Photocatalytic Reaction Research Articles

Visible light degradation of antibiotics catalyzed by nanoporous carbon/V2O5 nanocomposite: structural, optical and electrochemical properties

In this study, nanoporous carbon (NPC) decorated V2O5 (NPC/V2O5) nanocomposite synthesized by a hydrothermal technique using biomass-derived NPC nanoflakes towards the application of berberine hydrochloride (BH) dye degradation under visible light irradiation. The prepared samples were characterized by X-ray Diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray (EDX), UV-Visible and Photoluminescence (PL) spectroscopy. Charge transfer resistance was measured by electrochemical impedance spectroscopy (EIS) and liner sweep voltammetry (LSV). XRD studies confirm the orthorhombic crystal structure of NPC/V2O5 nanocomposite. FE-SEM and TEM analysis validate their particle-like and sheet-like morphology of V2O5 and NPC respectively. Further, UV-visible DRS and PL spectra of the green synthesized NPC/V2O5 nanocomposite exhibited a low band-gap and reduced recombination rate compared to the pure counterpart which is better light-absorbing ability in the visible light region. Batch experiments represent the incorporation of NPC and V2O5 would lead to an increase the photocatalytic performance of NPC/V2O5 toward BH dye degradation. During the photocatalytic reaction, the NPC/V2O5 nanocomposite degraded rate around 97.7% against BH dye within 80 min while pure V2O5 degraded 92.5% of BH dye under same visible light irradiation time. Finally, the cyclic stability experiment exhibits the photocatalyst even stable after five consecutive tests.

Toxicological and environmental risks of enalapril and their possible transformation products generated under phototransformation reactions

Pharmaceutical active compounds (PACs) in the concentration range of hundreds of ng/L to μg/L have been identified in urban surface water, groundwater, and agricultural land where they cause various health risks. These pollutants are classified as emerging and cannot be efficiently removed by conventional wastewater treatment processes. The use of nano-enabled photocatalysts in the removal of pharmaceuticals in aquatic systems has recently received research attention owing to their enhanced properties and effectiveness. In the current study, toxicological and environmental risks of enalapril (ENL) and their possible transformation products (TPs) generated under phototransformation processes (e.g., photolysis and photocatalysis reactions) were assessed. In photolysis reaction, removal of ENL was incomplete (< 16%), while mineralization degree was negligible. In contrast, total removal of ENL was achieved through the photocatalytic process and its maximum mineralization ratio was 66% by using natural radiation. Proposed transformation pathways during the phototransformation of ENL include hydroxylation and fragmentation reactions generating transformation products (TPs) such as hydroxylated TPs (m/z 393) and enalaprilat (m/z 349). Potential environmental risks for aquatic organisms were not observed in the concentrations of both ENL and enalaprilat contained in surface water. However, the acute and chronic toxicities prediction of TPs such as m/z 409, 363, and 345 showed toxic effects on aquatic organisms. Thus, more studies regarding TPs monitoring for both ENL and PhACs with highest occurrence worldwide are necessary for the creation of a database of the concentrations contained in surface water and groundwater for the assessment of the potential environmental risk for aquatic organisms.

Self-Sensitization-Induced Protonation Sites for Weak-Light-Driven Hydrogen Evolution in Coordination Polymers

The exploration on weak-light-driven catalysis is an important approach to reduce the dependence of photocatalysts on strong light and improve the efficiency of solar spectrum utilization. However, the reported photocatalysts typically necessitate high light intensity (e.g., exceeding 100mWcm−2) for catalytic reactions, which cannot be achieved with natural solar light. Herein, a self-sensitization-induced strategy was employed to generate in-situ proton sites, enabling photocatalytic hydrogen evolution reaction (HER) even under low light intensity (10mWcm−2). An indolocarbazole ligand (H2ICDB) was utilized to construct a paddle-wheel dicopper coordination polymer (CuICDB-DMF). By substituting the axially coordinated DMF with methanol or water, CuICDB-MeOH and CuICDB-H2O were obtained. Under weak-light irradiation (10mWcm−2), CuICDB-H2O exhibited the highest photocatalytic HER rate of 838.4 μmol g−1 h−1 when compared to the other two counterparts. Remarkably, the substitution of axially coordinated H2O promotes charge separation and transfer efficiency through optimizing ligand-to-cluster charge transfer (LCCT) process. Moreover, density functional theory (DFT) calculations reveal that coordinated H2O substitution decreases the Gibbs free energy difference of the potential determining step (H2O* → OH* + H*) in CuICDB-H2O.

