Visible Light Response Research Articles

Effect of synthesis temperature on the properties and photocatalytic performance of peroxo-titanate nanotubes prepared by bottom-up synthesis method

The alkaline treatment synthesis of titania/titanate nanotubes (TNTs) requires highly concentrated alkaline solutions (≥ 10 mol/L), which pose environmental and productivity limitations. In contrast, a bottom-up synthesis method for peroxo-titanate nanotubes (PTNTs) has been developed. This method offers two advantages: it can synthesize materials using low-concentration alkaline solutions (1.5 mol/L) and produce photocatalytic materials that are responsive to visible light. In general, the higher the crystallinity of a catalyst, the better its properties. However, PTNTs synthesized at temperatures close to their boiling point (around 100 °C) exhibit low crystallinity. This study hypothesizes a hydrothermal synthesis method at higher temperatures will enhance the crystallinity and photocatalytic performance of PTNTs, synthesizing them at temperatures ranging from 120 to 200 °C using a method capable of exceeding the boiling point. Higher synthesis temperatures resulted in improved morphological and crystallographic properties of the PTNTs. However, the formation of peroxo-bonding, crucial for visible light responsiveness, decreased. Nevertheless, peroxo-bonding formation was still achievable at the highest temperature of 200 °C, and the sample exhibited the best Rhodamine B (Rh B) photodegradation performance under visible light due to its enhanced specific surface area and crystallinity. This study highlights the novelty and environmental significance of hydrothermally synthesized PTNTs as superior photocatalysts by optimizing the synthesis temperature while using lower concentration alkaline solutions.

Photocatalyst for Antibiotics Degradation by In Situ Growth of Direct Z-Type Bi2S3/Bi4Ti3O12 Heterojunction.

Effective removal of antibiotics from aqueous solutions has emerged as a hot research topic in wastewater treatment. Photocatalytic degradation of antibiotics is one of the most effective methods to reduce ecological damage and environmental pollution. In this work, a novel photocatalyst consisting of Z-type heterojunction Bi2S3/Bi4Ti3O12 (BS/BTO) with visible light responses was prepared by an in situ growth method, and the obtained material was used for the degradation of tetracycline hydrochloride (TC). The best performing photocatalyst was BS/BTO-2, which exhibited high photocatalytic activity. The rates of TC degradation reached 97.9% within 40 min of illumination. The photocatalyst demonstrated a high stability and reproducibility even after 5 cycles. Electron spin resonance (EPR) tests and quenching experiments established that ·O2- and h+ were the main species responsible for the elimination of TC. On the basis of theoretical calculations and experimental data, a possible mechanism for the photocatalytic degradation of TC has been proposed. The heterojunction structure, which effectively increases the visible light absorption range and decreases the compounding efficiency of photogenerated electrons and holes, is principally responsible for the photocatalytic performance of BS/BTO. Additionally, liquid chromatography-mass spectrometry (LC-MS) was utilized to investigate the formation and degradation of reaction intermediates. The nontoxicity of the solution after tetracycline degradation was verified by cultivating wheat seeds. This work offers guidance for bismuth-based photocatalysts in the field of sustainable wastewater treatments.

Fabrication of g-C3N4 wrapped CAU-17 for efficient photocatalytic H2O2 production

Recently, photocatalytic production of H2O2 by semiconductors emerges as a green and potential method for green and sustainable H2O2 synthesis. In this work, a g-C3N4/CAU-17 composite with heterojunction structure was fabricated. There is a tight interface contact between g-C3N4 and CAU-17. And the g-C3N4 nanosheets was uniformly wrapped on CAU-17 surface. In the hybrid catalyst, CAU-17 provides a high surface area for g-C3N4 dispersion and the integration of g-C3N4 boosts the visible light response. Results showed that the H2O2 yield is 419.0 μmol.L-1.h-1 over g-C3N4/CAU-17 sample, which is 1.59 and 7.83 fold enhancements to bare g-C3N4 and CAU-17 counterparts. This work sheds light on the design of CAU-17-based composite photocatalysts and provides insights into H2O2 synthesis.

