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Graphitic carbon nitride (gCN) has shown great potential in photocatalysis. Developing suitable cocatalysts is a critical way to enhance gCN's photocatalytic performance. In this paper cobalt–nickel bimetallic phosphide (CoNiP) was used as a cocatalyst to modify gCN. A gCN/CoNiP composite was successfully prepared by a simple hydrothermal method. XRD, XPS, SEM, UV-vis DRS, and PL characterization studies showed that a Schottky junction-like structure was constructed between gCN and CoNiP, which intensified the visible light response, enhanced the charge transfer rate and prohibited the recombination of photogenerated carriers, thus significantly improving gCN photocatalytic activity. Under simulated sunlight, the removal efficiency of methylene blue (10 mg L−1) was 97.8% by 120 min of irradiation, 44.6% higher than that of gCN. The quenching experiment showed that ˙O2−, ˙OH and h+ were the main active species. Based on the above points, the possible mechanism of photocatalysis was deduced. [ABSTRACT FROM AUTHOR]

In this paper, a NiAl-LDH with the characteristic structure of a hydrotalc-like compound was applied as a carrier in a two-step hydrothermal process, and a MnCdS/In2S3/NiAl-LDH composite material was successfully prepared by loading MnCdS and In2S3 on the flower spherical-like surface of NiAl-LDH. The combination of NiAl-LDH with In2S3 and MnCdS made the band gap smaller and the light absorption range larger, thus increasing the utilization rate of light. 50% MnCdS/In2S3/NiAl-LDH composites had the best photoinduced charge separation and highest surface enrichment of photogenerated electrons. In the degradation experiment of crystal violet (CV), 50% MnCdS/In2S3/NiAl-LDH composites showed superior photocatalytic degradation efficiency (>98.5%) under full spectrum light. Furthermore, the applicability and universality of photocatalysts were studied by observing the degradation of CV by MnCdS/In2S3/NiAl-LDH composites under different conditions. In addition, the composites showed excellent hydrogen production capacity in the photolysis of water, in which hydrogen production within 8 hours was about 7661.51 μmol g−1. By combining the results of active species capture experiments, density functional theory (DFT) calculations and photoelectrochemical experiments, the possible mechanism of double S-scheme heterojunction photocatalysis among NiAl-LDH, In2S3 and MnCdS was inferred, which is one of the main reasons for the enhancement of photocatalytic activity. [ABSTRACT FROM AUTHOR]

The widespread use of antibiotics leads to the pollution of the water environment. Photocatalytic technology is considered as an effective way of removing antibiotics from the water environment. In this paper, a semi-embedded CdS/tubular g-C3N4 (CdS/TCN) heterojunction photocatalyst was designed and prepared by hydrothermal, in situ oil bath and thermal polymerization methods. Then Ni nanoparticles were loaded onto the surface of CdS/TCN by an in situ photoreduction method to form high performance photocatalyst Ni–CdS/TCN. The degradation rate of tetracycline hydrochloride (TCH) by Ni–CdS/TCN-6 was about 1.9 times higher than that of bulk carbon nitride (BCN) under visible light irradiation for 30 min. The high specific surface area, the effective heterojunction and loaded Ni broaden the light absorption range, narrow the band gap and improve the photogenerated carrier separation efficiency and migration rate. Beyond that, loaded Ni also inhibits photocorrosion and improves the stability of the photocatalyst. The present work provides a new way for designing a semi-embedded heterojunction photocatalyst. [ABSTRACT FROM AUTHOR]

In this paper, three-dimensional TiO2 nanoflowers (NFs) were prepared by a facile hydrothermal method, and Ag3PO4 was grown in situ following alkali treatment to design and synthesize a Ag3PO4/OH/TiO2 catalyst with excellent photocatalytic activity under visible light. The test results show that the photocatalytic degradation performance of TiO2 NFs after alkali treatment and Ag3PO4 loading is significantly improved. This is because the alkali treatment and the introduction of Ag3PO4 can provide a large amount of –OH, which can be converted to ˙OH under UV irradiation, followed by an increase in the number of active radicals to enhance the photocatalytic degradation performance. Meanwhile, the introduction of Ag3PO4 can effectively improve the light absorption ability of the photocatalyst. Moreover, the in situ growth of Ag3PO4 on TiO2 NFs can construct a high-quality Ag3PO4/TiO2 heterojunction to promote the charge separation and transport. Therefore, the degradation rate of Ag3PO4/OH/TiO2 can reach 90% after 30 min for degrading 3 mg L−1 RhB under visible light. The Ag3PO4/OH/TiO2 photocatalyst designed in the present work provides a new tool for the degradation of organic dyes. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysis is a potential solution to meet energy needs with green and inexhaustible solar energy. However, designing efficient and stable photocatalysts is a challenging task due to the limited ability to effectively separate electrons and holes. In this paper, by using a straightforward ethanol dispersion technique, we were able to combine ultrathin layered Cu-TCPP MOFs with g-C3N4 nanosheets, resulting in the creation of an extremely effective nano-composite photocatalyst with exceptional UV-vis activity. CT/CN heterojunctions displayed remarkable photocatalytic efficacy for the production of H2, with 3CT/CN showcasing a five-fold enhancement in photoactivity as compared to the unadorned g-C3N4. Based on the results of photoluminescence spectroscopy, electrochemical impedance spectroscopy, and electrochemical reduction, the considerably improved charge transfer and separation, together with the possible catalytic capability of uniformly distributed metal nodes in Cu-TCPP, are believed to be the underlying reason for the observed exceptional photoactivity. After thorough analysis, a potential process for charge transfer and segregation between g-C3N4 and Cu-TCPP has been suggested. [ABSTRACT FROM AUTHOR]

BiVO4, as a visible light catalyst, produces photogenerated electrons and photogenerated holes that are easy to recombine. In this paper, a BiVO4/Ag2O composite was prepared to promote the separation of photogenerated carriers of BiVO4. Compared with BiVO4, the properties and photocatalytic activity of BiVO4/Ag2O were obviously improved. The improvement of BiVO4/Ag2O was reflected in the better separation of photogenerated electrons and photogenerated holes, higher UV-visible maximum absorption wavelength, and stronger ability to degrade doxycycline. The effects of Ag2O on the crystal structure, the morphology and the binding energy of BiVO4 were analyzed by XRD, XPS and SEM, and the existence of a heterojunction in BiVO4/Ag2O was confirmed. The results of capture experiments showed that the photocatalytic processes of BiVO4 and BiVO4/Ag2O produced hydroxyl radicals (˙OH), holes (h+) and superoxide radicals (˙O2−). However, the contribution of active species was different in the two systems. The degradation pathways and intermediate products of doxycycline were analyzed by UPLC-QTOF. This work proposed a new method for the preparation of BiVO4/Ag2O particles with remarkable photocatalytic activity, and provided a reference for the degradation of doxycycline. [ABSTRACT FROM AUTHOR]

