Mechanism Of Photocatalytic Oxidation Research Articles

Role of Hydroxyl Groups in Zn-containing Nanosized MFI Zeolite for the Photocatalytic Oxidation of Methane.

The effective conversion of methane to a mixture of more valuable hydrocarbons and hydrogen under mild conditions is a significant scientific and practical challenge. Here, we synthesized Zn-containing nanosized MFI zeolite for direct oxidation of methane in the presence of H2O and air. The presence of the surface hydroxyl groups on nanosized MFI-type zeolite and their significant reduction in the Zn-containing nanosized MFI zeolite were confirmed with Infrared Fourier Transform (FTIR) spectroscopy. Incorporation of zinc atoms into the framework of nanosized MFI zeolite is revealed by Nuclear Magnetic Resonance, X-ray Diffraction and UV-Vis Spectroscopy. Unexpectedly, pure silica MFI zeolite exhibited the highest photocatalytic performance. Our findings demonstrated that large number of isolated silanol groups and silanol nests increase the formation of ⋅OH, and enhance the productivity of oxygenate compounds and C2H6, while the Zn incorporated into the zeolite framework or attached to the silanol nests of the nanosized zeolites are less efficient. A mechanism of photocatalytic methane oxidation is proposed. These findings provide insights into the development of active nanosized zeolite photocatalysts with an extended amount of surface hydroxyl groups that can play a key role in photocatalytic methane conversion.

Role of H2O2 as Oxidant and H2O as Co-catalyst over Anatase-TiO2 (101) for Conversion of Methane to Methanol.

Computations based on density functional theory are carried out to examine the mechanism of photocatalytic oxidation of methane to methanol with H2O2 as oxidant and water as co-catalyst over anatase TiO2 (101) surface. The reaction proceeds with hydrogen abstraction from methane followed by the formation of surface methoxy species, which is reduced to methanol. We compare the reaction energetics for C-H dissociation in the presence and absence of surface defect, but find no discernible impact of O-vacancy on methane oxidation. In comparison, hydroxyl produced as a result of H2O2 or H2O photo-decomposition dramatically reduces the barrier for CH3-H bond cleavage. The reaction proceeds further by the reduction of surface methoxy group and is the rate-limiting step for methanol formation. Additionally, we find that methyl can also react with water to form methanol with a considerably lower barrier, suggesting an active involvement of water for methanol formation. We also study the role of water as a co-catalyst and observe significant reduction in barriers, facilitated by alternate pathway for proton transfer. The reaction pathways presented provide valuable in- sights into the mechanism of methane oxidation in the presence of H2O2 as oxidant and demonstrate the rate-enhancing role of water for these steps.

Nd3+ induces three-dimensional hierarchical rosette-shaped Bi3O4Br to generate abundant oxygen vacancies for enhanced photocatalytic activity

Three-dimensional hierarchical rosette-shaped Bi3O4Br has been successfully prepared by a one-step hydrothermal method for the first time, in which the doping of Nd3+ into the matrix of Bi3O4Br induces abundant oxygen vacancies and triggers energy-band hybridization to produce new dopant levels, which can efficiently receive photo-excited electrons and inhibit the complexation of photogenerated carriers. Impressively, the doped energy levels act as “springboards” for photogenerated electron jumps, exacerbating the inhomogeneity of charge distribution and accelerating charge separation. In addition, the fine-tuning of Nd3+ improves the band structure and photocatalytic performance of Nd/Bi3O4Br. Notably, the unique 3D rosette-like Bi3O4Br could enhance the adsorption capacity of the catalyst and provide more opportunities for the introduction of Nd3+ to induce the generation of abundant oxygen vacancies. Both experimental and density functional theory (DFT) results reveal the synergistic effect of energy band hybridization and oxygen vacancies. In addition, comparative experiments showed that Nd/Bi3O4Br enhanced the maximum removal efficiency of heavy metal mercury by 29.66 % relative to Bi3O4Br under visible light. The present work reveals the reaction mechanism of photocatalytic oxidation for mercury removal, which provides a new direction for realizing energy conversion and environmental purification in the future.

Preparation of Soybean Dreg-Based Biochar@TiO2 Composites and the Photocatalytic Degradation of Aflatoxin B1 Exposed to Simulated Sunlight Irradiation.

