Transfer Of Photogenerated Electrons Research Articles

Establishing photocatalysis-self-Fenton system over a S-scheme Fe/Fe2O3@CuBi2O4 for enhancing TC removal via in-situ generating H2O2 and Fe/Cu dual-metal electron cycle: Radical and non-radical pathways

A S-scheme Fe/Fe2O3@CBO photocatalyst was synthesized via a grinding calcination method, proficiently degrading tetracycline via radicals and non-radical. The reaction rate of Fe/Fe2O3@CBO-20 was recovered to 0.0255 min−1 that is 4.3 and 7.3 times as many as pristine Fe/Fe2O3 and CBO after introducing visible light at the degradation process. The characterization outcomes also bear out that the S-scheme heterojunction is formed by passivation layer Fe2O3 and CBO, which enhances the visible light responsiveness of catalyst and promotes the separation and transfer of photogenerated electrons to generate h+ and O2−. Meanwhile, the molecular oxygen is more easily activated to form H2O2 due to the strong reduction potential of the CB (−1.21 eV), further to facilitate the transformation of O2− to 1O2. And the carriers excited in CBO activate Cu+, forming a Cu/Fe dual-metal electron cycle. The generated Fe2+ reacts with H2O2 to establish photocatalysis-self-Fenton system to generate ·OH. Additionally, the high TC removal in simulated aquatic environment exhibit that the catalytic performance is slightly affected by practical wastewater and the cyclic experiment show the stability and practicality. In conclusion, innovatively employing Fe/Fe2O3 for pollutant degradation via photocatalytic technology, this research paves a promising and efficacious pathway for the application of Fe/Fe2O3.

Magnetic-field-induced activation of S-scheme heterojunction with core–shell structure for boosted photothermal-assisted photocatalytic H2 production

Photocatalytic H2 production through water splitting using semiconductor photocatalysts offers an economical and efficient approach to generate H2 with minimal environmental pollution to alleviate the energy crisis. Maximizing the utilization of the solar spectrum and essentially accelerating the separation and transfer of photo-generated electrons are crucial for enhancing the activity of the photocatalytic H2 production systems. Herein, Mn3O4@ZnIn2S4 (MO@ZIS) core–shell heterojunction photocatalysts were meticulously designed using a convenient water bath method to obtain a system that can achieve highly efficient photothermal-assisted photocatalytic H2 production induced by a magnetic field (MF). Remarkably, the optimal photocatalytic H2 production rate up to 33.29 mmol h−1 g−1 under the effect of applied MF with an apparent quantum efficiency (AQE) of 19.93 % at 420 nm were obtained over the optimal MO@ZIS-30 photocatalyst. The substantial enhancement of the photocatalytic activity in the MO@ZIS system was attributed to the synergy of magneto-thermal effect induced by the magnetic field and the strong photo-thermal effect exhibited by MO, which significantly increases the heterojunction surface temperature of the photocatalyst and promotes the separation and transfer of photo-induced electron hole pairs, thus accelerating the surface hydrogen evolution dynamics. Furthermore, the S-scheme heterojunction formed between MO and ZIS in MO@ZIS core–shell heterojunction optimizes the carrier transfer path. This study presents an effective approach for the effective utilization of the multi-field synergistic enhancement of photocatalytic activity.

Solar-light-driven photocatalytic degradation and detoxification of ciprofloxacin using sodium niobate nanocubes decorated g-C3N4 with built-in electric field

Simultaneous degradation and detoxification during pharmaceutical and personal care product removal are important for water treatment. In this study, sodium niobate nanocubes decorated with graphitic carbon nitride (NbNC/g-C3N4) were fabricated to achieve the efficient photocatalytic degradation and detoxification of ciprofloxacin (CIP) under simulated solar light. NaNbO3 nanocubes were in-situ transformed from Na2Nb2O6•H2O via thermal dehydration at the interface of g-C3N4. The optimized NbNC/g-C3N4-1 was a type-I heterojunction, which showed a high conduction band (CB) level of −1.68 eV, leading to the efficient transfer of photogenerated electrons to O2 to produce primary reactive species, •O2−. Density functional theory (DFT) calculations of the density of states indicated that C 2p and Nb 3d contributed to the CB, and 0.37 e– transferred from NaNbO3 to g-C3N4 in NbNC/g-C3N4 based on the Mulliken population analysis of the built-in electric field intensity. NbNC/g-C3N4-1 had 3.3- and 2.3-fold of CIP degradation rate constants (k1 = 0.173 min−1) compared with those of pristine g-C3N4 and NaNbO3, respectively. In addition, N24, N19, and C5 in CIP with a high Fukui index were reactive sites for electrophilic attack by •O2−, resulting in the defluorination and ring-opening of the piperazine moiety of the dominant degradation pathways. Intermediate/product identification, integrated with computational toxicity evaluation, further indicated a substantial detoxification effect during CIP degradation in the photocatalysis system.

