and 2D ZnIn2S4, achieved through advanced morphology modulation at an optimal ratio of 3:1, results in the formation of the CZ-3 photocatalyst. This unique configuration enables a simultaneous high yield of carbon monoxide (CO) and methane (CH4), achieving 79.96 μmol/g and 17.33 μmol/g respectively, under visible light irradiation without the need for sacrificial agents. The core of this enhanced photocatalytic performance is attributed to the employment of a type-II heterojunction mechanism, which optimizes the transfer of photogenerated carriers. Ultraviolet-visible diffuse reflection spectrum, photoluminescence spectrum and photoelectrochemical analysis reveal the effect of morphology on photocatalytic performance in terms of visible light absorption, photogenerated carrier pairs separation and electronic band structure of heterojunction. By combining the advantages of 2D/1D structural benefits with the efficient charge dynamics of a type-II heterojunction, this work provides new ideas for improving the morphology of composite heterojunction photocatalysts with 2D/1D structure to enhance the photocatalytic CO2 reduction performance.

Modularization of Regional Electronic Structure over Defect-Rich CeO2 Rods for Enhancing Photogenerated Charge Transfer and CO2 Activation.

Oxygen vacancy (OV) engineering has been widely applied in different types of metal oxide-based photocatalytic reactions. Our study has shown that the redistributed OVs resulting from voids in CeO2 rods lead to significant differences in the band structure in space. The flat energy band within the highly crystallized bulk region hinders the recombination of photogenerated carrier pairs during the transfer process. The downward curved energy band in the surface region enhances the activation of the absorbents. Therefore, the localization of the band structure through crystal structure regionalization renders V-CeO2 capable of achieving efficient utilization of photogenerated carriers. Practically, the V-CeO2 rod shows a remarkable turnover number of 190.58 μmol g-1 h-1 in CO2 photoreduction, which is ∼9.4 times higher than that of D-CeO2 (20.46 μmol g-1 h-1). The designed modularization structure in our work is expected to provide important inspiration and guidance in coordinating the kinetic behavior of carriers in OV defect-rich photocatalysts.

Nanohybrid of two-dimensional tellurium and metal sulfotelluride for solar-driven photocatalytic hydrogen production from seawater

The use of sunlight radiation to cause the dissociation of seawater has tremendous promise as a green method for hydrogen production. Herein, tellurides and sulfotellurides of cadmium and zinc and solid solutions like CdxZn(1−x)SyTe(1−y) were synthesized by a coprecipitation method at room temperature. The prepared materials were tested as photocatalysts to produce H2 from seawater using lactic acid as a sacrificial reagent assisted by a solar simulator. All photocatalysts were active for hydrogen production from seawater and artificial sunlight. The cadmium-free photocatalyst (ZnSTe) was the most active one with a hydrogen production rate of 378.85 µmol g−1 h−1, followed by CdZnSTe (374.7 µmol g−1 h−1). The low sulfur content profoundly changes the UV–vis absorption spectra of the sulfotellurides, improving photocatalytic activity. XPS and TEM analysis revealed that the ZnSTe is composed of elemental tellurium nanosheets decorated with nano amorphous ZnTe and cubic phase ZnO. Thus, the p-n heterojunction formation between the ZnTe and ZnO improves the separation and migration rates of photogenerated carrier pairs, improving the solar-driven H2 production. Furthermore, the presence of 2D Te nanosheets dispersed in ZnSTe may contribute as support for charge transfer, which is essential in increasing photocatalytic activity.

Dichotomy of heavy and light pairs of holes in the t−J model

A key step in unraveling the mysteries of materials exhibiting unconventional superconductivity is to understand the underlying pairing mechanism. While it is widely agreed upon that the pairing glue in many of these systems originates from antiferromagnetic spin correlations, a microscopic description of pairs of charge carriers remains lacking. Here we use state-of-the art numerical methods to probe the internal structure and dynamical properties of pairs of charge carriers in quantum antiferromagnets in four-legged cylinders. Exploiting the full momentum resolution in our simulations, we are able to distinguish two qualitatively different types of bound states: a highly mobile, meta-stable pair, which has a dispersion proportional to the hole hopping t, and a heavy pair, which can only move due to spin exchange processes and turns into a flat band in the Ising limit of the model. Understanding the pairing mechanism can on the one hand pave the way to boosting binding energies in related models, and on the other hand enable insights into the intricate competition of various phases of matter in strongly correlated electron systems.

