High-performance Photocatalysts Research Articles

Treatment of antibiotics in water by SO3H-modified Ti3C2 Mxene photocatalytic collaboration with g-C3N4

Due to inherent limitations such as high carrier recombination efficiency, limited active sites, and suboptimal utilization of visible light, graphite-like carbon nitride (g-C3N4) has constrained its widespread application in water treatment within photocatalytic systems. In addressing this issue, the present study employed acid etching and sonochemistry to fabricate a Ti3C2-SO3H/g-C3N4 (TiCSOHCN) composite photocatalyst for the removal of tetracycline hydrochloride (TC). The amalgamation of Ti3C2-SO3H (TiCSOH) with g-C3N4 engendered the establishment of a discernible Schottky barrier, facilitating an expedited electron transfer rate. Photocatalytic degradation experiments demonstrate that, compared to individual components, the TiCSOHCN composite photocatalyst exhibits significantly enhanced photocatalytic activity. The removal efficiency of TC reaches 75.42 % within 2 h, and even after five cycles of experimentation, the degradation efficiency remains close to 70 %, indicating excellent stability. The augmentation can be predominantly ascribed to the cooperative influence arising from the synergy between Ti3C2-SO3H and g-C3N4. The augmentation of visible light responsiveness in g-C3N4, achieved through its modification with TiCSOH, resulted in the mitigation of photoelectron-hole pair recombination, consequently leading to an amelioration in the photocatalytic efficacy of the TiCSOHCN composite catalyst. Intermediate species arising from the degradation of tetracycline were discerned utilizing LC-MS, and conjectures regarding plausible degradation pathways were postulated. Evaluations of the ecotoxicological impact of tetracycline and its intermediates indicated a progressive diminution in toxicity throughout the course of the photocatalytic degradation process. Furthermore, through free radical capture and EPR tests, it was confirmed that ·O2– and ·OH are the primary active species responsible for the photocatalytic degradation of TC, substantiating the proposed rational photocatalytic degradation mechanism. This research provides an innovative approach to developing high-performance and stable photocatalysts.

Interfacial Electronic States of GeC/g-C3N4 van der Waal Heterostructure with Promising Photocatalytic Activity via Hydrogenation.

The bandgap of most known two-dimensional materials can be tuned by hydrogenation, although certain 2D materials lack a sufficient wide bandgap. Currently, it would be perfect to design non-toxic, low-cost, and high-performance photocatalysts for photocatalytic water splitting via hydrogenation. We systematically examine the impact of hydrogenation on the optical and electronic characteristics of GeC/g-C3N4 vdW heterostructures (vdWHs) with four different stacking patterns using first-principles calculations. The phonon spectra, interlayer distance, binding energies and ab initio molecular dynamics calculations show the kinetic, mechanical, and thermal stability of GeC/g-C3N4 vdWH after hydrogenation at 300, 500 and 800 K and possesses anisotropic Poisson's ratio, Young's and bulk modulus, suggesting that it's a promising candidate for experimental fabrication. According to an investigation of its electronic properties, GeC/g-C3N4 vdWH has a bandgap of 1.28 eV, but hydrogenation dramatically increases it to 2.47 eV. As a result of interface-induced electronic doping, the electronic states in g-C3N4 might be significantly adjusted by coming into contact with hydrogenated GeC sheets. The vdWH exhibits a type-II semiconductor, which can enhance the spatial separation of electron-hole pairs and has a strong red-shift of absorption coefficient than those of the constituent monolayers. The high potential drop caused by the significant valence and conduction band offsets effectively separated the charge carriers. The absorption coefficient of GeCH2/g-C3N4 vdWH is highly influenced by a biaxial compressive strain more than the biaxial tensile strain. Our theoretical research implies that the hydrogenated GeCH2/g-C3N4 vdWH possesses tunable optical and electronic behaviour for use as a hole-transport material in solar energy harvesting, nanoelectronic and optoelectronic devices.