Study on the preparation of CdS/TiO2 corn straw biochar composite materials for photocatalytic reduction of CO2 and collaborative H2 production.

A thermal synthesis method was employed in this work to prepare CdS/TiO2 corn straw biochar photocatalytic composite materials suitable for synergistic hydrogen production with the photocatalytic reduction of CO2. The structure and synergistic reaction of these composite materials were characterized by its photogenerated electron transfer process. Compared with pure TiO2, the energy band gap of the optimal CdS/TiO2 corn straw biochar composite material was reduced to 2.89eV. The heterostructure coupling between TiO2 and CdS in the biochar accelerated the transfer of photogenerated electrons and reduced the recombination rate of photogenerated electrons and holes. Under visible light irradiation, the photocatalytic H2 yield of this CdS/TiO2 corn straw-derived biochar composite material was 1200µmol·h-1·g-1, the CO yield was 150µmol·h-1·g-1, and the CH4 yield was 55µmol·h-1·g-1. The key to this synergistic reaction is the formation of heterojunctions between CdS and TiO2 as well as the rapid oxidation of holes in the composite material caused by the doping of biochar.

Preparation and Printing Performance of Visible Light Photochromic Paper Based on PMoA-PWA/ZnO/PVP Composite

The recyclable paper based on photochromic materials not only reduces the pollution in the paper manufacture process, but also reduces the pollution caused by the use of ink, which receives wide attention. In this paper, a series of phosphomolybdic acid–phosphotungstic acid/ZnO/polyvinylpyrrolidone (PMoA-PWA/ZnO/PVP) hybrid films, which had different ratio of PMoA/PWA, was prepared by the ultrasonic composite method. The results indicated that the hybrid film prepared when the ratio of PMoA to PWA was 3 had the best photochromic performance. In this system, ZnO was the photosensitizer, while PMoA/PWA was the chromophore. The photochromic mechanism of the PMoA-PWA/ZnO/PVP hybrid film was based on the photogenerated electron transfer mechanism. ZnO generated photoelectron under the excitation of visible light, then PMoA and PWA obtained the photoelectron and produced photoreduction reaction to generate heteropolyblue. The visible light photochromic paper was prepared by loaded PMoA-PWA/ZnO/PVP hybrid film (A3) on A4 paper. Application tests showed that the prepared paper had extremely stable, excellent and reversible visible light photochromic properties, whether it was printing patterns or words, and could replace ordinary paper to realize the reuse of paper.

Decorating ZnIn2S4 with earth-abundant Co9S8 and Ni2P dual cocatalysts for boosting photocatalytic hydrogen evolution

Due to the synergistic effect of the rapid transfer of photo-generated electrons and enrichment of reactive active sites, reasonably assembling dual cocatalysts with semiconductor is considered as an excellent method to enhance the photocatalytic properties of semiconductors. Herein, earth-abundant Co9S8 and Ni2P dual cocatalysts modified-ZnIn2S4 (ZIS/CS/NP) composite photocatalyst has been constructed by the low-temperature solvothermal and in-situ photodeposition methods. A series of characterizations indicate the hollow structure of Co9S8 can reduce the charge transfer distance and enhance the migration of photo-generated electrons, while Ni2P acts as an electron collector and provides sufficient active sites for H2 release in this dual cocatalysts system. Because of the synergistic effect of dual cocatalysts, ZIS/CS/NP composites exhibit superior activity in the photocatalytic H2 production compared to blank ZIS, ZIS/CS and ZIS/NP. Notably, the optimal photocatalytic H2 production rate of ZIS/CS/NP reaches 6823.64 μmol g−1 h−1, which is approximately 86 times higher that of blank ZIS. This work is expected to provide useful reference for the construction of high-performance dual-cocatalyst modified semiconductor composite for photocatalytic H2 evolution.