Development of soft x-ray absorption spectroscopy technique with simultaneous measurement in electron- and fluorescence-yield modes from high vacuum to ambient pressure for observation of surface adsorbed species.

To understand the reactions of heterogeneous catalysts at the solid-gas interface under actual reaction conditions, it is important to develop a method to observe the surface-adsorbed species during the reaction, including the changes before and after the adsorption of light elements involved in the surface reaction. We developed a soft x-ray absorption spectroscopy (XAS) technique that allows simultaneous measurements in the electron- and fluorescence-yield modes in the pressure range of 10-4-1 × 105Pa. In the developed system, the reaction gas near the sample surface is separated from the beamline vacuum by a Si3N4 window and confined to a small area to suppress x-ray absorption by the gas. The electron-yield spectra were obtained by measuring the sample current while applying a bias potential to the Si3N4 window. XAS measurements were performed from high vacuum to ambient pressure by setting the bias potential to 600 and 39V below and above 100Pa, respectively. An anatase TiO2 nanoparticle-deposited film was prepared by spin coating, and soft XAS was performed to observe the photocatalytic oxidative decomposition reactions of isopropanol in the presence of water and oxygen. The obtained O K-edge spectra showed that it is possible to observe adsorbed oxygen on solid oxides even under ambient pressure conditions containing 0.1% of oxygen gas.

Cross‐Electrophile Couplings (XECs) between Similar Electrophile Reagents

Comprehensive SummaryCross‐electrophile couplings (XEC), a crucial subset of cross‐coupling reactions, center on the formation of robust C—C bonds through the union of two electrophiles. Usually, such reactions have primarily been catalyzed by transition metals. However, with the steady advancements in photochemical and electrochemical technologies, XEC reactions have significantly progressed and broadened their scope, allowing for the utilization of a wider array of tolerable functional groups, thus revealing vast application prospects. This review aims to systematically summarize the current prevalent types of electrophiles and delve into their specific application examples within XEC reactions involving electrophiles with identical functional groups. Specifically, XECs between the same type of halides have received considerable attention, whereas carboxylic acids and alcohols are still in the early stages of investigation. Furthermore, certain other common electrophiles remain unexplored in this context. Moreover, this review underscores the remarkable contributions of photochemistry and electrochemistry in the field of XEC reactions, aiming to provide valuable insights and inspiration for researchers. Also, this review hopes to spark further interest in XEC reactions, thereby fueling the continuous development and advancement of this exciting area of research. Key ScientistsSince the 1960s, advancements in the XEC reaction have been substantial, driven primarily by the application of transition metal catalysts. In this area, many distinguished scientists have contributed their wisdom and efforts. Particularly noteworthy is that, during the systematic study of XEC reactions with the identical functional groups, in 2016, MacMillan achieved a photocatalytic XEC reaction between aryl bromides and alkyl bromides; in 2020, Weix successfully realized a nickel‐catalyzed XEC reaction between aryl chlorides and alkyl chlorides. Concurrently, contributions from researchers such as Mei, Wolf, Sevov, Lin, Shen, Browne, Zhang, and Qiu have expanded the scope of XEC reactions to various halides. By 2022, MacMillan and Baran achieved a significant milestone in the XEC between carboxylic acids, further broadening the scope of research in this area. Also, advancements in the XEC of alcohols have been noted, with researchers including Weix, Lian, Tu, and Stahl conducting pioneering work and successfully executing the XEC of protective groups. It is foreseen that the ongoing research endeavors will primarily concentrate on the expansion of diverse electrophiles.

Re3P4@C/TiO2 Ohmic junction Boosts charge carrier separation for photocatalytic hydrogen evolution

Construction of heterostructures featuring a well-designed transport pathway is pivotal in regulating the behavior of charge carriers, thereby achieving boosted separation efficiency. One of the primary factors leading to poor charge transfer and separation efficiency in heterostructures lies in the presence of interface barriers that hinder their transfer. Establishing an Ohmic contact with a low energy barrier can significantly reduce charge transfer resistance during photocatalysis. In this contribution, we have successfully developed an Re3P4@C/TiO2 Ohmic junction for highly improved photocatalytic H2 evolution rate, which exhibited a 68-fold increase compared to pristine TiO2. Experimental results combined with density functional theory calculations confirm the successful construction of Ohmic junction, which effectively facilitates the separation and transfer of photogenerated charge carriers while prolongs their lifetimes. This heterojunction also enhances the adsorption capacity for reactants and thus promotes the surface photocatalytic reactions. This work provides valuable insights into novel Ohmic junction construction to improve the photocatalytic activity.