Cu@CuOx/WO3 with photo-regulated singlet oxygen and oxygen adatoms generation for selective photocatalytic aromatic amines to imines

Photocatalysts can absorb light and activate molecular O2 under mild conditions, but the generation of unsuitable reactive oxygen species often limits their use in synthesizing fine chemicals. To address this issue, we disperse 1 wt% copper on tungsten trioxide (WO3) support to create an efficient catalyst for selective oxidative coupling of aromatic amines to imines under sunlight irradiation at room temperature. Copper consists of a metallic copper core and an oxide shell. Experimental and density functional theory calculations have confirmed that Cu2O is the primary activation site. Under λ < 475 nm, the light excites electrons of the valence bands in Cu2O and WO3, which activate O2 to superoxide radical •O2−. Then rapidly transforms into oxygen adatoms (•O) and oxygen anion radicals (•O−) species on the surface of Cu2O. Simultaneously, it is captured by holes in the WO3 valence band to generate singlet oxygen (1O2). •O bind to 1O2 promoting the coupling reaction of amines. When λ > 475 nm, intense light absorption due to the localized surface plasmon resonance excites numerous electrons in Cu to promote the oxidative coupling with the adsorbed O2. This study presents a promising approach towards the design of high-performance photocatalysts for solar energy conversion and environmentally-friendly oxidative organic synthesis.

Interfacial electric field competition in strain-modulated MoSTe/Hf2CO2: Inducing a direct-Z scheme charge transfer pathway for overall water splitting

The key to high-performance photocatalysts is efficient charge separation and easy regulation. A two-dimensional (2D) MoSTe/Hf2CO2 heterojunction has been proposed using density-functional theory (DFT), and the charge transfer path of the direct-Z scheme has been realized in the presence of strain. Importantly, the MoSTe/Hf2CO2, with its abundant tunability, is able to effectuate the transition from Type–II–A → Type-I → Type–II–B → direct Z-scheme → Type-III. In particular, under +2% and +3% biaxial strains, the band gaps of MoSTe/Hf2CO2 heterojunction are 0.335 and 0.024 eV, respectively, smaller than those of conduction band offset (CBO) and valence band offset (VBO), which favors the recombination of interlayer carriers and thus the formation of direct Z-scheme heterojunctions. While the charge transfer at the interface is subjected to two interfacial electric fields (IEF), IEFMoSTe and IEFInterface, which have obvious competition, the tensile strain leads to the enhancement of the interlayer coupling, which in turn strengthens the competitive advantage of the IEFInterface of the heterojunction. Moreover, the Gibbs free energy in hydrogen evolution reaction (HER) of the MoSTe/Hf2CO2 at a strain of +3% is very near to 0, meeting the requirements for an ideal photocatalyst. In this study, not only is a high-performance direct-Z scheme photocatalyst that can undergo overall water splitting proposed but also the abundant tunability of this heterojunction will have great application prospects in optoelectronic devices.

Heterojunction PdO/CoS as a High-Performance Visible-Light Active Photocatalyst Elimination of Methylene Blue from Aqueous Media

Heterojunction PdO/CoS as a High-Performance Visible-Light Active Photocatalyst Elimination of Methylene Blue from Aqueous Media

Hollow spherical covalent organic framework supported gold nanoparticles for photocatalytic H2O2 production

Covalent organic frameworks (COFs) are porous crystalline materials with promising applications in photocatalysis, but their performance is greatly hampered by the fast recombination of photogenerated carriers. Herein, a hollow spherical COF was synthesized via the condensation polymerization of 1,3,5-tris(4-aminophenyl)benzene and 1,3,5-benzenetricarbaldehyde, and Au nanoparticles were in-situ deposited onto the COF through NaBH4 reduction to ameliorate the photocatalytic performance. The composite exhibits impressive photocatalytic H2O2-production performance with the highest H2O2-evolution rate of 6067 μmol g−1 h−1 under visible light irradiation, which is about 1.9 times that of the pristine COF. The enhanced photocatalytic activity was ascribed to improved light absorption, abundant active Au sites, and efficient transfer and separation of photogenerated carriers in space. This work provides an avenue for designing high-performance H2O2-production photocatalysts by decorating porous COFs with active noble-metal sites.