Modification of electron transfer paths in CdS-TiO2 Z-type heterojunction by cobalt-based complexes for boosting visible-light photocatalytic hydrogen evolution

Ti-oxo clusters as photocatalytic heterojunction precursor materials are a promising strategy for preparing TiO2. Enhancing the utilization of photogenerated electrons and increasing the delivery channel of these electrons can improve the performance of photocatalytic materials for H2 evolution significantly. Hereby, a novel ternary [TiO2-CdS QDs-5/Co(bpy)3Cl2] photocatalyst for highly efficient photocatalytic HER was reported for the first time. In this paper, a TiO2-CdS QDs-5 binary Z-type heterojunction was identified, and the photocatalytic HER yield was further improved by [Co(bpy)3Cl2]. The above-mentioned ternary system is advantageous for separating and transferring photogenerated electron-hole pairs. The photocatalytic HER rate of this catalytic system was 4440.84 μmol·h−1·g−1, which was 7.1 times more than that of TiO2-CdS QDs-5. The results indicate that the system is capable of maintaining stability and enhancement of the photocatalytic HER under visible light irradiation. In this study, we investigated photogenerated electron transfer pathways to improve the photocatalytic HER of TiO2 and we also revealed the electron transfer mechanism of TiO2-CdS QDs-5 Z-typed heterojunction with [Co(bpy)3Cl2] through DFT calculation. More importantly, this study presents a novel Z-type heterojunction catalyst, which enhance the electron transport path and this work provides an effective design concept for the development of TiO2-based materials for efficient photocatalytic HER.

Bi & Mo co-doped In2S3 nano-foam blocks for boosted photocatalytic hydrogen generation

The design and construction of dual modifications on photocatalysts is a promising strategy to improve the photocatalytic properties. Herein, we fabricated the In2S3 nano-foam blocks with dual modifications of Bi & Mo co-doping and structure construction via a simple hydrothermal method to achieve an enhanced photocatalytic hydrogen generation. The results reveal that Bi & Mo co-doped In2S3 nano-foam blocks exhibit a high hydrogen generation rate of 5.45 mmol/g/h, which is 27 times that of bulk In2S3. Owing to the structural advantages, the enhanced specific surface area of the as-prepared nano-foam blocks improve the light harvesting efficiency of photocatalytic system. More importantly, the doped Bi and Mo atoms boost the improvement in the transfer and separation of photogenerated electrons and holes by introducing the impurity energy level. This work provides a reliable strategy for the design and fabrication of high-efficiency photocatalytic reaction system.

Photocatalytic reduction of CO2 to CO on CuS/Bi2S3: Construction of Z-type heterojunction to promote the directional transfer of photogenerated electrons

Enhancing the separation efficiency of photogenerated charge carriers and improving electron utilization are the primary challenges limiting the photocatalytic reduction performance. The utilization of heterojunctions to enhance the separation capability of photogenerated charge carriers, thereby increasing the product yield, is a common practice in the photocatalytic reduction of CO2. In this work, a composite material of CuS and Bi2S3 was synthesized via a one-step hydrothermal method, successfully constructing a Z-scheme heterojunction between the two materials. Under the influence of the heterojunction, CuS/Bi2S3 overcame the predicament of rapid recombination of photogenerated charge carriers caused by the narrow bandgap of semiconductor materials. Facilitating the accumulation of electrons at reaction sites on CuS allows for their rapid participation in reactions, leading to increased production of CO2 reduction products. The rate of CO generation from the photocatalytic conversion of CO2 using CuS/Bi2S3 was 108.57 μmol g−1h−1, representing an increase in the carbon monoxide yield by 2.78 times and 2.87 times compared to CuS and Bi2S3 respectively, and CH4 production of CuS/Bi2S3 also increased. This study offers a new understanding of the construction of heterojunctions between metal sulfides.