Aflatoxin B1 (AFB1) is a highly toxic carcinogen severely harmful to humans and animals. This study fabricated SDB-6-K-9@TiO2 composites via the hydrothermal synthesis method to reduce AFB1. The structural characterization results of the photocatalytic composites showed that TiO2 was successfully loaded onto SDB-6-K-9. The different photocatalytic degradation conditions, photocatalyst kinetics, recycling performance, and photocatalytic degradation mechanism were investigated. Photocatalysis with 6 mg of 4%SDB-6-K-9@TiO2 in a 100 μg/mL AFB1 solution presented a reduction of over 95%, exhibiting excellent performance, high stability, and reusability even after five cycles of photocatalytic experiments. Active species trapping experiments confirmed that holes (h+) played the most critical role. After structural analysis and identification of the photocatalytic degradation products, the photodegradation path and photocatalytic oxidation mechanism of 4%SDB-6-K-9@TiO2 were postulated. The results show a new way to improve TiO2's photocatalytic performance, providing a certain theoretical basis for the effective AFB1 reduction.

Facile synthesis of Sb2WO6 with gradient oxygen vacancies for high photocatalytic activity

The Sb2WO6 photocatalyst is synthesized by introducing oxygen vacancies through acetylene annealing. The number of oxygen vacancies can be adjusted by varying the annealing duration. Oxygen vacancy defects in Sb2WO6 change the surface chemical properties, enhance the separation of carriers, broaden the absorption of visible light, and activate the catalytic sites, resulting in overall enhancement of the photocatalytic properties. The significance of surface oxygen vacancies and pertinent mechanisms of photocatalytic oxidation are described. Our results reveal a promising method to improve the properties of Sb2WO6-based materials for applications such as the treatment of wastewater.

Highly selective aerobic oxidation of cyclohexane by flower-like MoO3-x microspheres-nitrogen-doped carbon dots heterojunction

Due to the higher susceptibility of alcohols and ketones to oxidation compared to alkanes, converting inert C-H bonds in alkanes into high value-added product KA oil with high selectivity is still a significant obstacle. In this study, flower-like microspheres of MoO3-x, featuring aligned nanosheets and oxygen vacancies, were combined with nitrogen doped carbon dots (NCDs) to fabricate S-scheme heterojunctions of MoO3-x-NCDs for boosting the photocatalytic efficiency in oxidizing cyclohexane. Because of the oxygen vacancies-triggered localized surface plasmon resonance (LSPR) and the S-scheme charge transfer mechanism, there was a significant improvement in the absorption of visible light and an enhancement in the efficiency of charge separation. The MoO3-x-NCDs composites exhibited a notably improved catalytic performance in cyclohexane oxidation. The MoO3-x-NCDs composite exhibited remarkable selectivity of KA oil in catalyzing cyclohexane oxidation under light exposure, attributed to the substantial increase in cyclohexane adsorption capacity. The highest cyclohexane transformation rate of 9.98 % was achieved by MoO3-x-NCDs-2 composites with a MoO3-x/NCDs ratio of 50:1, outperforming bare MoO3-x by 1.81 times, while exhibiting a KA oil selectivity reaching 93.75 %. The mechanism of selective photocatalytic oxidation was explored using photoelectric examination, analysis of energy bands, and evaluation of active radicals. In this research, green photocatalysts were fabricated through the utilization of NCDs, enabling efficient conversion and selective oxidation of cyclohexane in gentle environments. This innovative approach holds great potential for advancing the field of photocatalysis.

Insight on photocatalytic synchronous oxidation and reduction for pollutant removal: Chemical energy conversion between macromolecular organic pollutants and heavy metal

Collaborative treatment of pollutants is a promising approach for wastewater treatment. In this work, a covalent organic framework material (COFs) with an imine structure was synthesised by the Schiff base reaction, and photochemical tests showed good photochemical effects. It was used to explore the photocatalytic treatment of co-existing pollutants (heavy metal ions and antibiotics) and the performance of treating co-existing wastewater was investigated. The degradation performance of levofloxacin (LVX) and Cr(VI) was improved in the coexisting pollutants system, with the LVX degradation being 4.2 times more effective than that of the LVX solitary system. Moreover, this phenomenon was also observed in LVX/Ag(I), LVX/Fe(III), sulfadiazine/Cr(VI), norfloxacin/Cr(VI) and tetracycline/Cr(VI) systems. The analysis of active species suggesting that the synergistic promotion of photocatalytic oxidation-reduction systems was not only promoting from the improvement of simple charge separation, but it was also found that high-valent metal species can act directly in the oxidative decomposition of antibiotics. The interaction of pollutants and intermediates were rationally exploited and confirmed by control experiments and theoretical calculation. This conclusion helps us to re-examine the underlying mechanisms of photocatalytic synchronous oxidation and reduction reactions, simultaneously beneficial for the development of mixed pollutant control processes.