0D/3D heterostructure of perovskite Cs2CuBr4 quantum dots/Bi2O3 microflower as a step-scheme photocatalyst for enhanced CO2 reduction

Exploring highly-efficient photocatalytic materials to convert CO2 into clean energy fuels is of great significance. Herein, lead-free perovskite Cs2CuBr4 quantum dots (QDs) were loaded onto Bi2O3 microflower to construct a 0D/3D heterostructure of Cs2CuBr4/Bi2O3 (CCB/Bi2O3) for photocatalytic CO2 reduction reaction (CO2 RR). The developed 0D/3D CCB/Bi2O3 heterostructure exhibited dramatically enhanced CO2 RR activity, with an electron consumption rate (Relectron) up to 322.12 μmol g−1h−1, which was 3.16 folds that of pure Cs2CuBr4 QDs. The improvement of CO2 RR activity was originated from the promoted carrier separation and transfer, as well as retainment of strongly reducing electrons induced by the step-scheme electron transfer mode, as authenticated by in-situ X-ray photoelectron spectra (XPS), electron paramagnetic resonance (EPR), and density function theory (DFT) calculation. The CO2 RR pathway was unveiled by in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The innovation of perovskite QDs-based step-scheme heterostructures can throw inspiration on designing high-performance photocatalysts applied in artificial photosynthesis.

Enhanced photocatalytic activity of BiOCl/BiOBr/SnS2 heterojunction using a superfine SnS2 and double S-scheme

Photocatalysis is a green approach to solving energy and environmental problems, and researchers are still pursuing high-performance photocatalysts. Although BiOX (X = Cl or Br) has a suitable bandgap and good stability, its photoresponse is mostly concentrated in the UV region. Conversely, SnS2 has a wide photoresponse range but exhibits perceptible photocorrosion and poor stability. To exploit the advantages of both BiOX and SnS2, this study hydrothermally synthesized and introduced superfine SnS2 (∼30 nm in size) into a BiOCl/BiOBr binary system to fabricate BiOCl/BiOBr/SnS2 composites. Subsequently, the degradation performance of these composites in a Rhodamine B solution under visible light was investigated. Results show that the BiOCl/BiOBr/SnS2 heterojunctions were successfully prepared and the composites exhibited the best photocatalytic performance with 6% mass fraction of SnS2 (BiOCl-to-BiOBr mol ratio = 1:1). The formation of a double S-schedule heterojunction between BiOCl/BiOBr and SnS2 not only accelerated charge separation and transfer but also broadened the photoresponse range and reduced photoelectron–hole recombination under full-spectrum irradiation. Loading a small narrow-bandgap photocatalyst onto a large photocatalyst provides an effective way to construct heterojunctions with excellent photocatalytic performance. The ternary photocatalyst presents a favorable photocatalytic stability, and its photodegradation rate is 4.6, 4.5 and 220.5 times that of BiOCl, BiOBr and SnS2, respectively.

Construction synergetic adsorption and activation surface via confined Cu/Cu2O and Ag nanoparticles on TiO2 for effective conversion of CO2 to CH4

High-performance photocatalysts for catalytic reduction of CO2 are largely impeded by inefficient charge separation and surface activity. Reasonable design and efficient collaboration of multiple active sites are important for attaining high reactivity and product selectivity. Herein, Cu-Cu2O and Ag nanoparticles are confined as dual sites for assisting CO2 photoreduction to CH4 on TiO2. The introduction of Cu-Cu2O leads to an all-solid-state Z-scheme heterostructure on the TiO2 surface, which achieves efficient electron transfer to Cu2O and adsorption and activation of CO2. The confined nanometallic Ag further enhances the carrier’s separation efficiency, promoting the conversion of activated CO2 molecules to •COOH and further conversion to CH4. Particularly, this strategy is highlighted on the TiO2 system for a photocatalytic reduction reaction of CO2 and H2O with a CH4 generation rate of 62.5 μmol∙g−1∙h−1 and an impressive selectivity of 97.49 %. This work provides new insights into developing robust catalysts through the artful design of synergistic catalytic sites for efficient photocatalytic CO2 conversion.