Photothermal flows activated CsPbBr3 ⊆ Pb-TCPP S-scheme heterojunction: In-situ converted interface for robust CO2 reduction coupling with benzylamine oxidation

By the self-sacrificial conversion approach, the perovskite CsPbBr3 nanocrystals (CPB NCs) are impregnated from a lead-porphyrin metal–organic frameworks (Pb-TCPP). Such rational design not only shapes the firm heterojunction to optimize interface electronic environment and rapid reaction kinetics. The difference on Fermi level between the parent Pb-TCPP and derived CPB dramatically could trigger electron transfer, generating a strong internal electric field. The S-scheme heterojunction not only contributes to promote the photogenerated electron transfer separation, but also endows its excellent photothermal properties, which in turn improve the reoxidation ability of the heterojunction. In-situ experimental characterization and theoretical calculations unveil electron-rich CPB acts as the CO2 activation sites and the Pb-TCPP side plays a vital role in benzylamine (BA) oxidation. The as-transferred 0.1CPB ⊆ Pb-TCPP delivers the outperformed photochemical property with a yield rate of 143.3 μmol·g−1·h−1 of CO and 18.6 μmol·g−1·h−1 of CH4, and BDA productive rate of 21.4 mmol·g−1·h−1. This work puts forward to a luxurious booster to interface phase conversion and photothermal effect in the photosynthetic fields.

Highly efficient photoreduction of CO2 to CO: Synergistic optimisation of progressive electron transfer via Fe2+ and oxygen vacancies

The electron transfer in photocatalytic reaction, including electron transfer between the components in the catalyst, electron transfer between reactant molecules and catalysts. Fe2+/Fe3+ and oxygen vacancies (VOs) were simultaneously introduced in Fe-In2O3, the 5 wt% Fe-In2O3 exhibited a 13.7-fold increase in activity (4.80 mmol·g−1·h−1) compared to the In2O3 and a CO selectivity of approximately 84.32 %. Multiple in-situ techniques indicated that the doping of FeOX serves to effectively modulate the concentration of VOs, FeOX and In2O3 form a p-n heterojunction interfacial structure and match energy bands, promoting carrier separation. More importantly, Fe2+, In2+, and VOs serve as electron-donating adsorption sites, increasing the number of electrons received by CO2 and H2O, which causing pre-reduction activation of the reactant molecules. Eventually the dual-reduction reaction of CO2 and H2O were realized, subsequently, CO2 was selectively converted into CO through intermediate species such as formate. This study employs Fe2+ and VOs to synergistic optimize the progressive transfer of photogenerated electrons, and presents a novel approach for elucidating the catalytic mechanism.

Selective photochemical oxidation of sulfides by Gallium and Sulfur Co-Modified TiO2/g-C3N4 Nanocomposites as catalyst

In this study, with the objective of promoting the oxidation of sulfides, a distinctive photocatalyst was synthesized by incorporating Ga- and S-co-doped TiO2 onto graphitic carbon nitride (g-C3N4). Under visible light irradiation, the composites demonstrated enhanced photocatalytic performance in comparison to g-C3N4 and TiO2/g-C3N4. The nanocomposite catalyst displayed a remarkable enhancement in photocatalytic activity, benefiting from the creation of a Z-scheme heterojunction by combining TiO2 and g-C3N4, as well as the presence of electron trap centers, efficient photogenerated electron transfer, improved charge carrier separation, and extended optical absorption in the visible light range. To optimize the performance, the substitution contents of Ga and S (GaxSy@TiO2-g-C3N4) were varied, where the values of x and y were set at 5 % and 10 %, respectively. Notably, Based on the obtained results, it was observed that the Ga5.0S10.0@TiO2-g-C3N4 sample displayed the highest yield when subjected to visible-light irradiation, making it the most effective and optimal sample. The findings of this study offer a fresh perspective on the synergistic effect of dopant photocatalysts in the oxidation of organic compounds. This work presents a novel approach for the development of highly efficient photocatalysts capable of effectively oxidizing organic compounds.