In this paper, NiCo2S4 was coated on the surface of WS2 of a 1T/2H mixed phase by a two-step hydrothermal method to form an in situ core–shell structure. The unique S-scheme heterojunction of the NiCo2S4@WS2 core–shell composite photocatalyst improved the easy recombination of carriers caused by the narrow band gap of NiCo2S4 and WS2, and improved the photocatalytic hydrogen production performance. The loading ratio of NiCo2S4@WS2, the addition of Eosin Y, and the pH value of TEOA were optimized. Under the optimal conditions, the hydrogen production rate reached 5.814 mmol g−1 h−1, which is about 8.55 times and 3.35 times the hydrogen evolution rates of NiCo2S4 and WS2, respectively. The composite catalyst exhibits excellent charge separation efficiency in photoelectrochemistry, PL and BET tests, carrier transport rate and large specific surface area that can provide more active sites, which are the main factors for the improvement of the hydrogen evolution performance. This paper demonstrates new design strategies to drive efficient photocatalytic hydrogen production by building in situ core–shell structures and optimizing the carrier transport paths, which will yield new insights. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysts have been widely investigated in the field of selective organic transformation. However, the practical application of photocatalysts is greatly limited due to their low charge separation efficiency. Recently, electron–hole separation using intrinsic electric field of polar semiconductors has attracted much attention. Polarity exists widely in polar noncentrosymmetric (NCS) materials, such as piezoelectric, pyroelectric and ferroelectric materials. In the crystal structure of NCS materials, the asymmetric arrangement of ions or ion groups leads to the distribution of positive and negative charges on the surface in opposite directions, which could effectively separate the electron–hole pairs. This perspective summarized recent progress in the synthesis and photocatalytic application of polar semiconductors for selective organic synthesis. This paper also briefly introduces the working mechanism of a light free or vibration catalyst (piezoelectric catalyst). Generally, this perspective mainly focuses on five kinds of polar semiconductors, including CdS, ZnO, ABO3, bismuth layered materials and two-dimensional polar materials. The challenges encountered, as well as the current and future scopes of this field are also discussed in this perspective. [ABSTRACT FROM AUTHOR]

In this paper, a series of BN/NTCDA photocatalysts have been prepared using a simple calcination method and their photocatalytic performance under visible light irradiation is studied with tetracycline (TC) as the target pollutant. When the ratio of BN and NTCDA is 100 : 1 and the temperature is 350 °C, the sample (BN/NTCDA (100 : 1)) has the highest adsorption efficiency (28.65%) and photodegradation efficiency (51.54%) for TC. The characterization results of XRD, FTIR, XPS, TEM, and 1H NMR show that BN/NTCDA (100 : 1) is a BN-based photocatalytic material, which is likely formed through the reaction of the surface hydroxyl group of BN and the anhydride of NTCDA. The band gap of BN is about 4.11 eV, and the band gap of NTCDA is 2.67 eV. So, the electron is firstly excited from the VB of NTCDA to its CB, and then the electron in the VB of BN is excited into the empty VB of NTCDA, implying that TC is degraded by photoactive species (˙O2−, h+ and ˙OH) from the VB of BN and CB of NTCDA. The capture experiment of photoactive species suggests that ˙O2− makes the main contribution to TC photodegradation, followed by h+, ˙OH. After five recycle experiments, BN/NTCDA (100 : 1) still has 77.32% removal efficiency for TC. The removal efficiency (80.19%) of BN/NTCDA (100 : 1) is higher than that of TiO2 (75.63%) and g-C3N4 (24.44%). This work contributes to the development of novel metal-free-photocatalysts and the application of photocatalytic technology to the removal of antibiotics. [ABSTRACT FROM AUTHOR]

Low efficiency of photogenerated electron–hole separation has been a challenge for organic conjugated polymer photocatalysts. Our preceding studies have revealed that polymers containing B←N coordination bonds can form a localized built-in electric field that effectively promotes photogenerated charge separation. However, B←N coordination units are still scarce and require more examples to find regularities in their structural design. The systematic development and testing of B←N coordination units is necessary for the efficient development of subsequent polymers containing B←N coordination bonds. In this work, three conjugated polymers containing B←N coordination bonds, PBN–Ni, PBP–Ni, and PBS–Ni, were synthesized by changing the substituents of the boron atoms and introducing narrow-band thiophene units to form conjugate and energy band gradients. The energy band modulation and localized built-in electric field construction were both achieved as planned, while the bandgap and photogenerated charge transport capabilities caused performance discrepancies. The experimental results showed that PBN–Ni had a better photocatalytic hydrogen evolution (HER) performance, reaching 104.6 μmol h−1 (λ > 420 nm). The optimal optical absorption edge of PBS–Ni was up to 643 nm, but the HER was lower, at 33.2 μmol h−1 (λ > 420 nm, 1% Pt). PBP–Ni optimized some of the optical absorption efficiencies (511 nm) while ensuring the HER activity (96.6 μmol h−1, λ > 420 nm). This work tentatively explores the characterization of the B←N coordination bond-containing base units serving as photocatalysts and provides the basic model experience and data reference for the subsequent expansion of B←N coordination bond-containing units and the development of B←N coordination bond-containing copolymer systems. [ABSTRACT FROM AUTHOR]

Visible-light active heterogeneous photocatalysts offer various advantages owing to their ability to exploit clean, renewable, and economically viable visible light as a driving force. This study aims to develop such photocatalysts by incorporating various loadings (10, 20, and 30 wt%) of bismuth tungstate (Bi2WO6 or BWO) into graphitic carbon nitride (g-C3N4 or CN) nanosheets. The CN nanosheets and BWO nanomaterials are synthesized using an eco-friendly hydrothermal method. The objective is to evaluate the photocatalytic activity of these catalysts for the Knoevenagel condensation reaction under 12 W blue LED light (low power), aiming to outperform the activity of pure CN. Various characterization methods, including XRD, UV-vis DRS, FTIR, PL, XPS, and TEM, are employed to analyze the catalysts. The study specifically focuses on the performance of the various BWO loading percentages on CN nanosheets. Among those, 20 wt% BWO loaded CN achieves a yield of 80% with minimal activity decline over five recyclability cycles. Furthermore, this study identifies that BWO/CN follows a Z-scheme pathway, enhancing the photocatalytic performance and facilitating organic transformations. Scavenging experiments confirm the formation of radicals during photocatalysis, validating the proposed mechanism and providing crucial mechanistic insights. Ultimately, this research seeks to highlight BWO/CN as a promising, environmentally friendly photoactive substance with significant potential for effective photocatalytic use. To our knowledge, this is the first study to use BWO/CN catalysts for the Knoevenagel condensation reaction under blue LED irradiation. [ABSTRACT FROM AUTHOR]

We present photophysical studies on homoleptic zinc-dipyrrin complexes representing intramolecular donor–acceptor systems. Intramolecular charge transfer depends on ligand variation and intermolecular environmental influences. In particular, we focus on steady-state and transient absorption methods to compare the response of the ligand dynamics with that of the complexes after photoexcitation. For the first time, we successfully tested zinc bis(dipyrrinato) complexes as photocatalysts in two different aerobic photooxidation reactions. Early-time dynamics after 100 fs in dichloromethane and in ethanol can be assigned to charge transfer states, while the subsequent response constitutes broad-band excited state dynamics, most likely of overlapping singlet and triplet states when probed in a relatively wide spectral window from 350 to 1400 nm and up to a delay time of 1.6 ns. In addition, a strong correlation between steady-state and time-resolved experiments makes this experimental approach a versatile tool for future investigations of this class of molecules, especially with respect to photocatalysis. The results of this study underpin the need for further development for quantifying amplitudes of the excited state population of electronically excited singlet and triplet states. [ABSTRACT FROM AUTHOR]