A Novel BiOBr/CAU-17 Composite with Enhanced Photo-Catalytic Performance for Dye Degradation and Removal of Tetracycline Antibiotic Under Visible Light.

In order to improve the low specific surface area and high recombinant light generation carriers of BiOBr, loading BiOBr onto suitable Metal Organic Frameworks (MOFs) is an effective strategy to unleash its efficient visible light response and intrinsic catalytic activity. In this study, using classic MOF CAU-17 as a precursor, using a straightforward co-precipitation technique, four BiOBr/CAU-17 composites with distinct MOF contents values BCAU-1, BCAU-2, BC, AU-3, and BCAU-4 were created, and their photo-catalytic characteristics were examined. The BCAU-2 composite exhibited much higher photo-catalytic degradation efficiency for Rhodamine B (RhB) and Tetracycline (TC) than the pristine materials, counter compositions, and early reported materials. XRD, SEM, TEM, XPS, and EDX results revealed the strong synergistic photo-catalytic effect of BiOBr and CAU-17. The photocatalytic degradation of TC was significantly enhanced by the BiOBr bimetal modification, with the 2 wt.% BiOBr/CAU-17 nanocomposite achieving an 87.2 % degradation of TC and 82 % Total Organic Carbon (TOC) removal within 60 min. The high photo-degradation efficiency of BCAU-2 composite should be attributed to the efficient transfer of photo-generated carriers at interfaces and the synergistic effect between BiOBr/CAU-17. Furthermore, the experiments on the capture of the active species proved that the main active free radicals involved in the degradation of RhB and TC are attributed to the photo-induced holes h+ and ⋅ O2 - under visible light. The catalyst's efficacy is corroborated by the outcomes of photoluminescence spectroscopy and photo current response. This study offers a new understanding for the design of green synthesis schemes for photo-catalytic dye degradation and removal of certain antibiotics from the aquatic environment.

Engineering sulfur doped flower-like BiOBrxI1-x solid solutions for strengthened photocatalytic activities

In this work, a series of S-doped BiOBrxI1-x solid solutions are fabricated via a simple and rapid solvothermal process. Various characterization techniques are used to thoroughly investigate the as-fabricated solid solutions. Interestingly, compared to BiOBrxI1-x, S-doped BiOBrxI1-x solid solutions exhibit a loose flower-like structure comprised of thinner nanosheets, which contributes to the enhanced specific surface area, as assessed by Brunauer-Emmett-Teller analysis. Furthermore, S-doped BiOBrxI1-x solid solutions reveal boosted visible-light response and rapid separation of photoinduced charge carriers, as verified by optical, photo-electrochemical, and electrochemical analysis. These lead to superior visible-light photocatalytic properties of S-doped BiOBrxI1-x solid solutions on pollutant removal, N2 fixation, and microplastic degradation. The crystal structure, morphology, and photocatalytic stability of the prepared samples are demonstrated by comparing their X-ray diffraction patterns, scanning electron microscopy images, and photocatalytic degradation as well as nitrogen reduction performance before and after six catalytic recycles. Furthermore, based on Density Functional Theory simulations, significant modifications in the band gap of BiOBrxI1-x solid solutions occur as iodine content increases while sulfur doping further refines the electronic features, which aligns with the results of Tauc plots. This research proves that S doping is a viable strategy for modulating the electronic structures of BiOBrxI1-x solid solutions for improving its photocatalytic performance, and provides a new route for optimizing the bandgaps of semiconductors via the non-metallic doping strategy.