The physical properties and photocatalytic activities of green synthesized ZnO nanostructures using different ginger extract concentrations

The green synthesis method which is aligned with the sustainable development goals (SDGs) theory, is proposed to synthesize ZnO nanoparticles using ginger extract to treat the acidic wastewater and acidic factory effluent as a current challenge and the effects of the concentration of extracts on the synthesized ZnO nanostructures are investigated. The results declare that the single-phase hexagonal ZnO is formed using ginger extract concentration of less than 25 mL and the crystallite size of green synthesized ZnO NPs increased with increasing the concentration of ginger extract. Also, the significant effects of ginger extract concentration on the morphology of nanoparticles (nanocone, nanoflakes, and flower-like) and the particle size are demonstrated. The low concentration of ginger extract leads to the formation of the ZnO nanoflakes, while the flower-like structure is gradually completed by increasing the concentration of the ginger extract. Furthermore, significant changes in the specific surface area (SSA) of the samples are observed (in the range of 6.1–27.7 m2/g) by the variation of ginger extract concentration and the best SSA is related to using 10 mL ginger extract. Also, the strong effect of using ginger extract on the reflectance spectra of the green synthesized ZnO NPs, especially in the UV region is proved. The indirect (direct) band gap energies of the ZnO samples are obtained in the range of 3.09–3.20 eV (3.32–3.38 eV). Furthermore, the photocatalytic activities of the samples for the degradation of methylene blue indicate the impressive effect of ginger extract concentration on the degradation efficiency of ZnO nanoparticles and it reaches up to 44% and 83% for ZnO NPs prepared using 5 mL ginger extract in a pH of 4.3 and 5.6, respectively. This study provided new insights into the fabrication and practical application of high-performance ZnO photocatalysts synthesized using ginger extract in degrading organic pollutants in an acidic solution.

Benzotrithiophene-based covalent organic frameworks as efficient catalysts for artificial photosynthesis of H2O2 in pure water

Direct synthesis of hydrogen peroxide (H2O2) using oxygen and water through the photocatalytic route is a prospective approach for the on-site production of H2O2. However, the limited varieties of photocatalytic sites and ambiguous structure-active relationship impede the development of environmentally friendly technology. Herein, we report a active compound (benzotrithiophene, BTT) for the photosynthesis of H2O2 using oxygen and water, and design four benzotrithiophene-based 2D covalent organic frameworks (BTT-COFs) linked with aromatic amines linkers. Significant enhancement in photocatalytic activity has been observed via the introduction of BTT struct into 2D COFs. The high crystallinity of COFs increases the visible light absorption ability and photostability of BTT. The suitable distance of BTT struct in COFs and the construction of donor–acceptor (D-A) structure further promote the carrier generation and transfer. The COF-BTT-TAPT exhibited the highest H2O2 production rate of 620 μmol g−1 h−1. Mechanism investigation experiments have given the validation that BTT-COFs efficiently reduce oxygen in pure water to form H2O2 under visible-light irradiation. This work paves a revolutionary way for designing and fabricating high-performance metal-free photocatalysts for visible-light-driven H2O2 production.