Photocatalytic Degradation of Naproxen: Intermediates and Total Reaction Mechanism.

Photochemical and photocatalytic oxidation of naproxen (NPX) with UV-A light and commercial TiO2 under constant flow of oxygen have been investigated. Adsorption experiments indicated that 90% of the solute remained in the solution. Combined chemical analysis of samples on the photochemical degradation indicated that NPX in an aqueous solution (20 ppm) is efficiently transformed into other species but only 18% of the reactant is mineralized into CO2 and water after three hours of reaction. Performing the photocatalytic oxidation in the presence of TiO2, more than 80% of the organic compounds are mineralized by reactive oxidation species (ROS) within four hours of reaction. Analysis of reaction mixtures by a combination of analytical techniques indicated that naproxen is transformed into several aromatic naphthalene derivatives. These latter compounds are eventually transformed into polyhydroxylated aromatic compounds that are strongly adsorbed onto the TiO2 surface and are quickly oxidized into low-molecular-weight acids by an electron transfer mechanism. Based on this and previous studies on NPX photocatalytic oxidation, a unified and complete degradation mechanism is presented.

Constructing a Z-Scheme Co3O4/BiOBr Heterojunction to Enhance Photocatalytic Peroxydisulfate Oxidation of High-Concentration Rhodamine B: Mechanism, Degradation Pathways, and Toxicological Evaluations.

Photocatalytic coupling technologies have emerged as popular strategies to increase the treatment efficiency of dye-containing wastewater. Herein, the Z-scheme Co3O4/BiOBr heterojunction (Z-CBH) was constructed and developed as a photocatalytic peroxydisulfate (PDS) activator for the degradation of high-concentration Rhodamine B (RhB). Multiple testing techniques were employed to confirm the formation of Z-CBHs. When 0.1 g·L-1 of Z-CBH20 and 1.0 mmol·L-1 of PDS were added simultaneously under simulated sunlight irradiation, the RhB degradation efficiency could approach 91.3%. Its reaction rate constant (0.01231 min-1) was much beyond the sum of those in the Z-CBH20/light system (0.00436 min-1) and the PDS/light system (0.0062 min-1). h+, •OH, •O2-, SO4•-, and 1O2 were detected as the dominant reactive species for RhB degradation. The potential mechanism of photocatalytic PDS oxidation was proposed. The possible intermediates were determined by high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry assisted with density functional theory and Fukui theory. The possible degradation pathways of RhB degradation were put forward. The toxicological properties of RhB and its intermediates were evaluated by quantitative structure-activity relationship prediction. This work will not only provide a reference for developing photocatalytic persulfate activators but also gain an insight into the degradation pathways of RhB and the toxicity of its intermediates.

Photocatalytic oxidation mechanism of isoprene over titanium oxide by UV–Vis lights

Isoprene is an important precursor of tropospheric ozone due to its high ozone formation potential and widespread biogenic sources. However, its control technology has not received sufficient attention. Here we investigate the photo-catalytical oxidation performance and mechanism of isoprene over a TiO2 (P25) catalyst. The mean conversion is (46.1 ± 3.7)% with a corresponding CO2 selectivity of (84.3 ± 0.3)% in humidified air when irradiated by UV–Vis lights (350–760 nm) in a flow system, with a reactor volume space velocity of 2647 h−1 for 670 ppb isoprene. Relative humidity has little influence on the activity. Electron holes dominantly initiate the oxidation of isoprene, leading to the formation of C5H8, followed by organic peroxides, and other intermediates in the presence of O2 and H2O as supported by results from radical-trapping experiments, as well as in situ surface and gas-phase product analysis. Our results suggest that the P25 is a promising catalyst for removing ambient isoprene.