Fabrication of core–shell nanostructure via novel ligand-defect reassembly strategy for efficient photocatalytic hydrogen evolution and NO removal

The core–shell structure often exhibits unique properties, resulting in superior physical and chemical performance distinct from individual component in the field of photocatalysis. However, traditional prepared methods such as template synthesis and layer-by-layer self-assembly are relatively complex. Therefore, it is necessary to explore an efficient and expedient approach. Here, we have proposed a convenient method to gradually destroy the terephthalic acid (BDC) of MIL-125 from the outer to inner layers through hydrothermal stirring, followed by reassembling with photosensitive 2-amino-terephthalic acid (BDC-NH2) into the exposed Ti-oxo clusters left by the BDC to create photocatalysts featuring a core–shell configuration. The special core–shell sample with the analogous mixture of MIL-125 and MIL-125-NH2 function as a high-performance dual-functional photocatalyst for hydrogen generation and NO elimination. The optimal core–shell material (M-125-45-N) exhibits an outstanding photocatalytic hydrogen production rate of 3.74 mmol·g−1·h−1 and an excellent photocatalytic NO removal rate of 70.15 %. The apparent quantum yield (AQY) value and solar-to-hydrogen energy conversion efficiency (STH) at specific wavelengths are also investigated. The Density functional theory (DFT) calculation, In-situ Fourier transform infrared (In-situ FT-IR) and Electron spin resonance (ESR) have suggested that the enhanced photocatalytic activity of optimal core–shell material arised from its stronger adsorption capacity towards reactants, promoting the production of reactive oxygen species (ROS) conducive to photocatalytic reactions. This study represents the first investigation of a dual functional core–shell MOFs formed via ligand-defect reassembly, showcasing the excellent efficacy in photocatalytic hydrogen evolution and NO removal, which contributes to the feasible development of novel dual-functional photocatalysts with core–shell structures.

Preparation of high-efficient donor-π-acceptor system with crystalline g-C3N4 as charge transfer module for enhanced photocatalytic hydrogen evolution

Donor-π-acceptor (D-π-A) type photocatalysts with g-C3N4 as π-module have attracted much attention due to their optimized conjugate structure and enhanced electron directed driving. However, the inefficient charges migration of g-C3N4 due to its amorphous or semi-crystalline structure and limitation of available functional groups are present challenges. In this work, the D-π-A type high crystalline carbon nitride (HCCN) has been obtained by in-situ introducing amide and cyanide groups into the high-crystallinity melon framework. The synergistic effect of functional group modification and crystallinity regulation greatly enhances the electron induction driving and charge carrier density. Moreover, the density functional theory calculations demonstrate that the D-π-A structure could induce the local charge distribution of melon units to provide a unique and stable pathway for photoinduced charges migration. The as-prepared HCCN sample shows a superior visible-light photocatalytic performance for hydrogen evolution with an apparent quantum efficiency (AQE) of 12.2 ​% at 420 ​± ​15 ​nm, which is 23.7 times higher than that of original g-C3N4. Finally, the charge separation and transfer processes as well as the possible photocatalytic reaction mechanisms of HCCN sample are also investigated.

Fluoro-polymer/TiO2 based photocatalysts for hydrogen generation

In view of limited number of studies on photoreforming of synthetic polymers, herein, a series of new glycopolymers are synthesized via RAFT polymerization to obtain diblock copolymers containing fluorinated and non-fluorinated segments in the glucopyranoside. These glycopolymers are used as probes to investigate photocatalytic reactions at different pH values of the modulated TiO2 photocatalyst. Through structural and surface characterizations, photocatalytic activities are investigated. Fluoro-polymers with deacetylated glucose, hydrophilic segment, PGD such as PPFPM-b-PGD and PPFBM-b-PGD could synergistically increase hydrogen generation rate up to 1368 μmol g-1h−1 and 1549 μmol g-1h−1 with quantum yields of 3.34 % and 3.79 % compared to non-fluoro glycopolymers. The presence of both fluorinated and non-fluorinated groups in diblock copolymers enhanced the rate of photocatalytic hydrogen generation compared to the homopolymer. The accelerated photo-reforming is attributed to in-situ fluorine-doped TiO2 along with high affinity and activation of water molecules. These polymers can generate hydrogen via photo-reforming process.