Carboxymethyl-β-cyclodextrin functionalized TiO2@Fe3O4@RGO magnetic photocatalyst for efficient photocatalytic degradation of tetracycline under visible light irradiation

In this study, a novel magnetic photocatalyst, carboxymethyl-β-cyclodextrin functionalized titanium dioxide@Fe3O4@reduced graphene oxide (CMCD-TiO2@Fe3O4@RGO) was successfully fabricated by a facile hydrothermal synthesis method. Raman spectroscopy, XRD, BET, FT-IR, VGM, XPS, TGA, SEM, EDS and TEM were used to characterize the photocatalysts. The photocatalytic degradation behavior of tetracycline (TC) was investigated under 420 nm light wavelengths, and the reaction mechanism was interpreted. Furthermore, the stability and reusability of CMCD-TiO2@Fe3O4@RGO were assessed. The outcomes showed that CMCD-TiO2@Fe3O4@RGO possessed higher photocatalytic activity compared with TiO2@Fe3O4@RGO, TiO2@Fe3O4 and TiO2. Under continuous irradiation at 420 nm light for 60 minutes, CMCD-TiO2@Fe3O4@RGO achieved a TC degradation efficiency of 83.3 % at a concentration of 20 mg/L. The kinetic constant for the photocatalytic degradation of TC by CMCD-TiO2@Fe3O4@RGO was determined to be 0.459 mg L−1·min−1, which was 1.49 times higher than that of TiO2@Fe3O4. The main reactive oxygen species contributing to TC degradation were determined to be ·O2- and h+. The presence of RGO and CMCD is beneficial for the adsorption of TC on the photocatalyst. Furthermore, the transfer of photo-generated electrons from the semiconductor to the RGO suppresses electron-hole recombination and enhances carrier lifetime, thereby improving photocatalytic degradation efficiency. Remarkable recyclability and stability were observed in CMCD-TiO2@Fe3O4@RGO, with only a 10.4 % reduction in TC removal after five cycles.

Photothermal-assisted photocatalytic degradation of tetracycline in simulated natural water by BiVO4/CuBi2O4 Z-scheme heterojunction: Mechanisms insight, degradation pathways and toxicity assessment

The photothermal effect generated under illumination can increase the surface temperature of the catalyst, and enhance the migration rate of the photogenerated carrier and the activity of the catalytic reaction, which is an effective way to promote photocatalytic degradation of pollutants. In this study, a Z-scheme BiVO4/CuBi2O4 (BVO-CBO) heterojunction with 0D/1D structure was prepared by hydrothermal method. Compared with pure BVO and CBO, the temperature of the Z-scheme BVO-CBO heterojunction can reach 90.1°C after 180 S illumination, and the temperature of the BVO-CBO+TC solution system can rise to 39.5°C after 10 min, which has higher heating rate and photocatalytic performance than the monomer catalyst. The experimental results showed that the photogenerated electron transfer pathway combined with the photothermal effect effectively promoted the separation of photogenerated carriers and maintained a strong redox potential, so that the removal rate of tetracycline (TC) by BVO-CBO reached 85.0 % within 90 minutes, which was significantly higher than that of pure BVO (39 %) and CBO (33 %). In addition, the toxicity of intermediate products gradually decreased during TC degradation. In addition, the effects of reaction temperature, pH, concentration of TC, common aquatic substrates and simulated natural water on TC removal were also studied. The combination of its structural advantages, redox capabilities, and photothermal effect provided a promising approach to the treatment of antibiotic-contaminated water.

Composite catalyst regenerated from spent Cu-Bi-spinel adsorbent and its Fenton-like photocatalysis mechanism for efficient removal of sulfamethoxazole