The improvement of photocatalytic activity of BiVO4 modified with Co(OH)2 nanoflake arrays for photocatalytic and photo-electrocatalytic desulfurization

Various and economical pure BiVO4 and Co(OH)2 nanoflake deposited BiVO4 photocatalysts have been prepared using the electrodeposition technique. Improved photocurrent density of 64 µA/cm2 at 1.0 V vs. Ag/AgCl was shown by Co(OH)2-BiVO4-150 photoanode (BiVO4 after 150 s of cobalt electrodeposition), which is about 8 times higher compared with BiVO4 photoanode. The catalysts prepared have also been used in the photocatalytic oxidation of dibenzothiophene (DBT), which is applied to stimulate fluid catalytic cracking for gasoline production in n-heptane solution. The corresponding parameters in the optimization of oxidative desulfurization of DBT were reaction time, temperature, solvent, DBT concentration and electrical bias voltage. The highest DBT desulfurization efficiency was shown by Co(OH)2-BiVO4-150. Based on the mechanism of photocatalytic oxidation, the superoxide and hydroxyl radicals played major parts in DBT degradation. Co(OH)2-BiVO4-150 photoanode showed better photo-electrocatalytic degradation efficiency, reaching a high 78.3% DBT removal even during the reaction time, in comparison with photocatalysis and electrocatalysis. The photocatalytic degradation system containing Co(OH)2-BiVO4-150 may be recycled six times without any important reduction of photocatalytic activity. This procedure introduces a simple and sustainable approach for the modification of BiVO4 to improve its photoelectrochemical and photocatalytic activity.

Ba3(PO4)2 Photocatalyst for Efficient Photocatalytic Application.

Barium phosphate (Ba3(PO4)2) is a class of material that has attracted significant attention thanks to its chemical stability and versatility. However, the use of Ba3(PO4)2 as a photocatalyst is scarcely reported, and its use as a photocatalyst has yet to be reported. Herein, Ba3(PO4)2 nanoflakes synthesis is optimized using sol-gel and hydrothermal methods. The as-prepared Ba3(PO4)2 powders are investigated using physicochemical characterizations, including XRD, SEM, EDX, FTIR, DRS, J-t, LSV, Mott-Schottky, and EIS. In addition, DFT calculations are performed to investigate the band structure. The oxidation capability of the photocatalysts is investigated depending on the synthesis method using rhodamine B (RhB) as a pollutant model. Both Ba3(PO4)2 samples prepared by the sol-gel and hydrothermal methods display high RhB photodegradation of 79% and 68%, respectively. The Ba3(PO4)2 obtained using the sol-gel process exhibits much higher stability under light excitation after four regeneration cycles. The photocatalytic oxidation mechanism is proposed based on the active species trapping experiments where O2 •‒ is the most reactive species. The finding shows the promising potential of Ba3(PO4)2 photocatalysts and opens the door for further investigation and application in various photocatalytic applications.

Cubic S/N co-doped TiO2 with rich oxygen vacancies from Ti-MOFs for efficient elimination of formaldehyde

The cubic S/N co-doped TiO2 (TNSx, x is the calcination temperature) photocatalysts with rich oxygen vacancies were obtained by high temperature calcination of sulfur powder and titanium-based MOFs NH2-MIL-125 for the photocatalytic removal of gaseous formaldehyde (a volatile organic compound). Among the obtained catalysts, the presence of oxygen vacancies restricted photogenerated electron and holes recombination. 98.00% removal of gaseous formaldehyde in 150 min could be achieved over TNS600 by xenon lamp. The removal efficiency for formaldehyde was well retained for five cycle experiment. The results from PL, TRPL and EIS revealed that TNS600 had the best separation efficiency of photogenerated electrons and holes, and the enhanced charge separation led to a significant increase in photocatalytic activity. The photocatalytic oxidation mechanism indicated that the •OH and •O2− radicals were mainly involved in the efficient elimination of gaseous formaldehyde and were able to mineralize formaldehyde to H2O and CO2.

TiO2-Decorated by Nano-γ-Fe2O3 as a Catalyst for Efficient Photocatalytic Degradation of Orange G Dye under Eco-friendly White LED Irradiation.