High-efficiency and stable Z-scheme heterojunction of Co9S8 anchored by g-C3N4 for peroxymonosulfate activation

Photocatalytic technology and peroxymonosulfate (PMS) based advanced oxidation technology have been proven to be simple and effective strategies for recalcitrant organic pollutants degradation. In this work, we designed and prepared a coupled photocatalytic and advanced oxidation system for sulfamethazine (SMR) antibiotics degradation. Firstly, a series of Z-scheme Co9S8/g-C3N4 heterojunction photocatalysts are prepared by a simple two-step method and further work as PMS activators. The prepared Co9S8/g-C3N4 photocatalysts exhibit a great improvement in electron-hole pairs migration and visible-light response due to heterojunction formation. In addition, the g-C3N4 acts as a substrate to anchor the Co9S8 nanoparticle, which suppresses the Co9S8 leaching and prevents the Co9S8 oxidation. Consequently, the Co9S8/g-C3N4/PMS system displayed an improved SMR degradation ability (93 % for Co9S8/g-C3N4/PMS vs. 86 % for Co9S8/g-C3N4). After the fourth cyclic degradation experiment, the Co9S8/g-C3N4/PMS system still maintained a comparatively high degradation rate. Considering its good properties and better degradation performance, we propose that the synergistic effect of photocatalytic technology and PMS possess a promising prospect for application in environmental treatment.

Simultaneous Structural and Electronic Engineering on Bi- and Rh-co-doped SrTiO3 for Promoting Photocatalytic Water Splitting.

Activating metal ion-doped oxides as visible-light-responsive photocatalysts requires intricate structural and electronic engineering, a task with inherent challenges. In this study, we employed a solid (template)-molten (dopants) reaction to synthesize Bi- and Rh-codoped SrTiO3 (SrTiO3 : Bi,Rh) particles. Our investigation reveals that SrTiO3 : Bi,Rh manifests as single-crystalline particles in a core (undoped)/shell (doped) structure. Furthermore, it exhibits a well-stabilized Rh3+ energy state for visible-light response without introducing undesirable trapping states. This precisely engineered structure and electronic configuration promoted the generation of high-concentration and long-lived free electrons, as well as facilitated their transfer to cocatalysts for H2 evolution. Impressively, SrTiO3 : Bi,Rh achieved an exceptional apparent quantum yield (AQY) of 18.9 % at 420 nm, setting a new benchmark among Rh-doped-based SrTiO3 materials. Furthermore, when integrated into an all-solid-state Z-Scheme system with Mo-doped BiVO4 and reduced graphene oxide, SrTiO3 : Bi,Rh enabled water splitting with an AQY of 7.1 % at 420 nm. This work underscores the significance of simultaneous structural and electronic engineering and introduces the solid-molten reaction as a viable approach for this purpose.

Fabrication of double S-scheme Sr2MgSi2O7:Eu2+,Dy3+/ZnIn2S4/UiO-66-NH2 heterojunctions with photon storage effect for enhanced round-the-clock photocatalysis

Persistent light-emitting materials (PLMs), which have the potential to store and release light energy after light irradiation, are receiving increasing attention for their role in prolonging the lifetime of photogenerated electrons for the development of photocatalysts with round-the-clock applications. In this paper, a double S-scheme Sr2MgSi2O7:Eu2+,Dy3+/ZnIn2S4/UiO-66-NH2 (SZU) heterojunction with round-the-clock catalytic activity was prepared by hydrothermal self-assembly method. The photocatalytic performance of the SZU heterojunction for RhB(MB) degradation was significantly improved compared with the pristine ZnIn2S4 and UiO-66-NH2. The SZU heterojunction has excellent catalytic degradation performance for RhB (MB), and the removal rate of RhB (MB) reaches 72.2 % (81.7 %) after visible light irradiation for 40 (60) minutes. After the end of light, the total removal rate of RhB (MB) reached 86.7 % (96.8 %) when the catalysis continued for several hours under dark conditions, which was 14 % and 15 % higher than that under visible light irradiation, respectively. Based on the characteristics of SMS photoluminescence, combined with a large number of photocatalytic experiments, The sustained photocatalytic activity was enhanced under both daytime and darkness conditions, not only because of the production of SZU complexes, which prolonged the visible light response of ZnIn2S4, but also because of the construction of double S-scheme heterojunctions, which facilitates the light storage capacity, charge transfer, and the separation of photo-induced charge carriers and effectively promoted the photocatalytic activity of the photocatalysts. This work contributes to a deeper understanding of the design of round-the-clock photocatalysts, and provides a useful exploration for the practical application of photocatalytic technology.