This method describes the iron-promoted amidation of dioxazolone under visible light to obtain aromatic/alkyl substituted amides. The nitrogen radicals formed during this process undergo hydrogen atom transfer (HAT) to form amides through the proton provided by HBpin. This reaction eliminates the need for external chemical oxidants and expensive photocatalysts, and exhibits compatibility with various aryl/alkyl substituted derivatives. This method has good prospects for application and development in organic synthesis and medicine. [ABSTRACT FROM AUTHOR]

The construction of heterojunctions is an effective strategy to improve the photogenerated carrier mobility rate and enhance the photocatalytic performance. The main bottlenecks in developing semiconductor photocatalysts lie in the poor light absorption and the fast recombination of photogenerated electron–hole pairs. In order to enhance the photocatalytic conversion of CO2, in this work, a kind of 2D/2D CuS/Ti3C2 heterostructure nanocomposites were designed. The formation of the heterojunction structure resulted in a significant enhancement of the light absorption range in the visible region of pristine Ti3C2 and a slight increase in the semiconductor bandgap width (2.58 eV), which in turn increased the generation of photogenerated electron–hole pairs and facilitated the acceleration of the carrier mobility efficiency, leading to a substantial improvement of the photocatalytic activity. After controlling the molar ratio of CuS/Ti3C2 at the optimum value of 1 : 8, the photocatalytic CO2 reduction conversion rate was the highest in the absence of co-catalysts. The yields of CO and CH4 were 10.68 and 25.21 μmol g−1 h−1, respectively, and were 5.51 and 3.15 times higher than that of pristine Ti3C2. Moreover, it resolved the bottleneck of the single CuS reduction product being only CO. In addition, the CuS/Ti3C2 (1 : 8) photocatalyst exhibited 35.07% selectivity and a C2H4 yield of 10.05 μmol g−1 h−1. The presence of large amounts of C1 and C2 intermediates on the catalyst surface was observed by in situ FTIR. Notably, after a cycling stability test lasting 40 h, the best samples retained 88.8% of the initial efficiency with good stability. This study further elucidates the mechanism of action and synergistic effects of CuS and Ti3C2 semiconductors in enhancing photoactivity. [ABSTRACT FROM AUTHOR]

The development of stable and durable oil/water separation materials with photocatalytic activity holds great significance for the purification of complex oily wastewater containing refractory organic pollutants. Herein, a multifunctional Ag@Cu2O decorated copper mesh was designed and prepared via a two-step hydrothermal method. The material possesses outstanding superwettability, photocatalytic activity, and antibacterial properties towards Escherichia coli and Staphylococcus aureus. The mesh demonstrates remarkable and durable superhydrophilic properties while maintaining underwater superoleophobic characteristics, enabling excellent separation efficiency and high permeability flux involving various oil/water mixtures in gravity-driven separation processes. Under visible light, the Ag@Cu2O anchored mesh serves as an effective photocatalyst in the removal of dyes and tetracycline antibiotics from aqueous solution. The catalyst shows high stability and reusability and exhibits high performance after 5 cycles of photocatalytic tests. Density functional theory calculations reveal that the improved photocatalytic performance is attributed to the narrowed indirect band gap after Ag anchoring. The silver atoms induce the shifting up of the energy level of the Cu 3d orbital, enhancing the photocatalytic activity of Cu2O. The outstanding performance of the Ag@Cu2O anchored mesh endows this material with great application potential in the removal of refractory pollutants from oily wastewater. [ABSTRACT FROM AUTHOR]

In this work, based on the electrostatic adsorption theory, a direct Z-scheme NH2-UiO-66/BiOCl composite photocatalyst was prepared by a one-step solvothermal method with NH2-UiO-66 embedded on the smooth surface of flower-like BiOCl without additional chlorine source to form a close contact interface. The photocatalytic degradation of tetracycline hydrochloride (TCH) of 1.0-NH2-UiO-66/BiOCl(1.0-NUBC) prepared under simulated sunlight was 1.63 times and 78.84 times that of pure BiOCl and pure NH2-UiO-66, respectively. The reason for the enhanced photocatalytic performance may be that electrostatic adsorption promotes the homogeneous and orderly synthesis of heterogeneous structures, significantly increasing the ratio of NH2-UiO-66/BiOCl surface, which not only improves the visible light response range but also promotes the formation of the interface electric field between NH2-UiO-66 and BiOCl interface. The separation and transfer of the photogenerated electron–hole pairs are greatly promoted. Therefore, this study provides an effective way for the synthesis of BiOCl/MOF composites and has a good application prospect. [ABSTRACT FROM AUTHOR]

Bi5O7I doped with Zn2+ (Zn2+/Bi5O7I) was prepared using a precipitation calcination method. Its photocatalytic activity was improved by adjusting the band gap of Bi5O7I, and its photocatalytic performance was evaluated by degrading RhB. The experimental results showed that Zn2+/Bi5O7I-8 had the highest photodegradation efficiency, and the degradation rate for RhB after exposure to light for 30 minutes was 91% and reached 100% in 60 minutes. The degradation rate constant k of Zn2+/Bi5O7I-8 reached 0.10813 min−1, which is 13 times more than that of Bi5O7I. As a result of Zn2+ being added into Bi5O7I, the band gap of Zn2+/Bi5O7I became narrower than that of Bi5O7I, and the photogenerated electrons and holes were successfully prevented from recombining; therefore, the photocatalytic activity of Zn2+/Bi5O7I was higher than that of Bi5O7I. After four rounds of photocatalytic experiments, the photocatalytic efficiency of Zn2+/Bi5O7I-8 remained high. The composition and microstructure of the materials were characterized using XRD, FTIR, XPS, SEM, and TEM. The optical properties and degradation mechanism of the material were investigated using DRS, PL, photocurrent response, and active substance capture experiments. A suggested mechanism for the photocatalytic degradation of RhB is presented. [ABSTRACT FROM AUTHOR]

Carbon dioxide reduction together with aerobic oxidative cyclization using eosin Y-based light-harvesting photocatalysts remains a key challenge. In this study, we present the first-ever synthesis of unique in situ Se-infused eosin Y (Sein–EY) flexible photocatalysts through a simple one-pot method. The as-synthesized Sein–EY flexible film photocatalyst exhibits outstanding performance for the production of formic acid (204 μM in 2 h) and aerobic oxidative cyclization of thioamides via the formation of C–N/C–S bonds with outstanding yields (98.6%) when exposed to solar light. The presence of infused Se significantly extends the solar light absorption capacity of the Sein–EY photocatalyst, reaching up to 580 nm. This study opens up a new pathway for the rational design and synthesis of potentially effective Se-infused-EY photocatalysts through a simple and scalable method, enabling both solar chemical production and efficient one-pot three-component reactions. [ABSTRACT FROM AUTHOR]

In this work, CoV-LDH/ZnIn2S4 (CoV-LDH/ZIS) nanocomposites were synthesized through a self-assembly process in order to investigate the influence of CoV-LDH addition on the rate of hydrogen production. XRD and TEM measurements confirmed the effective preparation of CoV-LDH/ZIS nanocomposites. Among all the nanocomposite photocatalysts, 2.0%-CoV-LDH/ZIS showed the best photocatalytic performance with a hydrogen production rate of 1397.3 μmol g−1 h−1, approximately 2.2 times that of pure ZnIn2S4 (ZIS). The X-ray photoelectron spectroscopy (XPS) measurement indicated that there is a strong interfacial interaction between ZIS and CoV-LDH, indicating that more than simple mechanical mixing had occurred. The steady-state fluorescence spectroscopy (PL) and time-resolved photoluminescence (TRPL) spectroscopy results showed that the electron and hole recombination in CoV-LDH/ZIS is significantly reduced and that efficient interface charge transfer and separation are achieved. This work sheds light on the interfacial electron transfer between two semiconductor materials, which promotes the separation of photogenerated carriers and thus enhances photocatalytic hydrogen production activity. [ABSTRACT FROM AUTHOR]