Azo dyes make up a major class of dyes that have been widely studied for their diverse applications. In this study, we successfully applied nano-γ-Fe2O3/TiO2 as a nanocatalyst to improve the photodegradation efficiency of azo dyes (Orange G (OG) dye as a model) from aqueous solution under white light-emitting diode (LED) irradiation. We also investigated the degradation mechanisms and pathways of OG dye as well as the effects of the initial pH value, amount of H2O2, catalyst dosage, and dye concentration on the degradation processes. The characterizations of nano-γ-Fe2O3 and γ-Fe2O3 Nps/TiO2 were carried out using various techniques, including X-ray diffractometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and UV-visible spectroscopy. The efficiency of the photodegradation reaction of OG was found to follow pseudo-first-order kinetics (Langmuir-Hinshelwood model) with a rate constant of 0.0338 min-1 and an R2 of 0.9906. Scavenger experiments revealed that hydroxyl radicals and superoxide anion radicals were the dominant species in the OG photocatalytic oxidation mechanism. This work provides a new method for designing highly efficient heterostructure-based photocatalysts (γ-Fe2O3 Nps/TiO2) based on LED light irradiation for environmental applications.

Mechanism of action of the heterojunction structure of the photocatalyst ZnO-g-C3N4@TiO2 and its application to the degradation of acetaminophen

Acetaminophen, a non-steroidal anti-inflammatory drug, is one of the most abundant drugs and personal care products in natural water bodies, and the amount of acetaminophen (APAP) has increased dramatically during COVID-19. Photocatalysis is an advanced oxidation technology with high degradation and mineralization capacity and is environment-friendly, and it is important to design new photocatalysts to improve APAP removal efficiency and investigate the mechanism of photocatalytic oxidation. In this study, two kinds of photocatalysts, g-C3N4@TiO2 (gT) and g-C3N4@TiO2@ZnO (gTZ) were prepared by the sol–gel method and sol–gel heat condensation method. Secondly, they were systematically characterized by SEM, XRD, BET, XPS, UV–vis DRS, steady-state photoluminescence (PL) spectroscopy, and contact angle, and their energy band structures were analyzed and inferred to be composite type II heterojunction photocatalysts. The photocatalytic efficiency was investigated by degrading the pollutants APAP and azo dyes. The degradation rates of gT and gTZ for APAP were 70.6% and 92.4% under 254 nm UV light, respectively. Finally, the main radicals of gTZ for the degradation of APAP were hydroxyl radicals (•OH), which were investigated by the free radical capture, and then eight intermediates for the photocatalytic degradation of APAP were obtained by HPLC-MS/MS, which led to the photocatalytic degradation pathway.

Fabrication of BiOIO3/g-C3N4/Er3+ containing oxygen vacancies for photocatalytic oxidation of gaseous elemental mercury

Construction of heterojunction and formation of oxygen vacancy are effective methods to improve the performance of photocatalysts. In this work, Er3+-doped BiOIO3/g-C3N4 photocatalyst with oxygen-rich vacancies was prepared by a simple hydrothermal and calcination method for the photocatalytic oxidation of elemental mercury. The structural properties of BiOIO3/g-C3N4/Er3+ were analyzed by XRD, SEM and BET. The results showed that all samples exhibited good photocatalytic oxidation ability for Hg0 under visible light irradiation. Among them, the photocatalyst with Er3+-doped BiOIO3/g-C3N4 and then calcined has the highest removal efficiency of Hg0, which is 68.83%. This may be due to the increase of oxygen vacancy caused by Er3+ doping, which enables the photocatalyst to have higher electron transfer rate and wider visible light absorption range. Finally, the possible mechanism of photocatalytic oxidation of gaseous elemental mercury with BiOIO3/g-C3N4/Er3+ photocatalyst was proposed. This study provides some reference for the design and application of photocatalysts containing oxygen vacancies.

Fabrication of New TiO2 Photocatalyst for Removing Organic Dyes and Hazardous VOCs in Air Purifier System

We synthesized an amorphous Ti-based hydroperoxo complex (ATPC) using a facile method involvingonly titanium hydride (TiH2) and H2O2 under mild conditions. We chose TiH2 as the precursor because it has more reactive sites than metal oxides such as TiO2. Qualitative and quantitative optical measurements showed that our synthesized ATPC photocatalysts contained many hydroperoxo groups and various oxidation states of Ti (Ti2+, Ti3+, and Ti4+). Thus, the synthesized ATPC exhibits excellent photocatalytic properties with very fast rates of organic decolorization compared to other conventional visiblelight catalysts. The presence of many hydroperoxo complexes increases the formation of active radicals, which can degrade VOCs such as acetaldehyde in a gas phase. To test the application of the synthesized ATPC, we fabricated a filter system in an air purifier using ATPC coating layers and successfully removed the VOCs. We also proposed a possible photocatalytic oxidation mechanism with ATPC based on this study. It is important to conduct application tests as well as commercialization in photocatalytic experiments.