Z-Schematic Water Splitting on Photocatalyst Sheets Composed of Transition-Metal-Doped Metal Oxides with Long Wavelength Visible Light Responses and a Conductive Polymer

Z-Schematic Water Splitting on Photocatalyst Sheets Composed of Transition-Metal-Doped Metal Oxides with Long Wavelength Visible Light Responses and a Conductive Polymer

Fabrication of efficient interface carrier channels on multidimensional O[sbnd]CQD Decorated CN Heterojunction for tetracycline degradation via peroxymonosulfate activation

Graphite carbon nitride (CN) is recognized as a promising non-metallic semiconductor photocatalyst for its excellent chemical stability and visible light response. However, the high electron-hole recombination rate in CN greatly limits its photocatalytic performance. To circumvent these limitations, it is particularly important to explore an efficient way to promote the migration of carriers in CN. This study innovatively designs a multidimensional heterojunction between organic carbon quantum (OCQD) and CN, which named as OCQD-CN. OCQD acts as an carriers transfer channel, which effectively promotes the separation efficiency of carriers. Meanwhile, the introduction of OCQD further improves light absorption scope as well as light reaction intensity of CN. By adding peroxymonosulfate (PMS) to form an advanced oxidation process, OCQD-CN10 exhibits a prominent tetracycline (TC) degradation capacity up to 89.1 % within 60 min. The photocatalytic degradation performance of OCQD-CN is significantly improved by 2.0 times with the addition of OCQD. The first-order rate constant corresponding of OCQD-CN10 (0.0300 min−1) is also 2.8 times higher than CN (0.0107 min−1). Thereby, this research underscores the potential of OCQD-CN/PMS system in mitigating water pollution and advancing eco-friendly technologies, offering a promising route to address antibiotic contaminants in the environment.

Microwave-assisted CuO-modified porous ZnO nanosheet for photocatalytic degradation of organic pollutants and antibacterial inactivation

The present study investigated the development of a porous ZnO/CuO photocatalyst for photocatalytic dye degradation and antibacterial inactivation of bacteria. Porous ZnO nanosheets are prepared by calcinating inorganic-organic ZnS(en)0.5. Further, CuO was integrated on a porous ZnO nanosheet using the microwave (MW)-assisted synthesis technique. Additionally, the effect of CuO at different concentrations on the photocatalytic activity of CuO/ZnO was investigated. Under 1.5G light illumination, an optimized ZnO/CuO-5 photocatalyst exhibited higher degradation efficiencies of 99.3%, 98%, and 99% for orange II dye, methylene blue (MB), and Eosin-Y respectively. The optimized photocatalyst exhibited inactivation efficiencies of 98% and 90% towards Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, after 3h. The enhanced photocatalytic activity was attributable to a porous structure, extended visible light responsiveness, and delayed electron-hole recombination in nanostructured CuO/ZnO photocatalysts. Moreover, radical scavenger tests confirmed that superoxide radicals (•O2−) accompanied most degradation, followed by holes (h+) as minor factors. Our work suggests a simple photocatalytic interfacial engineering technique based on porous ZnO/CuO nanostructures to decompose organic chemicals and inactivate microorganisms in wastewater sources.