Synergistic Optimization of Morphology and Vacancies on Diatomic Rhodium Catalysts Dispersed on Carbon Nitride for Efficient Photocatalytic Reduction of CO2

AbstractDiatomic site catalysts (DAC) have better performance with higher metal content and more flexible active sites compared with single atomic site catalysts (SAC). Herein, the authors for the first time achieved Rh2 DAC on loose porous g‐C3N4 hollow nanospheres with N‐vacancies and applied to photocatalytic CO2 reduction reaction, overcoming the current limitations of the low electron–hole recombination rate and prolong the lifetime of the photogenerated carrier. The high specific surface area of hollow nanosphere facilitates the uniform dispersion and anchoring of Rh2 diatomic pairs, while the N‐vacancies induce a stable 3N/Rh‐Rh/1N2C coordination between the carrier and Rh2 diatomic pairs. The local charges on the support framework with N vacancies tend to be transferred to Rh2 diatomic site by 3N/Rh‐Rh/1N2C bridge, which made the charge enriched Rh2 diatomic site become the active center of reaction, enhance charge separation efficiency of Rh2/HCNS‐Nv. Compared with Rh1 SAC, further Density Functional Theory (DFT) calculation confirms that Rh2 DAC can effectively stabilize rate‐limiting intermediates CHO*, and well weaken the C─O bond strength in CH3O* species, promote the generation and separation of CH4, resulting in high CO2 reduction efficiency and CH4 electron selectivity of up to 91.65%.

Enhanced photocatalytic degradation of tetracycline by improving electron flux at the Schottky junction between Bi nanoparticles and MoS2-anchored RGO

In this work, a heterostructured metallic Bi/MoS2 photocatalyst (MBix) was prepared via uniform decoration of plasmonic bismuth nanoparticles onto the surface of MoS2 nanosheets. MBix catalysts were then loaded onto the surface of reduced graphene oxide (RGO) using a simple hydrothermal method to form RGO/MBix nanocomposite. RGO/MBix heterostructures demonstrated significantly improved photocatalytic performance for the removal of tetracycline (TC) under visible-light irradiation. The enhanced photocatalytic activity was found to be dependent on the level of Bi and RGO in the catalyst. The degradation rate over the optimum catalyst (RGO-2.5/MBi1.0) was six-fold higher than that of pristine MoS2. The enhanced photocatalytic activity was due to the improved light-harvesting and promoted separation efficiency of carrier pairs through the local surface plasmonic resonance (LSPR) effect of Bi nanoparticles and thus effective electron migration in Bi/MoS2 hetero-interface. Moreover, reduced graphene oxide (RGO) as a supreme electron sink provided a conduction path for excited electrons, and further decreased the rate of electron-hole recombination. The reduced charge recombination was well supported by photoluminescence and electrochemical impedance analyses. The radical trapping experiments indicated that the hydroxyl and superoxide radicals were the main active species to initiate TC degradation. Developing earth-abundant Bi-based photocatalysts, as well as the facile and economical approach to fabricating LSPR-enhanced composite will provide new insights into replacing the noble metals materials for environmental remediation.

Self-sacrificed BiOBr template-assisted synthesis of α-Bi2O3/Bi3O4Br heterojunctions with oxygen vacancies for enhanced photocatalytic nitrogen fixation

The catalytic conversion of nitrogen to ammonia is one of the most significant processes in nature and the chemical industry. However, the traditional Haber-Bosch process of ammonia synthesis consumes substantial energy and emits a large amount of carbon dioxide. The efficiency of photocatalytic N2 activation is severely limited by the lack of N2 adsorption sites and poor carrier utilization. Herein, an efficient α-Bi2O3/Bi3O4Br heterojunction is proposed with a photocatalytic nitrogen fixation activity of 238.67 μmol·g−1·h−1. Compared with the BiOBr precursor, α-Bi2O3 and Bi3O4Br, the α-Bi2O3/Bi3O4Br heterojunction with oxygen vacancies can improve the adsorption and activation capacity of N2 and promote the separation efficiency of charge carrier pairs by accommodating photogenerated electrons under visible light through the mechanism of N-type semiconductors. Therefore, oxygen vacancies and heterojunction engineering of semiconductive nanomaterials provide a promising method for the rational design of photocatalysts to enhance the rate of ammonia synthesis under mild conditions.