The development of high-efficiency photocatalytic materials responsive to visible light is one of the most effective ways to address the environmental threats posed by organic dyes in industrial wastewater. In this paper, novel visible-light-responsive nitrogen–sulfur co-doped carbon quantum dots modified ZnO (ZnO/N,S-CQDs) composites with a significantly enhanced photocatalytic degradation performance of Rhodamine B (RhB) were successfully synthesized. Under visible light, the photocatalytic degradation efficiency reached 98.7% over the optimal composite. Besides, the degradation obeyed the pseudo-first-order kinetics model with a photocatalytic rate constant (k) of 0.0473 min−1, which was around 3.71 times higher than that of pure ZnO nanoparticles (0.01273 min−1). In addition, the morphology, size and elemental composition of the ZnO/N,S-CQDs were characterized using TEM, SEM, XRD, FT-IR, and XPS which confirmed the successful synthesis of the composites. Photoluminescence (PL) and transient photocurrent response results indicated an increase in the carrier separation efficiency of ZnO/N,S-CQDs. Based on the active species removal experiment, superoxide radicals (˙O2−) played a leading role in the photocatalytic reactions and a possible photocatalytic degradation mechanism was revealed. These further demonstrate that the N,S-CQDs with varying properties contributed significantly to the enhanced photocatalytic activity of ZnO. Overall, the present method follows the principle of green economy, and novel N,S-CQDs provide a feasible approach for the development of photocatalytic performance of ZnO. [ABSTRACT FROM AUTHOR]

Finding efficient photocatalysts is the key to achieving sustainable hydrogen production. In this work, a rational design of Cd2+-doped Zn3In2S6 (ZIS) and a heterojunction structure with g-C3N4 (GCN) was carried out to form a GCN/Cd/ZIS composite. The synergistic effect of Cd2+ doping and heterojunction construction in the photocatalytic hydrogen production process was probed. The results showed that doping Cd2+ modified the bandgap structure of ZIS and improved the photocatalytic activity. The heterojunction construction between Cd/ZIS and GCN also effectively promoted the separation and migration of photogenerated carriers, which significantly improved the hydrogen production performance of the GCN/Cd/ZIS composite. The hydrogen production rate of 15% Cd/ZIS and 5% GCN/Cd/ZIS was 2.45 mmol g−1 h−1, 3.34 mmol g−1 h−1, which was 4.3 and 5.9 times higher than that of ZIS (0.57 mmol g−1 h−1), respectively. This study provides strong evidence that doping and heterojunction construction can synergistically improve photocatalytic activity. [ABSTRACT FROM AUTHOR]

Advanced oxidative process is an efficient method to photocatalytically degrade the effluent pollution by organic dyes with a suitable catalyst. Photocatalysts with a heterojunction not only improve the excitation efficiency of the catalyst in the presence of light by broadening the wavelength range of absorption but also reduce the rate of recombination. ZnO and TiO2 were successfully synthesized in this study via solution combustion synthesis. Wurtzite ZnO was grown along with anatase TiO2 to create a heterojunction of ZnO–TiO2, and Co loading was carried out to improve the rate of electron transfer between the heterojunction for enhanced photocatalytic activity. The photogenerated electrons are injected from the conduction band of ZnO to TiO2via Co to create ˙O2− and holes from TiO2 to form OH˙, which help to degrade alizarin S. The detailed photocatalytic experiment confirmed Co/ZnO–TiO2 as an extremely efficient catalyst, which shows the complete degradation of the dye alizarin S in just 40 minutes under UV light illumination. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production has garnered considerable attention as a latent solution to various energy challenges. Because of their distinct optical characteristics, persistent luminescence nanoparticles (PLNPs) can emit light long after illumination ends, making them highly advantageous for round-the-clock photocatalysis. However, photocatalytic activity is currently restricted owing to the low specific surface area and the high number of photogenerated electron–hole pairs. In this study, PLNP (ZnGa5Si5O18)/sulfur-doped carbon nitride (SCN) was synthesized via a solvothermal method and calcination. Under irradiation with a xenon lamp, the resulting PLNPs/SCN (1 : 1) composite exhibited excellent photocatalytic hydrogen evolution activity, with a hydrogen evolution rate of 3963.80 μmol g−1 h−1, which was 15 times and 1.4 times higher than that of PLNPs (307.1 μmol g−1 h−1) and SCN (2800.80 μmol g−1 h−1), respectively. The formation of a stable type II heterojunction is responsible for the high photocatalytic activity. This heterojunction effectively suppressed the electron–hole complexation generated during photoexcitation and enhanced the carrier flexibility. In addition, the PLNPs/SCN (1 : 1) composite had a larger specific surface area than the PLNPs. The synthesis of this novel composite heterojunction under mild conditions not only provides a new strategy for preparing PLNP-based composite catalysts but also holds significant potential for enabling round-the-clock photocatalysis. [ABSTRACT FROM AUTHOR]

It is essential to design and fabricate semiconductor-based photocatalysts with excellent activity to split H2O into H2 and O2 using sunlight because of the depletion of fossil resources and environmental pollution. LaVO4 is a visible light catalyst with a narrow band gap, satisfactory stability, and a low price. Therefore, in this work, alkali metal-doped LaVO4 was manufactured. Alkali metal-modified LaVO4 was prepared by a hydrothermal method as a photocatalyst for water splitting under visible light illumination, and a series of characterizations was carried out. The results showed that alkali metal doping improved the catalytic performance of pure LaVO4 and mainly optimized the hydrogen and oxygen production of Na-doped LaVO4 so that a maximum H2 and O2 evolution of 2.83 and 0.71 mmol g-1 h-1, respectively was obtained. The superior photocatalytic activity of Na-doped LaVO4 was mainly attributed to synergistic effects, including the extended visible-light response and improved charge separation. This study provides a new idea for the design of a highly efficient LaVO4-based water-cracking photocatalys.t. [ABSTRACT FROM AUTHOR]

A novel MIL-101(Fe)/ZnCrZr-LBMO heterojunction was successfully constructed and used for the removal of ciprofloxacin (CIP) in this work. The MIL-101(Fe)/ZnCrZr-LBMO composite exhibited significantly enhanced photocatalytic degradation activity, with reaction rates approximately 3.4 and 3.1 times faster than those observed with pristine MIL-101(Fe) and ZnCrZr-LBMO, respectively. The effect of different amounts of ZnCrZr-LBMO, sample pH, CIP concentration, inorganic cations, and anions on CIP removal was investigated, and the possible intermediates and degradation pathways of CIP were speculated. The·O2− radicals dominated CIP degradation, with minor contributions from 1O2, h+, and ·OH radicals. The composite exhibited high removal rates for CIP (94.7%), ofloxacin (86.8%), and tetracycline (96.3%), respectively, within 60 min of light irradiation, and excellent reusability, retaining over 85.1% CIP degradation rate after five cycles. Our work provides a new reference to construct highly efficient and easily recyclable MIL-101(Fe)/ZnCrZr-LBMO photocatalysts for the removal of antibiotic pollutants, promising advancements in real water treatment applications. [ABSTRACT FROM AUTHOR]