Synergistic effect of Cu doping and Z-scheme heterojunction on ZnIn2S4/Cu-doped WO3·0.5H2O for boosting photocatalytic H2 evolution

The key to realizing efficient hydrogen production driven by sustainable solar is to develop high performance photocatalysts. Herein, a ZnIn2S4/Cu-doped WO3·0.5H2O (ZIS/Cu-WO) heterojunction was synthesized and the synergy between Cu doping and Z-scheme heterojunction in hydrogen production was explored. The synthesized (ZIS/Cu-WO) has a special octahedral structure. The doping of Cu ions can induce the localized surface plasmon resonance (LSPR) of WO3·0.5H2O, which extends the spectral response range and improves charge conduction. After growing ZnIn2S4 (ZIS), the optimal ZIS/Cu-WO photocatalyst shows a remarkable H2 production rate of 3084 μmolg-1h-1, which is 7.0 times than undoped ZnIn2S4/WO3·0.5H2O (ZIS/WO). The enhanced photocatalytic hydrogen production performance is attributed to the synergistic effect of Cu doping and Z-scheme heterojunction, which further accelerated the separation of photogenerated electron holes. Moreover, the Z-scheme photogenerated charge transfer mechanism was confirmed, and the ZIS/Cu-WO heterojunction exhibits superior stability in 16 h cycle test. This study provides a valuable reference in designing metal ion-doped heterojunction photocatalysts.

Biogenic Punica granatum Flower Extract Assisted ZnFe2O4 and ZnFe2O4-Cu Composites for Excellent Photocatalytic Degradation of RhB Dye.

Globally, the textile industry contributes to pollution through accidental discharges or discharge of contaminated wastewater into waterways, significantly affecting water quality. These pollutants, including dye molecules, are environmental hazards for aquatic and terrestrial life. The field of visible light-mediated photocatalysis has experienced rapid growth, driven by the utilization of photocatalysts that can absorb low-energy visible light and effectively degrade dyes. In the present study, we report a simple method to controllably synthesize Fe2O3, ZnO, and ZnFe2O4 using the one-pot synthesis method. In the subsequent step, copper (Cu) was deposited on the surface of ZnFe2O4 (forming ZnFe2O4-Cu) using a facile, green, and cost-effective method. The synthesized samples were characterized using various techniques, including XRD, UV-Vis DRS, FT-IR, SEM-EDX, HR-TEM, XPS, PL, and BET analysis. These techniques were employed to investigate the composition, morphology, structure, and photophysical properties of as-prepared samples. The ZnFe2O4-Cu nanocomposite demonstrated efficient photocatalytic activity for degrading RhB dye pollutants under visible light. The photocatalyst was successfully reused for three consecutive cycles without significantly decreasing performance. Furthermore, during the study, the radical scavenging test emphasized the role of different radicals in the degradation of dye pollutants. This research has the potential to enable the efficient production of high-performance photocatalysts that can rapidly eliminate ecologically harmful dyes from aqueous solutions.

Synergistic exploration of dye degradation and pulse photoresponse using MoS2 nanosheets: Towards sustainable remediation and optoelectronic advancements

Two essential areas of research with important implications for environmental cleanup and optoelectronic device applications are dye degradation and the comprehension of the pulse photo-response of transition metal dichalcogenide (TMDC) materials. Using MoS2 Nanosheets, this study evaluates the pulse photo-response characteristics of dyes and their degradation mechanisms. The article focuses into the effectiveness of MoS2 materials in dye removal as well as their function in photocatalytic degradation processes. Additionally, the MoS2 nanosheets are easy to utilise in solutions containing methylene blue (MB) and can be used as a high-performance recyclable photocatalyst to photodegrade organic dyes like methylene blue (MB) in around 120 min when exposed to light. The pulse photoresponse behaviour of MoS2 Nanosheets (NSs) is also investigated, with an emphasis on their distinct charge carrier dynamics and potential uses in ultrafast photodetectors. The working electrodes constructed from MoS2 nanosheets demonstrate an obvious photovoltaic effect with a photocurrent of 6.920 A/cm2 at zero bias and 100 mW/cm2 of polychromatic light. Due to optimal conditions, the maximum photoresponsivity of 5.669 mA/W and Detectivity of 7.708 × 108 Jones is achieved. The intention is to provide details on the way dye degradation and pulse photo-response interact synergistically in MoS2 nanosheets and highlight their potential for improved optoelectronic devices and environmentally friendly remediation.