Reutilization of spent adsorbent by converting the adsorbed organic pollutants into carbon matrix has attracted more attention in recent years, which delivers a greener way for the preparation of catalysis and environment remediation. In this work, CuBi2O4 after adsorption of pollutant sulfamethazine was further transformed to a photocatalyst CBO-WC500 with high catalytic efficiency for degradation of typical pharmaceuticals. The XAFS analysis proved that Cu-C chemical bond was constructed during the preparation process. The obtained CBO-WC500 was applied to remove sulfamethoxazole (SMX) through photocatalytic Fenton-like reaction, and removal efficiency reached 88.9 % after 60 minutes with the initial 5 mg•L−1 SMX and 0.2 g•L−1 catalyst in peroxymonosulfate (PMS) system. The results showed that the introduction of carbon stem from waste improved separation of photo-generated carriers and electron transfer capability, thus more photo-induced electrons could participate in reaction with PMS. Moreover, Cu(I) and Cu(II) in CBO-WC500 with Cu-Bi-spinel structure played a vital role in PMS activation. Led by electron transportation, reactive species (1O2, •OH, SO4•-) originated from PMS contributed to degradation of SMX, and degradation pathway of target pollutant was proposed based on analysis of intermediates. Removal efficiency of CBO-WC500 for SMX kept stable after several cycles’ utilization, and it also showed decent eliminating performance of mixed pollutants in different water matrix. This study has provided a potential way for resource reuse of adsorbed pollutant and realizing reutilization of spent adsorbent as photocatalyst with higher efficiency.

MoS2–CdS composite photocatalyst for enhanced degradation of norfloxacin antibiotic with improved apparent quantum yield and energy consumption

This study introduces an advanced visible light-activated photocatalyst for the efficient degradation of norfloxacin in aqueous environments. CdS nanorods were synthesized on MoS2 through a solution-processable solvothermal method. The resulting MoS2–CdS composite exhibited exceptional photocatalytic oxidative degradation of norfloxacin antibiotic in aquatic media. The optimal degradation efficiency (87.5 %) and degradation rate constant (0.09 min−1) were achieved with the 10 wt% MoS2–CdS composite under light illumination, surpassing pure CdS nanorods by 1.5 and 2.25 times, respectively and the highest apparent quantum yield was obtained for 10 wt% MoS2–CdS composite, which is 1.5 times higher than CdS nanorod, while maintaining consistent experimental conditions. The electrical energy per order for the degradation of norfloxacin in an aqueous solution by 20 mg of CdS in 40 ml aqueous solution is 9.7 kW h m−3/order. This value reduces to 4.8 kW h m−3/order for an equal amount of 10 wt% MoS2–CdS composite. The transfer of photogenerated electrons from the CdS nanorod to MoS2 reduces the recombination probabilities of photogenerated charge carriers and consequently enhancing the photo degradation efficiency of the composite. This research may offer novel insights into the rational design and straightforward synthesis of bimetallic sulfide photocatalysts with commendable performance and cost-effectiveness for the degradation of antibiotics in aqueous environments.

CdS-based Schottky junctions for efficient visible light photocatalytic hydrogen evolution

Heterojunctions photocatalysts play a crucial role in achieving high solar-hydrogen conversion efficiency. In this work, we mainly focus on the charge transfer dynamics and pathways for sulfides-based Schottky junctions in the photocatalytic water splitting process to clarify the mechanism of heterostructures photocatalysis. Sulfides-based Schottky junctions (CdS/CoP and CdS/1T-MoS2) were successfully constructed for photocatalytic water splitting. Because of the higher work function of CdS than that of CoP and 1T-MoS2, the direction of the built-in electric field is from CoP or 1T-MoS2 to semiconductor. Therefore, CoP and 1T-MoS2 can act as electrons acceptors to accelerate the transfer of photo-generated electron on the surface of CdS, thus improving the charge utilization efficiency. Meanwhile, CoP and 1T-MoS2 as active sites can also promote the water dissociation and lower the H+ reduction overpotential, thus contributing to the excellent photocatalytic hydrogen production activity (23.59 mmol·h−1·g−1 and 1195.8 mol·h−1·g−1 for CdS/CoP and CdS/1T-MoS2).

Biotemplated Fe/La-co-doped TiO2 for photocatalytic depth treatment of compressed leachate from refuse transfer station.