Iron mediated n → π* electron transitions and mid-gap states formation in CN under low-temperature secondary calcination enhances photodegradation of organic pollutants

Iron modified carbon nitride (CN) materials have attracted widespread attention from researchers in different application fields. In this paper, single atom iron anchored CN (FeCN) with mid-gap states and n → π* electron transition was synthesized through low temperature secondary calcination. The mid-gap states introduce surface states capable of trapping photogenerated electrons, enabling FeCN to absorb photons with energies lower than its intrinsic optical bandgap. 10%FeCN also exhibits distinct optical absorption above 490 nm derived from the n → π* electron transition, which expand the visible light response range of photocatalysts and enhance electron transport ability. Additionally, the Fe-Nx site enhances the separation and transmission efficiency of photoexcited charges. The prepared 10%FeCN exhibits extremely high photocatalysis and photo-Fenton activity. Mercaptobenzothiazole (MBT) degradation rate of 10%FeCN is 3.47 times higher than CN, achieving a mineralization rate of 86.7% in 100 min. Additionally, the oxytetracycline hydrochloride (OTC) degradation rate of 10%FeCN in photo-Fenton reaction is 11.9 times higher than CN. After five cycles, this catalyst still has good reactivity, indicating its good stability.

A novel lanthanum-modified polytitanium chloride coagulant: Efficient algae removal and enhanced photocatalytic ability of recycled algal sludge

The removal of harmful cyanobacterial blooms (HCBs) and reuse of the resulting algal sludge are pressing issues in current environmental governance and ecological conservation. Aiming at tackling the above-mentioned challenges, titanium (Ti)-based coagulants are promising candidates. However, most of them suffer from poor stability and weak actual algal removal ability, and recycling of the algal sludge usually produces titanium dioxide (TiO2) with low photocatalytic ability. In this work, a lanthanum (La)-modified polytitanium chloride (La-PTC) coagulant is reported. La in the La-PTC coagulant serves a "kill two birds with one stone" strategy in algae removal and algae sludge reuse. Owing to the introduction of La ions, the La-PTC coagulant exhibits ultra-high stability and excellent algae removal capability with an efficiency of 98.71%, which is 7.25% higher than that of PTC coagulant. Moreover, recycling algae sludge can prepare high catalytic (2.45 times the commercial P25 TiO2) La/C-TiO2, where the presence of La enhances its visible light response range and inhibits electron hole recombination. The strategy of this La modified coagulant can not only achieve efficient removal of HCBs, but also transform the recovered algal sludge into photocatalysts with higher catalytic capacity.

Enhanced piezo-photocatalytic activity of ZnS/Fe2O3: Benefit from type I junction and weak water flow-induced piezoelectric polarization

Photocatalysis is considered to be a sustainable and less polluting environmental purification technology, however, the limited photogenerated charge separation efficiency and light absorption hinder its large-scale application. Encouragingly, piezocatalysis is proposed as an emerging and appealing strategy to drive the migration and separation of photoinduced carriers. Nevertheless, the source of piezocatalysis is usually derived from high energy-consuming ultrasonic vibration. Herein, we realize superior piezo-photocatalytic chlortetracycline hydrochloride degradation performance stimulated by low-frequency water flow-driven piezoelectric polarization of I-type ZnS/Fe2O3 junction. The integration of Fe2O3 is beneficial to extend the light absorption from ultraviolet region to visible range and boost the charge separation efficiency of ZnS/Fe2O3. Meanwhile, the piezoelectric polarization triggered by weak water flow further promotes the directional separation of photogenerated carriers. With all these merits, the optimized ZnS/Fe2O3 shows a piezo-photocatalytic chlortetracycline hydrochloride (CTC) degradation rate of 73.2 % within 20 min, which is 2.8 and 2.1 times that of Fe2O3 and ZnS, respectively, and 17.4-fold and 1.1-fold that of single stirring and light, respectively. This work provides a feasible guidance for designing efficient piezo-photocatalysts for in-situ purification of wastewater in natural environmental with effective visible light responsiveness and sensitivity to weak mechanical stress.