CuInS2 quantum-dot-modified g-C3N4 S-scheme heterojunction photocatalyst for hydrogen production and tetracycline degradation

CuInS2 quantum-dot (CIS QD)-modified g-C3N4 (CN) catalysts (CIS/CN) were prepared with the aid of an in-situ growth process. The as-obtained photocatalysts were explored by measuring their crystallinity, surface morphology, binding energy and light absorption activity. The photocatalytic efficiency of the photocatalysts was evaluated through photocatalytic water splitting for hydrogen production and tetracycline (TC) antibiotic degradation under the simulated solar light and visible light respectively. The optimized sample (10CIS/CN) showed the best photocatalytic activity: producing 102.4 µmol g−1 h−1 of hydrogen in 1 h, or degrading 52.16% of TC in 120 min, which were respectively 48 or 3.4 times higher than the photocatalytic activity of CN itself. The enhancement in the efficiency of the composite system was principally accredited to the enlargement of light absorption, the more effective in charge transfer and the dropping of the charge carrier pair recombination through a formed S-scheme heterojunctional interface. This work is an effort to adjust CN-based polysulfide QD for speedy photocatalysis. The enriched photocatalytic activity grants a new sense for adjusting the optical properties of CN.

Modulation and demodulation with quadrature square waves as carriers to improve spectrum utilization

Frequency division modulation enables fast and highly accurate detection of multiple signals, but its spectrum utilization is extremely low. Of course, existing methods improve the spectrum utilization by using quadrature signals as carriers, but it requires the carrier generation to be synchronized with the start of the acquisition. This is difficult to achieve when the carrier generation and the signal acquisition are not controlled by the same clock. Therefore, this paper proposes a demodulation method for the case where the carrier signal is a pair of quadrature square wave signals and the start of the carrier is not synchronized with the sampling. The method demodulates two signals modulating a pair of quadrature carriers by calculating the phase of one independent carrier signal. In this paper, three-wavelength multispectral images are acquired, and the demodulation results are compared with those acquired by the time-division method. The results show that there is a high similarity between the two, which proves the effectiveness of the method proposed in this paper, improves spectrum utilization, and is useful for the acquisition of multiplexed signals.

Design and synthesis of Bi-doped NiAl-LDH/g-C3N4 heterostructure; a novel 2D/2D system for simultaneous enhanced photocatalytic degradation and fluorescence sensing of ciprofloxacin

2D systems enable new opportunities for the development of photocatalysts. Layered double hydroxides (LDHs) indicate a wide range of applications due to their tunable functional properties. Regarding the intrinsic catalytic performance and excellent electronic structure of LDHs, and physicochemical stability of g-C3N4, we innovatively propose and investigate a novel Bi-doped NiAl-LDH/g-C3N4 2D/2D heterostructure system toward visible-light-driven photocatalytic degradation and fluorescence sensing of ciprofloxacin (Cipro). Based on the electrostatic self-assembly method, LDH nanosheets were grown on the g-C3N4 surface. SEM and TEM images confirmed that the LDH nanosheets were successfully loaded on the carbon nitride’s smooth surface. The most efficient composite (40%-g-C3N4/LDH) displayed 86% Cipro removal efficiency over 180 min under visible light irradiation. The main reason for the aforementioned improvement in catalytic activity was due to the intimate face-to-face contact in heterojunction between two semiconductors and increased flow of charge-carrier to the surface. As an auxiliary agent, bismuth-containing LDH can trap electrons and thus reduce carrier pairs recombination. Additionally, the prepared composite displayed excellent fluorescence sensitivity toward Cipro with a low detection limit of 3.7 nM. Our approach will provide a new perspective on designing 2D/2D heterojunctions between LDH and other two-dimensional semiconductors toward simultaneous photodegradation and detection of antibiotics.