Tunable TiO2‐Heterophase Junctions for Studying and Enhancing Photocatalytic H2 Production Under Visible Light

AbstractPhotocatalytic performance of titanium dioxide under visible light was optimized by preparing heterophase compounds (containing two or more phases) by hydrolysis method using TiCl4 as a precursor with different concentrations (0.5, 0.7, 1, and 2) to adjust condensation modes of Ti4+. The structural and textural properties of the synthesized TiO2 multiphase were fully characterized by XRD, Raman scattering, FTIR, BET, MEB‐EDX, XPS, diffuse UV–vis, and EIS spectroscopy. The increase of TiCl4 amount precursor has a significant effect on the heterophase junctions of TiO2 structure and more especially on textural and structural properties. The best specific surface area (131 m2/g) is observed for the sample at high Ti‐content (2 in Ti4+). The anatase phase (79%) is detected only for 0.5 in Ti4+ sample. However, both rutile (R) and brookite (B) phases are present in 0.7, 1, and 2 Ti‐contents. On the one hand, the band gap of 2.9 eV allows titanium dioxide to be active under visible light. In addition, the presence of rutile/brookite heterophase junction contributes significantly to the improvement of active sites for photocatalytic reaction. The separation efficiency of photogenerated electrons and holes contributes to photocatalytic evolution performance under visible light for hydrogen production. The optimal sample (0.7 content in Ti+4 species) which presents in its structure 52% of rutile and 46% of brookite phases presented the highest photocatalytic activity with a 230 µmol/h of hydrogen generation, attributed to the heterophase junctions R52/B46, highly pore size 20.60 nm, and relatively small bandgap energy 2.974 eV. This work opens new horizons on the creation and study of a multiphase TiO2 that works under visible light in the fields of renewable energies and various other fields.

Surface self-modification of TiO2 for enhanced photocatalytic toluene oxidation via photothermal effect

Surface modification plays an important role in extending light absorption and enhancing the catalytic performance of semiconductor photocatalysts. However, most current studies focus on pre-modification of the semiconductors before reaction, while surface self-modification of catalyst during photocatalytic reaction process is often neglected. Here, we report the surface self-modification of TiO2 catalyst during photocatalytic oxidation of toluene under UV light irradiation, which changes the colour of TiO2 from white to yellow, and effectively extends its light absorption range into visible light region. The absorbed visible light is primarily released as thermal energy, significantly increasing the temperature of the catalytic system. Mechanistic studies reveal that the temperature elevation facilitates the separation of photogenerated charge carriers in TiO2 and promotes the generation of •O2−, consequently accelerating the surface redox reactions. The surface self-modified TiO2 exhibits an enhanced photothermal catalytic benzaldehyde generation of 4485 μmol g−1h−1 under UV–visible light irradiation, which surpasses the UV-driven activity of TiO2 by a factor of 1.9. This study offers new perspectives on the surface modification of semiconductor photocatalysts during organic transformations. It is anticipated to trigger increased research attention to this effect, ultimately advancing solar-to-chemical energy conversion.

Enhanced photocatalytic performance of TiO2 with tunable oxygen vacancies induced by H2/N2 mixture treatment

Surface treatment can effectively modulate the surface properties of a photocatalyst to hasten the separation and transfer of photoinduced charges, ultimately achieving high photocatalytic performance. Herein, surface treatment of anatase-phase TiO2 prepared by a hydrothermal method was performed under H2/N2 mixed atmosphere. The experimental results demonstrate that roasting TiO2 in a H2/N2 atmosphere can effectively reduce partial Ti4+ to Ti3+, thereby facilitating the production of tunable oxygen vacancies (OVs) by disrupting Ti-O-Ti bonds. OVs can construct defective energy levels to bring about a decrease in the bandgap of TiO2 and an extension of light absorption range. Moreover, OVs remarkedly improve the separation of photoinduced charges of TiO2 and accelerate the photocatalytic reaction as active sites. The photocatalytic experimental results demonstrate that TiO2 exhibits the highest performance when roasting TiO2 in a H2/N2 atmosphere for 2 h, and the photocatalytic degradation rate constant of rhodamine B (RhB) and tetracycline (TC) on this sample under simulated solar light irradiation is 2.24 and 1.11 times higher than that on the reference TiO2, respectively. These findings provide valuable insights for designing highly efficient photocatalysts for effective water pollution treatment.