Hybridizing engineering strategy of decatungstate III: Transition metal modified carbon quantum dot-regulated photo-catalytic oxidation performance of decatungstate

The selective oxidation of hydrocarbons (RH) by dioxygen (O2) is a very important method for industrial production of bulk oxygen-containing compounds, However, due to the high chemical inertness of RH and O2, achieving this reaction under mild conditions still faces significant challenges. This paper discloses an efficient hybridizing engineering (HE) strategy of decatungstate (DT) with 3d transition metal ions (Mn+=Ni2+, Co2+ or Cu2+)-modified carbon quantum dots (Mn+/CQD) as the dopants. Compared to pure CQD, The Mn+/CQD can more efficiently combine with DT anion to fabricate a high-quality hybrid via electrostatic interactions, thereby bestowing the hybrid with an enhanced visible light response especially the separation efficiency of photo-generated charge pairs. Furthermore, the above hybridization effects of Mn+/CQD on DT anion can be fine-tuned and gradually improved with a change of the metal ion from Cu2+, Co2+ to Ni2+, along with a continuous enhancement of the hybrid's photo-catalytic efficiency in the visible light- triggered selective oxidation of ethylbenzene with O2 in acetonitrile. The best Ni2+/CQD-doped TBADT can achieve ca. 48% ethylbenzene conversion and 87.6% acetophenone selectivity in the presence of 2 M HCl, and it also shows a much higher photo-catalytic activity for the photo-oxidation of toluene, cyclohexane and benzyl alcohol compared to pure TBADT. The HE strategy with Mn+/CQDs as the cationized hybridizers is much superior to that with pure CQD or Ni2+ as the hybridizer in hoisting the photo-catalytic performance of DT.

High-efficiency photocatalytic hydrogen and oxygen evolution properties by Z-scheme electron transfer in BiVO4/C3N5 heterostructure

C3N5 has been identified as a prospective photocatalyst for hydrogen production, particularly due to its visible-light response capability. However, to enhance the photocatalytic activity efficiency of C3N5, effective charge separation is necessary. This study presents the fabrication of a novel BiVO4/C3N5 heterostructure via a practical in-situ oil bath approach. By incorporating BiVO4 as an oxidation-functional photocatalyst, a Z-scheme charge carriers migration mechanism is introduced to facilitate the spatial separation and prolong the lifetime of photoexcited charge carriers. Consequently, the BiVO4/C3N5 heterostructure exhibits a significantly enhanced photo-redox ability in contrast to pure C3N5, thereby promoting the overall photocatalytic performance. Notably, this work demonstrates, for the first time, the successful achievement of satisfactory hydrogen and oxygen production in the BiVO4/C3N5 system.

Visible-light-response organic-inorganic hybrid CdS/MIL-101-NH2 S-scheme heterostructures for high-efficient photo-Fenton application

Developing artificial-photosynthesized heterostructures for solar energy conversion has inspired extensive interest, but the organic-inorganic hybrid Fe-based MOF photocatalyst is still in shortage. Here we report a visible-light response CdS/MIL-101-NH2 hybrid S-scheme heterostructure to exhibit efficient photocatalytic and photo-Fenton functionalities under the simulated solar-driven irradiation. In our work, the 0D CdS nanoparticles have in-situ anchored on the 3D NM101 octahedron to form well interface connection by a mild and simple co-precipitation method, which effectively promoted to shorten the carrier transfer distance as well as to promote charge separation. The whole photo-physics process has been revealed by systemically characterizations and the artificial-photosynthesized S-scheme heterostructure has been confirmed by the results of electrochemical measurements and density functional theory (DFT) calculations. By comparison, the as-prepared CdS/MIL-101-NH2 photocatalysts have more potential applications in Fenton-like advanced oxidation techniques considering their stability and element with variable valency, furthermore, the corresponding mechanism has been discussed. Our work extends the territory of organic-inorganic hybrid heterostructures and hopes to provide a new viewpoint for fabricating efficient artificial-photosynthesized photocatalysts.