Integrated Nanostructures of TiO2/g-C3N4/Diatomite Based on Low-Grade Diatomite as Efficient Catalyst for Photocatalytic Degradation of Methylene Blue: Performance and Mechanism

The comprehensive utilization of low-grade diatomite resources and the effective treatment of printing and dyeing wastewater have attracted widespread attention. The combined scrubbing-magnetic separation-acid leaching-roasting process was used to increase the SiO2 content from 59.22% to 86.93%, reduce the Al2O3 content from 18.32% to 6.75%, and reduce the Fe2O3 content from 6.85% to 1.24% in the low-grade diatomite from Heilongjiang, China. The TiO2/g-C3N4/diatomite nanocomposite was prepared by a facile ultrasonic-thermal polymerization method. In this ternary structure, diatomite skeleton effectively increased the surface area with abundant adsorption sites, prevented g-C3N4 from restacking, and facilitated the separation of electrons and holes via the formation of TiO2/g-C3N4 heterojunctions. The degradation rate was 98.77%, 90.59%, and 89.16% for the three catalytic reaction cycles of the MB solution, respectively. The composite showed a high degradation rate of the MB solution after three cycles, which indicated that the composite had good recyclability. Through the free radical capture test, it was elucidated that O2−·, h+, and ·OH all played a role in the photocatalytic reaction of the TiO2/g-C3N4/diatomite to the MB solution, in which O2−· was mainly responsible for the photocatalytic oxidation mechanism, and the reaction kinetics were further investigated. This nanostructured TiO2/g-C3N4/diatomite composite has fascinating visible light catalytic activity and excellent stability.

Rules for selecting metal additives based on electron structure and HCHO oxidation efficiency between modified-TiO2(B) photocatalyst and metal cocatalyst Pd/Cu/Na

Metal additives can greatly improve the catalytic oxidation of photocatalysts for degrading volatile organic compounds (VOCs) including formaldehyde. Different type metal, including Pd, Cu and Na, were doped in TiO2(B) nanosheets with oxygen vacancy, and the degradation rate of HCHO were evaluated using the above catalysts. A series of theoretical and experimental studies on these modified TiO2(B) photocatalysts were carried out. The presence of Ov leads to the appearance of impurity levels under the conduction band of TiO2(B), which could enhance the absorption in the visible spectral range by reducing the band gap and inhibiting the recombination of photo-induced charges. TiO2(B) with oxygen vacancies and doped with Na is used as a photocatalyst for degrading HCHO, and the removal rate up to 80% within 50 min. It is quite important to match the bandgap structure of photocatalysts and redox potential of O2/•O2−. Doping of excessive metals is detrimental to the separation and transfer of photogenerated charges. The intermediates and mechanism of photocatalytic oxidation of HCHO were investigated by in situ DRIFTS.

Controllable synthesis for carbon self-doping and structural defect co-modified g-C3N4: Enhanced photocatalytic oxidation performance and the mechanism insight

For the purpose of improving the photocatalytic performance of graphitic carbon nitride (g-C3N4) in the field of contaminant elimination, an in-situ malonamide-assisted strategy is provided to prepare carbon self-doping and structural defect co-modified g-C3N4 (CDCN) via preprocessing of the mixture of urea and malonamide followed by thermal copolymerization. Changing the initial malonamide dosage can precisely adjust the carbon doping level and structural defect concentration of CDCN. The characteristic results confirm that the doped C derived from malonamide was successfully implanted into the g-C3N4 framework by replacing sp2 hybrid N atoms (C−N=C) in the heptazine units, simultaneously forming some structural defects. Additionally, the preprocessing endows CDCN with good textural properties. So, the optimal CDCN20 shows remarkably enhanced visible-light photocatalytic activity in eliminating acetaminophen (APAP) and methylparaben (MPB) in water than pristine g-C3N4. By combining experimental and theoretical calculating results, the synergistic effect of C self-doping and structural defect promoting the photocatalytic performance of g-C3N4 is revealed thoroughly. This work provides a controllable strategy for synthesizing effective C self-doped g-C3N4 and a new insight into electronic structure and band structure-regulated photocatalytic oxidation mechanisms.