Photocatalytic degradation of pollutants is one of the most promising strategies for addressing environmental issues associated with wastewater from textile and other dyeing industries. Graphitic carbon nitride (g-C3N4) has emerged as a prospective visible-light photocatalyst in this field due to its various advantages. However, pristine g-C3N4 often exhibits limited activity. To enhance the performance of g-C3N4, alkali metal ion doped g-C3N4 was prepared using a simple one-step thermopolymerization method. Characterization and analysis of the samples revealed that the obtained doped photocatalysts exhibited enhanced visible-light photocatalytic degradation activity. This is attributed to the reduction in grain size, which provides more active sites, extended visible-light absorption, a reduced bandgap, and more efficient electron transfer. Notably, due to the optimal adjustment of the microstructure and electronic structure, K+ doped g-C3N4 demonstrated the highest photocatalytic performance with a degradation rate of 89.1%, significantly surpassing the efficiency of pristine g-C3N4 (72%). These results demonstrated that the approach of incorporating alkali metal ions into g-C3N4 has the potential for facilitating high-performance photodegradation for organic pollutant removal. [ABSTRACT FROM AUTHOR]

The most effective approach to develop new photocatalysts involves solar activation and prevention of the recombination of photogenerated hole–electron pairs. To achieve these goals, in this work, a series of bismuth oxyiodide and graphene oxide (BiOI/GO) composites were synthesized by a simple ex situ method. The structural, morphological, optical, and electrical properties of the synthesized compounds were thoroughly investigated. The photooxidation reaction of NO in the gas phase under visible light irradiation was used to assess the photocatalytic activity of BiOI/GO composites. The results showed that a small amount of GO significantly improved the photocatalytic activity. The BiOI/GO-0.5% sample prepared with 0.5 wt% GO showed the highest NO conversion (∼100%), indicating excellent photocatalytic stability after four continuous irradiation cycles and a high selectivity of 97% for nitrate ion formation. The increase in photocatalytic activity was mainly related to increased light absorption, high specific surface area, and better separation of light-generated charges. The use of chemical scavengers contributed to clarifying certain aspects of the possible photooxidation process of NO, which demonstrated that superoxide radicals (˙O2−) could be the main factor responsible for the photodegradation of NO by BiOI/GO-0.5%. [ABSTRACT FROM AUTHOR]

Due to the rapid progress of transition metal photocatalysis, developing novel and effective ruthenium photocatalysts and their corresponding heterogeneous counterparts is highly in demand. In this study, we first prepared tetraiodo-substituted 2,6-bis(1,2,3-triazol-4-yl)pyridine ruthenium(II), and further used this complex to construct 2,6-bis(1,2,3-triazol-4-yl)pyridine ruthenium(II) embedded porous organic polymers (POP-Ru). The as-prepared Ru(II) complex was employed as a photocatalyst, which showed higher photocatalytic activity than those of the commercial Ru(II) counterparts, but lower than that of the corresponding polymers. In particular, the polymer POP-Ru-1 has been disclosed to be highly efficient for the photosyntheses of thiocarbomates and disulfides, exhibiting a broad substrate scope. After simple separation workups, the photocatalyst could be recycled and reused for 10 times without obvious loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

TiO2/rGO (TG) composites were synthesized using a hydrothermal reduction method, with titanium dioxide and graphene as the starting materials. Subsequently, dye-sensitizing titanium dioxide/graphene photocatalytic composites, named DTG and APTG, were prepared by covalently attaching C.I. Direct Black 17 or C.I. Acid Violet 3 dye onto TG. The composites were characterized using FTIR, TEM, UV-vis DRS, EDS, and Raman spectroscopy. The EDS surface scanning results of APTG and D2.70TG composites have shown that Ti and S atoms are uniformly distributed on the graphene sheets. The presence of characteristic peaks for S2p and N1s near 166 eV and 399 eV in D2.70TG and APTG was intensified compared to those of TG composites. The grafting rate reached its peak when the amount of C.I. Direct Black 17 was 2.70 and the fixed amount of TG was 0.1 g. The UV-vis diffuse reflectance spectroscopy study results demonstrated a shift in the response range to visible light after dye modification for DTGs and APTG. Photocatalytic experiments showed that D2.70TG was capable of removing over 99% of MB within 1 hour. Furthermore, after 5 cycles of photocatalytic experiments, the removal rate of MB remained at above 95%. [ABSTRACT FROM AUTHOR]

Photocatalytic sterilization has been proven to be an effective strategy for eliminating pathogenic microorganisms, so the development of photocatalytic antibacterial hydrogel is considered to be essential for the treatment of skin wounds. Herein, a novel AgNPs/g-C3N4/PVA bactericidal hydrogel with excellent antibacterial activity towards Escherichia coli (E. coli) was successfully prepared via a cyclic freeze–thaw method. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), and other techniques were used to characterize the structure and morphology of the as-prepared bactericidal hydrogel. The mechanical properties of the bactericidal hydrogel including adhesion, tensile strength and antifatigue strength were evaluated. Full-thickness wound defect models were established to investigate its antibacterial activity. According to the bactericidal mechanism, the predominant active intermediate species are ˙OH and ˙O2−. In conclusion, the as-prepared AgNPs/g-C3N4/PVA hydrogel has good bactericidal activity and excellent mechanical properties, which could significantly promote wound healing. This work provides new insights for the preparation of photocatalytic antibacterial hydrogels. [ABSTRACT FROM AUTHOR]

Restricted light absorption spectra in conjunction with intrinsic material instability present formidable challenges to the effective functionality of existing photocatalytic systems. As a viable alternative to conventional photocatalytic materials, hydrogen-bonded organic frameworks (HOFs) can form conjugated systems through coupling and stacking effects, which can effectively promote the rapid transfer of charge over a wide optical range and improve the stability and photocatalytic activity. Herein we employ a large conjugate system material based on cobalt phthalocyanine (HOF-CoPcTc) as a proof of concept for this approach. The carboxyl groups in the tetracarboxy cobalt phthalocyanine were conjugated with phthalocyanine macrocycles which could extend the π-electron conjugation system of HOF-CoPcTc. Remarkably, the decomposition rate of the sulfamethoxazole (SMX) molecule in an aqueous solution was about 99% after 120 min under visible light irradiation for HOF-CoPcTc, which is a significant 9.78-fold improvement over that of the ligand CoPcTc. This study demonstrated that metal phthalocyanine compositions with carboxyl groups can be used to successfully synthesize HOF materials for large conjugated systems and provide a useful method for achieving efficient photocatalytic degradation of antibiotics. [ABSTRACT FROM AUTHOR]

A series of defective MnmIn2S3+m (m = 1–5, integer) microflowers were successfully synthesized via a facile hydrothermal method and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). These solid solution photocatalysts have similar cubic phase crystal structures. The results of electron paramagnetic resonance (EPR) spectra showed that the concentration of sulfur vacancy (VS) increased with the increase in Mn/In atomic ratio. The photocatalytic performance of the prepared MnmIn2S3+m was evaluated by the reduction of Cr(VI) in aqueous solution under simulated sunlight, in which Mn4In2S7 showed the highest photocatalytic activity. 40 ppm K2Cr2O7(VI) was almost completely reduced to Cr(III) within 60 minutes. Additionally, the photocatalytic mechanism was investigated and it was demonstrated that the appropriate concentration of VS could accelerate the carrier separation and transfer of Mn4In2S7, so as to improve the photocatalysis efficiency. This work will expand the application of solid solution photocatalysts in the future. [ABSTRACT FROM AUTHOR]