1D S-scheme heterojunction of urchin-like SiC-W18O49 for enhancing photocatalytic CO2 reduction

Constructing heterojunction is an important method to improve the performance of photocatalyst for CO2 reduction. In this work, W18O49 nanosheets (NSs) were grown on the surface of SiC nanocages (NCs) to form the sea urchin ball morphology by solvothermal method. The SiC-W18O49 composite photocatalyst processes 1D S-scheme heterojunction electron transport pathway. The special urchin morphology provides a large surface area for the contact between photocatalyst and CO2 reactants. Meantime, the S-scheme internal electric field at the heterogeneous interface of SiC-W18O49 composite photocatalyst can effectively promote the separation and migration of photogenerated carrier pairs owing to 1D heterojunction structure. The photocatalytic CO2 reduction products (CO + CH4 + CH3OH) can be produced up to 21.87 μmol g−1 h−1 by SiC-W18O49 composite photocatalyst, which was 3.38 and 3.71 times of the total reduction activity of the parent SiC and W18O49, respectively. This work will provide a new idea for the design of heterojunction morphology and structure for boosting photocatalytic CO2 reduction.

Core-shell structure strategy and oxygen vacancy engineering of 0.1LaMnO3@0.9(Ba0.5Sr0.5)TiO3 ceramics towards tuning electrical properties

In recent years, core-shell structures have attracted much attention for their potential in tuning the functional properties of materials and have become an effective method for preparing high-performance materials. In this work, core-shell structured 0.1LaMnO3@0.9(Ba0.5Sr0.5)TiO3 nanoparticles were fabricated by sol-gel method and dense ceramics were prepared at different sintering temperatures. The phase composition, morphology, chemical state and electrical properties were systematically investigated. Structural analysis confirmed the formation of 0.1LaMnO3@0.9(Ba0.5Sr0.5)TiO3 core-shell nanostructures. The results show that the prepared samples exhibit typical negative temperature coefficient characteristics in the range of 50–1000 °C, which is derived from the effect of carrier pairs and oxygen vacancies on the electrical properties. This study provides new insights from structure to material into guiding the development and design of advanced thermistor materials for temperature sensing applications.

Tuning of electrical properties of xBi(Zn0.5Ti0.5)O3-(1-x) (Ba0.5Sr0.5)TiO3 ceramics by composition design and bandgap engineering

Herein, the xBi(Zn0.5Ti0.5)O3-(1-x) (Ba0.5Sr0.5)TiO3 (x = 0.05, 0.10, 0.15, 0.20) novel negative temperature coefficient (NTC) ceramic materials were fabricated by solid-state method. X-ray diffraction revealed that xBi(Zn0·5Ti0.5)O3-(1-x) (Ba0.5Sr0.5)TiO3 successfully formed solid solution. The UV–vis diffuse spectra of the samples indicate that the band gap increases with the increasing Bi(Zn0·5Ti0.5)O3 content. The resistance temperature curve showed that with the increase of Bi(Zn0·5Ti0.5)O3 content, the resistivity ρ of the ceramics at 400 °C increased from 5.96 × 106 to 2.67 × 107 Ω cm, as well as an increase in the B400/800 from 12374.6 to 13469.1 K. The enhanced resistivity is attributed to the increased band gap and reduced carrier pairs caused by the Bi(Zn0.5Ti0.5)O3 modification. The impedance data indicates that the conduction process is activated by thermal. The ceramic samples exhibit the excellent NTC characteristics over a range of 400 °C–1000 °C. Hence, the xBi(Zn0.5Ti0.5)O3-(1-x) (Ba0.5Sr0.5)TiO3 ceramics have the potential to become high temperature NTC ceramics that can operate in a wide temperature range.