Utilization of Biodiesel Residue through Efficient Microwave-Assisted Synthesis of Carbon Quantum Dots: A Versatile Nanomaterial for Environmental Remediation

The rapid expansion of the biodiesel industry has substantially increased crude glycerol residue (CG) production, creating sustainability and economic challenges due to surplus glycerol generation. Conventional purification methods are costly and environmentally demanding, necessitating innovative strategies to utilize this residue effectively. This study innovates by exploring the microwave-assisted synthesis of carbon dots (CDs) from CG, exemplifying a shift toward sustainable biodiesel production by transforming the residue into a multifunctional material. CDs exhibited a nanometric spherical morphology of 2.6 ± 0.3 nm diameter verified by HRTEM analysis. The reduction of oxygen confirmed the transformation of CG into CDs–H bands and the formation of polyaromatic structures. The graphitic structures were verified by Raman spectroscopy, electron paramagnetic resonance, and X-ray diffraction. The quantum yield (QY) was calculated to be 1.3%. The multifunctionality of CDs has been proven in sensing and photocatalysis. In the sensor applications, the CDs demonstrated strong fluorescence quenching in the presence of Fe3+ and Cu2+ ions, with a limit of detection of 1.8 ± 0.01 and 4.0 ± 0.04 mg.L-1, respectively, indicating the potential use of CDs in detecting these ions in wastewater samples. When complexed with titanium dioxide (TiO2), the TiO2/CDs composite showed an extended photoresponse of TiO2 to the UV-visible region, improving the efficiency of photocatalytic reactions for Victoria Blue B (VBB) dye degradation (98% degradation after 150 min). This research highlights the potential of utilizing CG to produce versatile CDs, contribute to more sustainable biodiesel production, and offer promising applications in environmental sensing and photocatalysis.

Photocatalyst-free light-promoted carbohydrate synthesis and modification

Photoredox catalysis has recently emerged as a powerful approach for preparing oligosaccharides because it uses mild conditions, is compatible with partially or completely unprotected carbohydrate substrates, and exhibits impressive regio‐ and stereo‐selectivity and high functional group tolerance. However, most catalytic photoredox reactions require an external photocatalyst (organic dye or expensive transition-metal complex) to deliver key glycosyl radicals. Several photocatalyst-free photocatalytic reactions that avoid the use of expensive metal salts or organic-dye additives have received significant attention. In this review, we highlight the most recent developments in photocatalyst-free light-promoted carbohydrate synthesis and modification, which is expected to inspire broad interest in further innovations in the green synthesis of saccharides.

3D-Micro-Flower like [formula omitted] Nanoplate Solid Solution: A facile and rapid room-temperature synthesis with excellent photocatalytic decomposition of antibiotics in water

This research addresses the environmental threat posed by residual antibiotics in water and explores the potential of the photocatalytic process as an eco-friendly solution for antibiotic wastewater treatment. Here in, a series of BiOBr1−xClx nanoplate solid solutions with varied Br:Cl molar ratios were synthesized through a simple co-precipitation method. These solid solutions exhibited superior visible-light-driven photocatalytic activity compared to pristine BiOCl and BiOBr. Notably, the BiOBr0.25Cl0.75 sample demonstrated exceptional performance, achieving 89% and 99% degradation efficiency for ciprofloxacin (CIP) and tetracycline hydrochloride (TCH), respectively, within 20minutes under optimum conditions. The outstanding performance is attributed to factors such as a large specific surface area, suitable morphology and band gap, effective separation of photo-generated electron-hole pairs, and the presence of meso-size pores in the structure. Thermodynamic studies confirmed the exothermic and spontaneous nature of the photocatalytic reactions. The proposed degradation pathway of CIP and TCH, along with the photocatalytic mechanism, is elucidated. The solid solution, BiOBr1−xClx, exhibits facile recyclability, robust stability, and excellent adaptability to actual aquatic environments, establishing its potential as a promising eco-friendly photocatalyst for antibiotic pollution control.

Radiation driven synthesis of MnSe nanoparticles with dual luminescence and magnetic characteristics and its role in photocatalytic reactions

Many biomedical applications can greatly benefit from the combination of photoluminescence and magnetic properties of non-toxic manganese-based nanomaterials and thus, it demands for synthesizing such materials in an aqueous environment. The present work reports aqueous synthesis of starch-capped manganese selenide (MnSe) nanoparticles (NPs) through a steady-state gamma irradiation route under ambient pressure and room temperature. As radiolysis is considered as the cleanest method among available chemical approaches, we preferred to employ this technique and endeavored to establish optimal conditions of such synthesis. The as-produced MnSe nanocrystals demonstrated strong photoluminescence with a quantum yield of ca. 32% and co-existence of paramagnetic with antiferromagnetic behavior. To look into possible light-induced reactions with aromatic molecules, the effectiveness of synthesized particles on photo-induced degradation of dyes of similar structure was investigated. The proposed strategy may pave the way for synthesizing magneto-fluorescent nanoparticles in aqueous medium, which may find immense scope in nano-photonics and nano-biotechnology including biological assays, labelling and imaging.