Multifarious novel photocatalysts based on hybrid nanocomposites have been developed to boost photocatalytic efficiency. However, the photocatalytic property of hybrid nanocomposites is still bound by inferior thermal stability, tardive charge motion kinetics and few active sites. In this work, a convenient and facile cation exchange approach was conceptually provided for fabricating a well-designed and robust P–N heterojunction based on Mn–Zn–S–ethylenediamine hybrid nanocomposite. Such hybrids take ZnS–ethylenediamine as the skeleton, and the Mn2+ cations are superseded and inserted into the interlayer of ZnS through the cation exchange approach, thus forming the Mn–Zn–S–ethylenediamine hybrid nanocomposite. Hence, as-synthesized ZnS–Mn1.0 had a significantly promoted photoactivity for reducing p-nitroaniline (94.5%) and p-nitrotoluene (88.6%) to the corresponding amino derivatives, besides oxidizing phenol (94.6%) under simulated solar irradiation. Meanwhile, PEC measurements illustrated that the interface created by this cation exchange approach was beneficial to promoting the motion behavior and prolonging the lifetime of photo-generated charges. Through this work we hope to offer an emerging strategy to finely design and fabricate all hybrid nanocomposite-based heterostructured photocatalysts for enhancing solar-to-chemical energy conversion. [ABSTRACT FROM AUTHOR]

The application of non-noble metal catalysts to photocatalytic hydrogen production from water holds a high practical application value. In this study, photocatalysts were obtained by the hydrothermal and photodeposition methods. The optimal photocatalytic hydrogen production from water decomposition was 2641 μmol g−1 h−1. The results showed that compared with traditional composites, a ZnCdS(Two-Step)/Ni photocatalyst synthesized with Prussian blue analogue (PBA) as the precursor shows better photocatalytic performance for hydrogen evolution. Moreover, the introduction of Ni is found to be a feasible strategy to modulate the performance of photocatalysts, providing a reference for the construction of materials with excellent photocatalytic properties. [ABSTRACT FROM AUTHOR]

Perovskite materials are emerging as the most promising and efficient low-cost energy materials for various applications. The construction of heterojunctions has become a field of interest because of their high potential to give off a large amount of energy. Herein, a Z-scheme heterojunction was made between two perovskites (CoTiO3 and CaTiO3) in order to make a cheap material that is good at photocatalysis. Various methods were used to characterize the resulting CoTiO3/CaTiO3 (CCO 75: 25) composite, including XRD, Raman, XPS, HRSEM, HRTEM, BET, and UV-vis. The increased photocatalytic activity of the CoTiO3/CaTiO3 (CCO) composite is attributed to the accelerated charge transfer from O2- to Ti4+ and from Co2+ to Ti4+ ions, revealing the close interfacial contact between CoTiO3 and CaTiO3, and spatial charge transfer within the CoTiO3/CaTiO3 heterojunction. A direct Z-scheme mechanism was developed, and charge transfer properties were verified by the scavenger test and ESR, PL, and EIS analyses. The enhanced degradation rate of k = 0.0373 min-1 is achieved for the CCO 75: 25 composite. Meanwhile, the CCO 75: 25 composite established high photocatalytic stability when recycled for CBZ degradation. This research offers mechanistic and practical views on designing simple and cost-effective materials for pollutant removal. [ABSTRACT FROM AUTHOR]

In this study, a series of Bi-ZnAl-LDHs (BZA-X) enriched with oxygen vacancies (OVs) were synthesized by doping ZnAl-LDHs with different ratios of bismuth ions. The characterization results indicated that the doping of bismuth ions promotes the formation of oxygen vacancies (OVs), with the highest level of oxygen vacancies when the bismuth ions are doped at 50%. The level of oxygen vacancies is lower than that of the conduction band, which leads to a substantial increase in the separation efficiency of photogenerated carriers from BZA-X. In addition, the oxygen vacancies in BZA-X promote the adsorption of H+ in the reaction system, which further promotes the formation of ˙OH. The main active species ˙OH and h+ contributed the most to the photodegradation of CIP, and the degradation rate and the degradation kinetic constant of ciprofloxacin (CIP) for BZA-0.5 were 1.56 and 2.63 times higher than those of ZA, respectively. On this basis, a CIP transformation pathway was proposed based on the identified transformation products. This work provides a new strategy to improve the degradation of ciprofloxacin in wastewater through the synergistic effect of bismuth-doped and oxygen vacancies. [ABSTRACT FROM AUTHOR]

In this research, composite photocatalysts were found to have a superior photocatalytic performance. A simple hydrolytic method is used to synthesize the BiPO4/Bi4O5I2 composite, and this was confirmed by use of characterization methods. The oilfield pollutant of acrylamide was used to evaluate the photocatalytic activity. After ultraviolet visible (UV-Vis) light irradiation for 6 h, the BiPO4/Bi4O5I2 displayed an excellent photocatalytic performance which was better than using Bi4O5I2 and BiPO4 singly. The characterization data further demonstrated the remarkable photocatalytic activity of BiPO4/Bi4O5I2. The trapping experiments and ESR experiments verified the photocatalytic mechanism. The recycling experiments used the degradation of Rhodamine B (RhB) to investigate the stability and reusability of BiPO4/Bi4O5I2. This paper details a new approach for the synthesis of a BiPO4/Bi4O5I2 composite, which exhibited efficient photocatalytic activity, for use in the degradation of oilfield pollutants. [ABSTRACT FROM AUTHOR]

Porphyrins have been widely used in designing photocatalyst systems. However, finding an effective strategy to improve the intrinsic photocatalytic activity of porphyrin molecules remains a challenge. Here, two new porphyrins, meso-tetra(5-carboxyfuryl)porphyrin (H2TCFP) and meso-tetra(5-carboxythienyl)porphyrin (H2TCTP), were successfully synthesized and compared with meso-tetra(m-carboxyphenyl)porphyrin (H2TmCPP), to clarify the influence of the organic unit bridging the carboxyl acid group with the porphine ring on the photocatalytic activity of porphyrin for H2 evolution from water splitting. The H2 evolution rates of 10.8 mmol g−1 h−1 observed for H2TCFP and 9.7 mmol g−1 h−1 for H2TCTP are both larger than 8.0 mmol g−1 h−1 observed for H2TmCTP under optimal conditions. The best photocatalytic activity observed for H2TCFP was investigated through experiments and density functional theory (DFT) calculations and was interpreted in terms of the combined effect of several key factors of the entire photocatalytic process, including the high absorptivity of UV light, high separation efficiency of photogenerated carriers, and low Gibbs energy required for associated water splitting. Meanwhile, the concentration-dependent performance of photocatalytic activity was analyzed and attributed to the aggregation and light-bleaching effect exerted on porphyrins. [ABSTRACT FROM AUTHOR]