Solution‐Processed and Room‐Temperature Spin Light‐Emitting Diode Based on Quantum Dots/Chiral Metal‐Organic Framework Heterostructure

AbstractSpin optoelectronics is an indispensable key for the future development of spintronics. In conventional spin light emitting diodes (LEDs), spin‐polarized carrier pairs are injected electrically into the light emitting layer and create circularly polarized light (CPL). Generally, spin‐polarized carriers are accomplished using ferromagnetic contacts or applying an external magnetic field, which will produce several drawbacks, including low temperature operation, low spin‐polarized carriers injection efficiency, etc. To circumvent the existing shortcomings, here, an alternative approach is proposed and achieves spin‐polarized LEDs at room temperature based on quantum dots (QDs)/chiral metal‐organic framework heterojunction without using ferromagnetic contacts or magnetic fields. The spin‐polarized injected layer composed of self‐assembled monolayer (SAM)/Chiral‐MOF ([Sr(9,10‐adc)(DMAc)2]n)) film, which produces spin‐polarized holes with spin orientation, determining the polarization and strength of circularly polarized electroluminescence (CP‐EL). The spin‐QLED emits CP‐EL at a rate of 12.24% efficiency, which provides an excellent alternative to generate new functionality for conventional QLEDs. The approach is anticipated to be very useful, enabling to offer a general methodology for generating not yet realized spin optoelectronic devices.

Tuning Catalytic Performance of C2N/GaN Heterostructure for Hydrogen Evolution Reaction by Doping

AbstractIn this work, a systematic theoretical study of the hydrogen evolution reaction (HER) catalytic activity of C2N/GaN heterostructure is carried out based on first principles. An indirect bandgap of 1.99 eV and type‐II band alignment are formed in the C2N/GaN heterostructure, which can facilitate the spatially efficient separation of photogenerated carrier pairs, and the band edge position matches the reduction potential of water. The catalytic performance of the HER reaction at the C and N sites is compared and that the N site is better in performance is found, but still requires a potential barrier of 0.60 eV. In order to improve the catalytic performance of the C2N/GaN heterostructure, an N atom is replaced by a P atom to obtain P‐C2N/GaN. The band alignment of the P‐C2N/GaN heterostructure is still type‐II, and the band edges satisfy the reduction potential of water. Fortunately, the P or N sites play a crucial role in the HER process with a relatively low overpotential of 0.38 eV, which suggests that P‐C2N/GaN can improve the catalytic performance of the heterojunction. Overall, the P‐C2N/GaN heterostructure has suitable band gap values and band edges, and efficient charge separation in the heterostructure makes it a promising HER catalyst.

Boosted natural sunlight driven photodegradation of organic dyes using rGO anchored Pr/Cu dual-doped ZnO nanocomposite: Characterization and mechanistic insight

The advancement of sunlight-driven metal oxide semiconductor-based, highly efficient photocatalysts for removing contaminants like dyes from wastewater remained a challenge. In this work, Pr/Cu dual-doped ZnO anchored with different rGO concentrations were synthesized by simple co-precipitation and ultrasonication route. The structural, morphological, and optical characterization of prepared materials was performed with different techniques and employed for degrading diverse kinds of dyes pollutants under natural sunlight illumination. The photodegradation efficiency after 40 min sunlight illumination towards Methyl Orange (MO) was 51.00, 75.00, and 99.76% for ZnPrCuO (S1), ZnPrCuO/rGO (1:1) (S2), and ZnPrCuO/rGO (1:2) (S3), respectively. The results suggested that the introduction of Pr/Cu and rGO significantly boosted the photodegradation ability of ZnO under sunlight. Especially, S3 nanocomposite exhibited the highest photodegradation of safranin-O (SO), Rhodamine-B (RhB), and methylene blue (MB) dyes, having degradation efficiency of 65.50, 91.40, and 99.80%, respectively, in 40 min. The scavenger test results exhibited that •OH and •O2− were the foremost active species in the photodegradation process. Moreover, the reusability experiments and tracing XRD after reusing samples revealed that the S1 catalyst has excellent recyclability (6th cycle). The reduction in energy bandgap and creation of impurity energy level by Pr/Cu doping leads to inhibit carrier pair recombination and effective charge transfer/separation. These findings revealed that Pr/Cu doping and rGO have the potential to enhance the visible light response of ZnO to eliminate dyes pollutants in wastewater with energy saving.