Protodefluorinated Selectfluor® Aggregatively Activates Selectfluor® for Efficient Radical C(sp3)-H Fluorination Reactions.

Efficient fluorination reactions are key in the late-stage functionalization of complex molecules in medicinal chemistry, in upgrading chemical feedstocks, and in materials science. Radical C(sp3)-H fluorinations using Selectfluor® - one of the most popular fluorination agents - allow to directly engage unactivated precursors under mild photochemical or thermal catalytic conditions. However, H-TEDA(BF4)2 to date is overlooked and discarded as waste, despite comprising 95% of the molecular weight of Selectfluor®. We demonstrate that the addition of H-TEDA(BF4)2 at the start of fluorination reactions markedly promotes their rates and accesses higher overall yields of fluorinated products (~3.3 × higher on average across the cases studied) than unpromoted reactions. Several case studies showcase generality of the promotor, for photochemical, photocatalytic and thermal radical fluorination reactions. Detailed mechanistic investigations reveal the key importance of aggregation changes in Selectfluor® and H-TEDA(BF4)2 to fill gaps of understanding in how radical C(sp3)-H fluorination reactions work. This study exemplifies an overlooked reaction waste product being upcycled for a useful application.

Next‐Generation Time‐Resolved Electron Paramagnetic Resonance for Direct Visualizing Mechanisms in Radical Chemistry

AbstractRadical chemistry is an important research field that plays a vital role in life science, material science, and energy conversions. However, directly visualizing the transient open‐shell intermediates unambiguously in radical chemistry is a significant and long‐standing challenge. Recently, we have developed an innovative ultrawide single‐sideband phase‐sensitive detection (U‐PSD) time‐resolved electron paramagnetic resonance (TREPR) technique, which enables the characterization of diverse transient radical intermediates and mechanistic studies close to reaction conditions. In this brief review, we will offer an outline of the principles underlying our U‐PSD TREPR technique, and present examples highlighting the technique's ability to accurately characterize and track free radical intermediates in photocatalytic reactions.

Recent Progress on the Synthesis, Biological Activity of Fused Pyrimidines from Azole Amines

AbstractFused pyrimidines are a class of heterocyclic compounds that have gained considerable interest due to their extensive biological activities and potential applications in drug development. This review article aims to provide a comprehensive overview of the latest synthetic approaches to fused pyrimidines, including Michael reactions, multicomponent reactions, metal‐catalyzed reactions, photocatalytic reactions, peroxide‐mediated reactions, and inverse electron demand Diels–Alder reactions. Furthermore, the biological activities of these compounds, such as their ability to combat cancer and microbial infections, are also discussed. This review article summarizes the existing literature on the synthesis and biological activity of fused pyrimidines from 2020 to 2023. We hope this review article will inspire the development of more effective and less toxic fused pyrimidine drugs with well‐designed structures.

Graphitic Carbon Nitride Based Semiconductors and Their Applications in the Field of Photocatalysis

An increasing number of advanced semiconductor materials have been reported with the progress of theoretical and practical researches. The graphitic carbon nitride (g-C3N4) stands out as a highly promising semiconductor photocatalyst. It is known for its visible-light reaction and good chemical stability, indicating its potential for extensive use in photocatalysis. Recently, rapid progress has been made in researching g-C3N4-based semiconductor substances in photocatalysis. Till now, a large amount of work has focused on the applications of g-C3N4 in photocatalysis. This work focuses on those researches concerning with g-C3N4-based photocatalytic substances. Their structural characteristics, synthesis techniques, and efficiency enhancement are discussed in detail. Besides, their applications in different photocatalytic reactions are also highlighted. These reactions include hydrogen production by water decomposition, degradation of organic matter, carbon dioxide reduction, and photocatalytic bactericide. This article also points out the problems and challenges in the photocatalytic performance. Meanwhile, the stability of g-C3N4 is also highlighted. It also puts forward the promising research directions of g-C3N4 in the field of photocatalysis.