Subphthalocyanines (SubPcs) have emerged as promising organic dyes for the development of efficient artificial photosynthetic devices, offering intense absorption in the visible region along with excellent charge transport properties. In this study, four novel SubPc derivatives containing carboxylic acid and various peripheral substituents were synthesized as a panchromatic photosensitizer to prepare an efficient and stable TiO2-based photocatalytic system for co-catalyst-free photocatalytic hydrogen evolution. To compare the influence of the nature of the peripheral substituents on photocatalytic activity, SubPc derivatives (coded as SubPc 1–4) were decorated with substituents having different electron-donating capabilities, such as alkyl thio, benzodioxin, amine, and iodo units, respectively. Photocatalytic activities were examined in the presence of TEOA as a sacrificial agent under irradiation with λ > 400 nm without co-catalyst loading. SubPc 1/TiO2 shows the best photocatalytic activity among the SubPc-sensitized photocatalysts, with a hydrogen evolution rate of 0.176 mmol h−1. While the activity of all four SubPc-based photocatalysts increased significantly after 24 h irradiation, notably, SubPc 1/TiO2 exhibited remarkable catalytic activity, achieving a hydrogen evolution rate of 6.017 mmol with a high turnover number (TON) value of 12 279 for hydrogen production. This study highlights the potential of SubPc-based sensitizers for co-catalyst-free photocatalytic H2 production and offers valuable insights into the impact of peripheral units in SubPc/TiO2-based photocatalytic systems. [ABSTRACT FROM AUTHOR]

In the domain of photocatalysis, the oxygen evolution reaction (OER) serves as a crucial process in sustainable energy production. The development of efficient photocatalysts for the OER is therefore highly desirable. Two-dimensional (2D) materials, with their distinct structural and electronic properties, offer great opportunities for improving oxygen production. We propose H and H′ polymorphs of SnGe2N4 as appealing photocatalysts driving the OER using first-principles calculations together with non-adiabatic molecular dynamics (NAMD). The electronic properties and charge carrier dynamics of SnGe2N4 were evaluated, revealing insights into its potential for the OER under solar irradiation. Our findings indicate that SnGe2N4 has a favorable bandgap (∼2 eV) with appropriate band edges for the OER, promoting charge separation and transport. A significant difference in mobility facilitates electron and hole separation, leading to elevated reaction rates in the material. Moreover, the band edge alignment suggests the incorporation of water oxidation potential favoring the OER. The computed reaction pathways and free energy analysis show that SnGe2N4 can function as an effective photo-catalyst for the OER. Non-adiabatic coupling (NAC) matrix elements further ensure the ultrafast carrier dynamics, facilitating efficient charge transfer and slow recombination rates. Our findings highlight 2D SnGe2N4 as an appealing candidate for the OER. [ABSTRACT FROM AUTHOR]

A novel MOF-derived Mn2O3-decorated MoS2-graphene (MMG) composite was prepared via a facile hydrothermal method. The synthesized MMG composite was characterized through PXRD, FT-IR spectroscopy, DRS, TEM, FESEM, XPS and PL techniques. The prepared pure Mn2O3 exhibits a nano-chain-like agglomerated morphology with an average particle size of 50 nm distributed on the MoS2 and graphene layer as indicated by TEM images. DRS studies reveal a band gap of 1.22 eV for the MMG hybrid, demonstrating that the MMG hybrid can be used as a visible light–active photocatalyst. The study shows that the MMG-3 catalyst is excellent for the degradation of penicillin G under visible light with a rate constant (kapp) of 1.1 × 10−1 min. The photodegradation of PG by the MMG catalyst was found to be significantly faster than that by individual MSG or Mn2O3. The synergistic effect of MoS2 and graphene and a higher charge separation in the composite are major factors for a higher photocatalytic activity of the MMG catalyst. Moreover, the MMG catalyst exhibits good photostability, which ensures its potential applications in wastewater treatment and other energy applications. Finally, the photocatalytic mechanism of the MMG hybrid under visible light is presented after performing some radical scavenger tests. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogels have drawn significant interest in many research fields, including energy conversion and wastewater treatment. However many synthesized hydrogels show mechanical brittleness, which limits their practical application. Here, we have developed a simple, cost-effective, and eco-friendly synthesis method for the photopolymerisation of g-C3N4/polyacrylamide co-polymer hydrogel under visible light irradiation. The developed hydrogel exhibits high compressibility up to a strain of 230% with a mechanical strength of 0.55 MPa. We have addressed the dual functions of g-C3N4 in the hydrogel. First, as a photoinitiator and reinforcing agent in the polymerisation of a photocatalytic hydrogel. Second, as a photocatalyst embedded in the hydrogel for the degradation of organic dye pollutants. The three-dimensional network of the hydrogel allows rapid permeation of the cationic dye molecules into the hydrogel matrix, thereby accelerating the photodegradation process. The applicability of the synthesized photocatalytic hydrogel towards the selective degradation of different cationic dyes over anionic dyes has been determined. In addition, the synthesized hydrogel demonstrates recyclability for up to 5 cycles, without losing its photocatalytic properties. Along with this, the hydrogel shows adsorption maxima of 72 mg g−1 towards CV dye. Thus, the simple and easy preparation of the g-C3N4 based hydrogel and its excellent photocatalytic and adsorption properties have proved it to be a potential photocatalytic material for green and sustainable water remediation techniques. [ABSTRACT FROM AUTHOR]

In this study, defective UiO-66-NH2 was synthesized by a simple solvothermal method using benzoic acid and HCl as modulators, in which benzoic acid acts as a defective linker, and HCl serves as a modulator to tailor the amount of defects. The prepared MOF material with structural defects was employed for the photocatalytic reduction of Cr(VI). The results demonstrated that the prepared catalyst exhibited excellent photocatalytic activity in reducing Cr(VI), and its photocatalytic reduction rate was 5.11 times higher than that of defect-free UiO-66-NH2. The large improvement in the performance is mainly attributed to the resulting defective structure, which promotes the transfer and separation of charge carriers, reduces the recombination rate of charge carriers, enhances the adsorption capacity for Cr(VI), and increases the light absorption and specific surface area. This work provides a facile and effective strategy for the modification of MOFs and a highly efficient catalyst for photocatalytic reduction of Cr(VI). [ABSTRACT FROM AUTHOR]

Herein, mesoporous Zn-doped g-C3N4 wrapped CdIn2S4 microsphere nanostructures were fabricated using a simple hydrothermal route. It is found that the CdIn2S4/Zn–g-C3N4 nanocomposite exhibits the most efficient photocatalytic activity for hydrogen evolution. The photocatalytic activity of the CdIn2S4/Zn–g-C3N4 composite presents the optimum performance for hydrogen evolution of 101.74 μmol h−1, which is ∼10.8 and 7.3 times that of pure g-C3N4 and bare CdIn2S4, respectively. The results of varied characterization such as TEM and XPS demonstrate that a tight heterojunction has been successfully built in CdIn2S4/Zn–g-C3N4 nanocomposites, which is highly favorable to limit the recombination of photogenerated electron–hole pairs. Furthermore, Zn could partially replace the C element in the g-C3N4 framework and enhance the separation of photo-induced electrons and holes. Moreover, the incorporation of Zn-doped g-C3N4 nanosheets with mesoporous features considerably improves the photo-stability of CdIn2S4 microspheres. We hope that these CdIn2S4/Zn–g-C3N4 nanocomposites with the tight heterojunction structure may provide new insight into designing novel photocatalysts with high efficiency and excellent stability. [ABSTRACT FROM AUTHOR]