Compressed leachate is a contaminated liquid containing various organic and inorganic pollutants produced in municipal refuse transfer stations, which pollute soil and groundwater, posing serious risks to the environment and human health. The Environmental Technology Co., Ltd. (Shenzhen, Guangdong Province, South China) treated compressed leachate obtained from a refuse transfer station. The chemical oxygen demand (COD) (641.2mg/L) of treated compressed leachate did not meet the wastewater quality standards in China for discharge into municipal sewers (COD ≤ 500mg/L) and the company's design discharge requirements (COD ≤ 400mg/L). Therefore, their further in-depth treatment is necessary. To this end, waste tobacco leaves were used as the biotemplate herein, and Fe/La-co-doped TiO2 (xFe,yLa)-TTiO2(g) was synthesized using a solvothermal-assisted biotemplating method. The photocatalytic depth treatment of compressed leachate was performed under simulated solar light using the prepared catalysts. After (3Fe,3La)-TTiO2(g) treatment, the COD of the leachate decreased from 641.2 to 280.1mg/L, and the COD removal rate was 1.2, 1.1, and 1.6 times higher than that of pure Fe-doped, La-doped and non-biological template TiO2, respectively. Characterization confirmed that the biological template endowed the catalyst with a unique morphology and high specific surface area. Its rich activity sites are conducive to enhancing the adsorption capacity of pollutants and providing an ideal place for photocatalytic reactions. Co-doping with iron and lanthanum ions altered the band structure of TiO2 and promoted the interconversion of Fe3+/Fe2+ and La3+/La2+ during photocatalysis. First-principles density functional theory simulations demonstrated that co-doping Fe and La in TiO2 created impurity levels that facilitated the transfer of photogenerated electrons. This study provides a new purification pathway for the depth treatment of compressed leachate.

Preparation of nanosheet g-C3N4 coupled with Polycalix [4] resorcinarene: Survey characterization and photocatalytic activity for the degradation of 4-Nitrophenol

Here, we have synthesized Polycalix[4]resorcinarene (PC4RA) covalently coupled with carbon-modified porous graphitic carbon nitride (g-C3N4). The nanocomposites were characterized by (FTIR), (XRD), (SEM), Transmission (TEM), and DRS–UV–Vis spectroscopic methods. Photocatalytic activities of the PC4RA/g-C3N4 nanocomposites with different ratios of g-C3N4 were evaluated for degradation of 4-Nitrophenol under visible light irradiation under light irradiation of λ ≥ 320 nm. Three parameters were applied including the initial concentration of 4-nitrophenol, the amount of photocatalyst, and irradiation time. and the results of the photocatalytic performance suggest that the catalytic activity is strongly influenced by the presence of the g-C3N4 content. Especially the nanocomposite’s photocatalytic efficiency was the highest (98.32 % after 120 min) when the ratio of g-C3N4 was (1/2). However, an increase of the photocatalytic activities was related to the interfacial transfer of photogenerated electrons and holes, leading to the effective charge separation. The durability and stability of the nanocomposites have been examined and can endure the experimental conditions even after eight successive cycles. This approach opens up an avenue for the fabrication of graphitic carbon nitrite-based metal-free heterogeneous nanocomposites with high catalytic performance.

Embedding ZnCo2O4 quantum dots onto graphdiyne (g-CnH2n-2) nanosheets as a 0D/2D S-scheme heterojunction for highly efficient photocatalytic H2 evolution

The design of environmentally friendly and cost-effective S-scheme heterojunctions with robust interfacial interactions is pivotal for enhancing photocatalytic performance and facilitating practical application. In this work, ZnCo2O4 quantum dots (QDs)/graphdiyne (ZCOG) S-scheme heterojunction was synthesized by a simple hydrothermal method. ZnCo2O4 QDs with quantum size effect were prepared by calcination, while graphdiyne (GDY) nanosheets were synthesized by reduction-elimination reaction using CuBr as catalyst. The maximum hydrogen production rate of ZCOG reaches 2472.80 μmol g-1h−1, which is 30.75 and 10.84 times higher than that of ZnCo2O4 QDs and GDY, respectively. This significantly enhanced photocatalytic activity is attributed to the strongly coupled S-scheme heterojunction between GDY and ZnCo2O4 QDs, which accelerates the photogenerated electron transfer while effectively suppressing the recombination of photogenerated carriers. In addition, the quantum size effect of the ZnCo2O4 QDs leads to an increase in the width of the electronic forbidden band, which enhances the energy of electrons (holes) in the conduction band (valence band). The S-scheme mechanism of ZCOG was revealed by in situ XPS, UPS and TRPL spectroscopy, and the reliability of the conclusions was further verified by DFT calculations. This work provides an efficient strategy for the construction of GDY-based photocatalysts with quantum size effect.