Efficient and stable visible-light-driven Z-scheme overall water splitting using an oxysulfide H2 evolution photocatalyst

So-called Z-scheme systems permit overall water splitting using narrow-bandgap photocatalysts. To boost the performance of such systems, it is necessary to enhance the intrinsic activities of the hydrogen evolution photocatalyst and oxygen evolution photocatalyst, promote electron transfer from the oxygen evolution photocatalyst to the hydrogen evolution photocatalyst, and suppress back reactions. The present work develop a high-performance oxysulfide photocatalyst, Sm2Ti2O5S2, as an hydrogen evolution photocatalyst for use in a Z-scheme overall water splitting system in combination with BiVO4 as the oxygen evolution photocatalyst and reduced graphene oxide as the solid-state electron mediator. After surface modifications of the photocatalysts to promote charge separation and redox reactions, this system is able to split water into hydrogen and oxygen for more than 100 hours with a solar-to-hydrogen energy conversion efficiency of 0.22%. In contrast to many existing photocatalytic systems, the water splitting activity of the present system is only minimally reduced by increasing the background pressure to 90 kPa. These results suggest characteristics suitable for applications under practical operating conditions.

Advanced quasi-2D amorphous TiOx-Au photocatalyst: Harnessing defects and carriers transport to boost visible-light organic pollutants degradation

Amorphous materials have recently garnered significant interest due to their low-cost fabrication methods, extensive surface area and plentiful surface defects, which offer numerous active sites for catalytic reactions. However, carriers self-trapping and recombination caused by bulk defects limit the employment of amorphous materials as photocatalysts. As such, it is essential to adjust the structure and defects to improve carriers utilization for creating high-performance amorphous photocatalysts. In this study, we developed a novel and facile strategy to fabricate a quasi-2D amorphous crepe-like TiOx-Au (cTiOx-Au) photocatalyst, in which the cTiOx was synthesized simply through one-step hydrolysis method at room temperature by constructing discrete reaction system with mass-confinement of the precursor to guide the morphology of the cTiOx. The removal efficiencies of the cTiOx-Au to antibiotic tetracycline (TC) and gaseous pollutant formaldehyde (HCHO) under visible light were 84.43 % and 95.92 %, respectively, which greatly surpassed those of its counterparts, normal amorphous TiOx (amTiOx)-Au (54.32 % and 73.67 %) and crystalline catalyst TiO2-P25-Au (49.29 % and 54.03 %). The remarkable visible-light photocatalytic capacity of cTiOx-Au can be attributed to the unique quasi-2D morphology of cTiOx. The ultrathin nanostructure not only maximizes surface defects and minimizes bulk defects, but also effectively shortens the carriers transport time and reduces recombination probability, on the other hand, it provides ample adsorption sites and accessible binding sites for plasmonic Au nanoparticles to amplify the effect of surface plasmon resonance enhancement. The excellent photocatalytic performances of cTiOx-Au for removing both aqueous and atmospheric pollutants endow it great potential in real environmental remediation applications.

Rational design of Bi2Sn2O7/Bi5O7I S-scheme heterojunction for visible photocatalytic oxidation of emerging pollutants

The construction of an S-scheme heterostructure is considered as a promising strategy for enhancing photocatalytic performance. Herein, a three-dimensional Bi5O7I (BOI) microsphere decorated with Bi2Sn2O7 (BSO) nanoparticles was prepared for the first time via a simple ultrasonic-assisted electrostatic self-assembly strategy and used for the degradation of 2,4-dinitrophenylhydrazine. 3 wt% Bi2Sn2O7/Bi5O7I has the highest degradation activity (93.7 %), with an apparent rate constant of 0.0848 min−1, which is 2.55 times that of the original Bi5O7I (0.0333 min−1). Moreover, the optimal binary heterojunction photocatalyst has good reusability and universal applicability. The results of cyclic voltammetry tests clarify that the optimal photocatalyst can provide more surface reactive sites. The results of radical trapping experiments and electron spin resonance indicate that holes (h+) and superoxide radicals are the main active radicals in the degradation process of 2,4-dinitrophenylhydrazine. Photoelectrochemical and photoluminescence confirm that 3 wt% Bi2Sn2O7/Bi5O7I composites exhibit the highest separation rate of photogenerated carriers. Finally, based on the results of experimental studies and theoretical calculations, the S-scheme charge transfer path on Bi2Sn2O7/Bi5O7I composite is determined. This work provides a new perspective on how to design high-performance S-scheme bismuth oxyhalide-based heterojunction photocatalysts for solar energy conversion.