The photodegradation of propranolol (PRO) by BiOCl0.5I0.5/persulfate under visible light was comprehensively investigated. The results demonstrated a significant increase in the removal efficiency of PRO under visible light irradiation, achieved by the combination of BiOCl0.5I0.5 solid solution and persulfate (PS). The photocatalytic activity of the system was found to be enhanced with an increase in the pH value. Additionally, the addition of a certain amount of PS improved the degradation of PRO. The presence of typical water constituents, Cl− and NO3−, had a negligible impact on PRO removal. In contrast, the increasing concentration of humic acid (HA) exhibited apparent inhibition of PRO degradation. Furthermore, radical scavenging experiments revealed that the removal of PRO was primarily facilitated by active free species, including h+ and ˙O2−. The presence of characteristic peaks of ˙OH (peak ratio 1 : 2 : 2 : 1), 1O2 and ˙SO4− in the EPR spectrum indicates that these three radicals are also involved in the degradation process. Moreover, the BiOCl0.5I0.5/PS system demonstrated excellent photocatalytic activity, as well as favorable reusability and stability. This study offers new insights into the photocatalytic degradation of PRO, presenting a promising approach in this field. [ABSTRACT FROM AUTHOR]

Herein, hollow hZrO2/g-C3N4 composite photocatalysts were successfully fabricated using polymethylacrylic acid (PMAA) nanospheres as sacrificial templates via reflux-precipitation polymerization and subsequent ZrO2 layer coating by sol–gel method over PMAA nanospheres, calcining process, and forming composites with g-C3N4 in sequence. The formation mechanism of the unique composites was proved by FESEM, TEM, XPS, XRD, and EDX mapping characterizations. The photodegradation tests of methylene blue (MB) and ciprofloxacin (CIP) were used to investigate the photocatalytic activity. The results revealed that hZrO2/g-C3N4 exhibited significantly boosted photocatalytic activity for degrading 99.7% methylene blue and 81.5% ciprofloxacin in 120 min under simulated sunlight irradiation (Xe lamp, 500 W), which was much better than that of hZrO2 (42.1% for MB and 19.1% for CIP). The enhanced performance is presumably attributed to the synergetic interaction of the two components and the efficient separation of the photoproduced electron–hole pairs between ZrO2 and g-C3N4, which was verified using photocurrent and EIS characterizations. On the basis of the scavenging studies of free radicals (e−, h+, ˙O2−, and ˙OH), the mechanism of the boosted photocatalytic activity was proposed. More significantly, the composites presented excellent reusability confirmed by cyclic photocatalytic degradation experiments, which is crucial for the sustainable and green applications of photocatalysts. [ABSTRACT FROM AUTHOR]

Black phosphorene (BP) is a metal-free two-dimensional photocatalyst with potential for visible-light-driven photocatalytic H2 evolution. However, its inert basal plane toward the HER hinders its practical application. To overcome this problem, we design a novel nonprecious metal–nonmetal co-doping method of BP to activate its inert basal plane and improve photocatalytic HER performance. Through density functional theory (DFT) calculations, we systematically investigate the photocatalytic performance of nonprecious metal and nonmetal co-doped BPs. Our results show that V–N co-doped BP exhibits excellent thermodynamic stability, suitable band structure, improved carrier separation, superior adsorption and dissociation energies and enhanced visible-light absorption coefficient. Importantly, V–N co-doping successfully activates the inert basal plane of BP, allowing it to drive the HER under illumination (ΔGH = −0.12 eV). This study highlights the potential of nonprecious metal–nonmetal co-doping to enhance the photocatalytic activity of BP, providing invaluable insights for advancing the field of co-doped BP in photocatalysis. [ABSTRACT FROM AUTHOR]

Three-dimensional rose-like ZnO (R-ZnO) is an appealing photocatalyst due to its remarkable properties, while it is also essential to boost its current visible light photocatalytic performance. In this study, R-ZnO was prepared by the hydrothermal method, and oxygen vacancies and Ag nanoparticles were introduced by calcining the ZnO precursor in an argon atmosphere and the photoreduction method, respectively, to improve the photocatalytic activity. The prepared Ag/Ar-ZnO exhibits a narrower bandgap of 2.79 eV, highly increased light absorption both in the ultraviolet and visible light regions, and improved charge separation and transfer efficiencies induced by the relatively higher number of oxygen vacancies and the localized surface plasmon resonance (LSPR) effect of the Ag nanoparticles. Therefore, Ag/Ar-ZnO displays a significantly enhanced visible light photocatalytic performance, with a methyl orange (MO) photodegradation rate constant (Kap) that is 2.41 and 3.59 times higher than those of Ag-ZnO and Ar-ZnO, respectively. This research offers an effective way to enhance the photodegradation performance of R-ZnO under visible light irradiation. [ABSTRACT FROM AUTHOR]

The large band gap of La2Ti2O7 has hindered its potential application in photocatalytic water splitting under visible-light irradiation. In this study, we have utilized a passivated approach to tailor the band edges of La2Ti2O7 by combining nonmetals X (X = N and C) with metals M (M = V, Nb, Ta, Mo and W) as dopants to substitute surface O and Ti sites, respectively. The formation energies show that the synthesis of co-doped systems might be easier under O-rich conditions than Ti-rich conditions. The calculated band edges of all the passivated co-doped systems well match with visible light absorption and the oxidation or reduction potential of water. Among them, Mo and W as dopants have more remarkable influence on the narrowing of the band gap and the enhancement of the optical absorption in the visible light region. The hydrogen evolution reaction (HER) on each studied La2Ti2O7 surface is endothermic, and tends to occur on the surface O site far away from the metal dopant. The values of ΔGH suggest that (N+V)-, (2N+Mo)- and (2N+W)-doped systems exhibit higher catalytic activities toward the HER than the pure surface. The active site of the oxygen evolution reaction (OER) is the O site binding to the metal dopant. The difference in the active sites of HER and OER on the co-doped La2Ti2O7 surface is in favor of the separation of photoinduced electrons and holes. Co-doping combinations of (N+Ta), (C+Mo), and (2N+Mo) have comparable and even lower overpotential of OER than the pristine surface. Through the design, we find that (2N+Mo)-doped La2Ti2O7 may become a visible-light-responsive photocatalyst for overall water splitting based on its superior electronic, optical and photocatalytic properties. [ABSTRACT FROM AUTHOR]

In this study, the structure and electronic properties of tetratomic metal clusters of Au, Ag, and Cu decorated on graphitized carbon nitride (g-C3N4) were investigated using the density functional theory (DFT) method. The most stable structures of the complexes of Au4, Ag4, Cu4, Au2–Ag2, Au2–Cu2, and Ag2–Cu2 clusters with g-C3N4 were calculated. The molecular orbitals, partial atomic charges, and density of states of the complexes were calculated. It was noted that the HOMO–LUMO energy gap of the complexes varied depending on the type of metal cluster on the g-C3N4. The absorption spectra of the complexes were calculated and compared with the absorption spectrum of the bare g-C3N4. The electronic configurations of the calculated absorption lines in the visible region of the absorption spectrum of each complex were investigated. The absorption lines that were related to the electron excitation from an occupied molecular orbital of the complex, localized on the metal cluster, to an unoccupied orbital of the complex, localized on g-C3N4, were selected for further comparison. The electron–hole recombination rate for this type of absorption line is lower than that of the absorption lines in which the initial and final molecular orbitals are related to the g-C3N4. The prolonged electron–hole lifetime can lead to higher photocatalytic activity. [ABSTRACT FROM AUTHOR]