Visible light response SnFe2O4/BiOCl microspheres: Sysnthesis, magnetical and photocatalytic properties

The current two-dimensional (2D) BiOCl photocatalyst generally suffer from poor photocatalytic performance and low recovery efficiency, which is caused by its small size and response to UV-light only. In this paper, magnetic recyclable SnFe2O4/BiOCl (labelled as SFO/BOC) nanospheres with excellent photocatalytic properties (86 %TC, 91 %CIP) were successfully synthesized by a two-step solvothermal method for the first time and used for photocatalytic degradation of antibiotics. The results showed that SFO/BOC microspheres had high photodegradation efficiency (86.64 % and 90.68 %) and cyclic stability (74.63 % and 80.78 % after 5 cycles) for TC and CIP under visible light irradiation for 1 h. The photodegradation mechanism of SFO/BOC was discussed by the radical trapping experiments. This study provides a new type of photocatalytic materials for the development of high efficiency photocatalyst with excellent magnetic recovery.

Interface engineering of AgI/(P, K)-g-C3N4 novel S-scheme heterostructures as a highly efficient photocatalyst for RhB degradation

In this study, we developed an in-situ deposition method to load small-sized AgI nanoparticles as an oxidative photocatalyst (OP) onto phosphorus (P) and potassium (K) co-doped two-dimensional porous g-C3N4 (PK-CN-N) as a reductive photocatalyst (RP), forming an S-scheme heterojunction photocatalyst AgI/PK-CN-N. PK-CN-N achieved morphology control and element doping, leading to surface functionalization and heterostructure formation for the AgI/PK-CN-N photocatalyst. Notably, the 50AgI/PK-CN-N composite demonstrated an approximately 95 % removal efficiency for RhB within 30 minutes, 17.6 times higher than pure g-C3N4, surpassing most reported g-C3N4-based photocatalysts. The enhanced photocatalytic efficiency is attributed to the surface modification strategy and heterostructure formation of g-C3N4, which broadens the visible light response range, increases the number of active sites, improves the separation of photogenerated electron-hole pairs, and enhances REDOX capabilities. The band structure of the composite was elucidated through Mott-Schottky analysis and UV–vis DRS. The formation of the AgI/PK-CN-N S-scheme heterojunction and its charge transfer mechanism was confirmed through XPS, band structure analysis, KPFM, and EPR spectroscopy. Experimental data confirmed the presence of a strong and effective interface electric field between the two semiconductors, leading to band bending and accelerated charge separation. Additionally, the introduction of small-sized AgI semiconductors enhanced the exposure of the coupling interface, further improving catalytic performance. The reusability and lifespan of the catalyst were also analyzed, showing that after four cycles, the photocatalytic activity remained above 92 %.

Recent Research Progress on Surface Modified Graphite Carbon Nitride Nanocomposites and Their Photocatalytic Applications: An Overview

Semiconductors with visible light catalytic characteristics can realize the degradation of pollutants, CO2 reduction, and hydrogen preparation in sunlight. They have huge application value in the fields of environmental repair and green energy. Graphite phase nitride (g-C3N4, CN) is widely used in various fields such as photocatalytic degradation of pollutants due to its suitable gap width, easy preparation, low cost, fast visible light response, and rich surface activity sites. However, the absorption rate of ordinary CN on visible light is low, and the carriers are easy to recombination, making the lower optical catalytic activity. Therefore, in order to improve the photocatalytic characteristics of the CN, it is necessary to make the surface modification. This article first introduces several main methods for the current surface modification of CN, including size regulation, catalyst embedding, defect introduction, heterostructure construction, etc., and then summarizes the optical catalytic application and related mechanisms of CN. Finally, some challenges and development prospects of CN in preparation and photocatalytic applications are proposed.