Upconversion Material-Plasmonic Metal-Semiconductor Ternary Heteronanostructures for Wide-Range Solar-to-Chemical Energy Conversion.

Harvesting full-spectrum solar energy is a critical issue for developing high-performance photocatalysts. Here, we report a hierarchical heteronanostructure consisting of upconverting, plasmonic, and semiconducting materials as a solar-to-chemical energy conversion platform that can exploit a wide range of sunlight (from ultraviolet (UV) to near-infrared). Lanthanide-doped NaYF4 nanorod-spherical Au nanocrystals-TiO2 ternary hybrid nanostructures with a well-controlled configuration and intimate contact between the constituent materials could be synthesized by a wet-chemical method. Notably, the prepared ternary hybrids exhibited high photocatalytic activity for the H2 evolution reaction under simulated solar and near-infrared light irradiation due to their broadband photoresponsivity and strong optical interaction between the constituents. Through systematic studies on the mechanism of energy transfer during the photocatalysis of the ternary hybrids, we revealed that upconverted photon energy from the upconversion domain transfers to the Au and TiO2 domains primarily through the Förster resonance energy transfer process, resulting in enhanced photocatalysis.

Construction of CdS@g–C3N4 heterojunction photocatalyst for highly efficient degradation of gaseous toluene

Exploring efficient photocatalysts for the degradation of VOCs under visible light is a challenge. CdS@g–C3N4 heterojunction photocatalytic materials were developed in this study using a microwave-assisted sol-gel process. CdS@g–C3N4(0.2) photocatalyzed the maximum degradation of gaseous toluene under visible light irradiation, and the time required to achieve the same degradation rate was reduced by 270 min when compared to pure CdS. The morphological characterization, photoelectric property analysis, and DFT calculations all verified that the CdS nanoparticles were uniformly disseminated on the surface of g–C3N4, and that the interfaces were closely contacted to form a heterojunction interface with a built-in field. This enhances charge transfer from CdS to g–C3N4 while successfully decreasing electron-hole pair recombination caused by light. Furthermore, the energy band structure was altered to absorb longer wavelengths of light and extend the absorption spectral range, improving the photocatalytic material's efficacy for broad-spectrum light such as sunshine. This paper proposes methods for predicting and optimizing the surface structure of catalysts, as well as developing high-performance multi-heterojunction photocatalysts for the degradation of indoor VOCs.

Theoretical investigation of 2D/2D van der Waals SbPO4/BiOClxBr1-x heterojunctions for photocatalytic water splitting.

Bismuth halogenoxide (BiOX)-based heterojunctions have garnered considerable attention recently due to their potential to enhance photocatalytic performance. However, the predominant focus on II-type heterojunctions has posed challenges in achieving the requisite band edge positions for efficient water splitting. In this investigation, stable van der Waals SbPO4/BiOClxBr1-x heterojunctions were constructed theoretically by using density-functional theory (DFT). Our findings demonstrate that SbPO4 can modulate the formation of Z-scheme heterojunctions with BiOClxBr1-x. The structural properties of BiOX were preserved, while reaching excellent photocatalytic capabilities with high redox capacities. Further investigation unveiled that the band edge positions of the heterojunctions fully satisfy the oxidation-reduction potential of water. Moreover, these heterojunctions exhibit notable absorption efficiency in the visible range, with absorption increasing as x decreases. Our research provides valuable theoretical insights for the experimental synthesis of high-performance BiOX-based photocatalysts for water splitting, leveraging the unique properties of SbPO4. These insights contribute to the advancement of clean energy technology.