Photocatalytic NO Oxidation Research Articles

Enhanced Photocatalytic Activity of Nickel(II)‐Doped Bi2O2CO3 Nanosheets for Efficient Nitric Oxide Removal

Bi2O2CO3 is a typical bismuth‐based semiconductor photocatalyst that has attracted much attention because of layered structure and polarization characteristics. However, the wide bandgap of Bi2O2CO3 limits its practical applications in photocatalysis. In this study, the nickel‐doped Bi2O2CO3 (Ni2+‐Bi2O2CO3) was prepared by adding a controllable amount of nickel ions. The photocatalytic efficiency of the optimized sample for ppb‐grade NO under visible light irradiation is 59.4%, which is 2.8 times than that of its counterpart, Bi2O2CO3 (21.2%). Based on experiments and characterizations, Introduction of nickel ions improves the photocatalytic performance of Ni2+‐Bi2O2CO3, which not only lowered the bandgap from 3.25 eV to 2.92 eV, but also reduced the recombination of photogenerated carriers by formation of the impurity level. Furthermore, the adsorption and photocatalytic conversion pathway of NO was explored by in situ DRIFTS, the principal byproducts of photocatalytic oxidation of NO are NO3− and NO2−. This work offers a new perspective to improve the photocatalytic activity by doping mothed for air purification.

Synthesis of CdS QDs/NH2-Nb2O5 via electrostatic self-assembly method for highly efficient photocatalytic removal of NO and synchronous inhibition of NO2

A two-step electrostatic self-assembly method was used to first graft –NH2 groups onto the Nb2O5 followed by loading of CdS QDs onto the NH2-Nb2O5 to obtain CdS/NH2-Nb2O5. The performance of the samples under visible light was evaluated under simulated conditions of 25 °C and varying relative humidity (RHs). The results showed that with the increase of RH, the NO removal efficiency by CdS/NH2-Nb2O5 increased first and then decreased, reaching the maximum NO removal efficiency when RH = 50 %. The selectivity of NO2 on CdS/NH2-Nb2O5 (9.01 %) was significantly lower compared to that of Nb2O5 (24.44 %) and NH2-Nb2O5 (19.72 %). The introduction of –NH2 groups and CdS QDs significantly enhanced visible light absorption and improved the separation efficiency of photogenerated charge carriers. In-situ DRIFTS analysis revealed that Cd2+ served as an additional active site for NO adsorption. Furthermore, CdS had a relatively negative conduction band position, which was conducive to the generation of O2–, further inhibiting the generation of NO2. This work provides a new approach to the design and preparation of catalysts for photocatalytic oxidation of NO.

Effect of precursors on the structure and photocatalytic performance of g-C3N4 for NO oxidation and CO2 reduction

Graphitic carbon nitride (g-C3N4, CN) is recognized as the most extensively studied organic polymeric photocatalyst for pollution control and energy conversion due to its facile synthesis and suitable electronic band structure. The aim of the present work is to explore the effect of precursors, such as urea (U, (NH2)2CO), dicyandiamide (D, C2H4N4) and melamine (M, C3H6N6), on the structure and photocatalytic activity of the obtained CN samples, denoted as UCN, DCN and MCN, respectively. The sheet-like UCN sample shows significantly enhanced photoreactivity in both NO oxidation and CO2 reduction compared to the bulk DCN and MCN materials. In addition, UCN demonstrates the ability to suppress the formation of toxic NO2 intermediate during the photocatalytic oxidation of NO. The improved photocatalytic activity of UCN can be attributed to a dual effect: first, its increased specific surface area provides more active sites for the photocatalytic reaction; second, it exhibits a stronger affinity for substrates like NO and CO2, which facilitates charge migration at the interface.

The in-situ fabricated Bi nanoparticles on the BiOBr efficiently inhibit the production of toxic by-product NO2 during the photocatalytic NO oxidation

In this study, bismuth nanoparticles (NPs) are reduced in-situ on the BiOBr surface to enhance the electron transfer rate. The formation of Bi NPs is directly confirmed by characterizations such as XRD, TEM and XPS. Meanwhile, UV–Vis, PL characterization analysis and DFT theoretical calculation suggest that Bi NPs not only broaden the photoresponse range but also form a fast charge-transfer channel with the BiOBr. The results demonstrate that the NO removal rate of the optimal sample (BiOBr-1.5) is about 48.93%, which is 6.5 times that of the original BiOBr, and almost no toxic by-product NO2 is produced. This study provides a valuable strategy for designing photocatalysts that remove NO while effectively suppressing toxic by-products.

Epitaxial growth of Bi4Ti3O12-BiPO4 Z-scheme heterojunction to promote carrier transfer for photocatalytic oxidation of NO

The lack of compactness in heterojunction interfaces and poor charge separation is a great challenge in developing high-efficiency heterojunction photocatalysts. Herein, a novel Bi4Ti3O12-BiPO4 heterojunction was successfully prepared for the first time by epitaxial growth of BiPO4 on the surface of Bi4Ti3O12 nanosheets. The optimized Bi4Ti3O12-BiPO4-0.5 increased the NO oxidation efficiency to 73.05%, surpassing pure Bi4Ti3O12 (63.45%) and BiPO4 (8.35%). Experiments and theoretical calculations indicated that the closely contacted heterointerface between BTO and BPO promoted the generation of the built-in electric field, which led to the formation of the Z- scheme transfer pathway for the photogenerated carriers. Therefore, the separation of photogenerated carriers was facilitated while retaining high redox potential, generating more ·O2– and ·OH to participate in NO oxidation. Furthermore, the adsorption of NO and O2 was enhanced by introducing BiPO4, further improving the photocatalytic NO oxidation performance. This work emphasizes the critical role of heterointerface in accelerating charge transfer, providing a basis for the design and construction of tightly contacted heterojunction photocatalysts.

Remarkable improvement in photocatalytic activity of g-C3N4 for NO oxidation through surface hydroxylation

The nitrogen oxide emissions originating from combustion pose significant risks to the environment. Photocatalysis is considered an efficient and environmentally friendly strategy to alleviate this problem. Graphitic carbon nitride (g-C3N4) is regarded as one of the most promising organic photocatalytic materials for environmental purification. However, its small specific surface area, weak adsorption and high recombination rate of charge carriers result in low intrinsic photocatalytic activity. To overcome these obstacles, a hydrothermal treatment of dicyandiamide-derived g-C3N4 (DCN) at different temperatures (140–200 °C) was employed to enhance the photocatalytic activity for NO oxidation. The experimental results demonstrated a significant improvement in the photocatalytic oxidation removal rate of NO after a hydrothermal treatment. The optimal photocatalyst, DCN-180, treated at 180 °C, demonstrated the highest NO removal efficiency (65.0 %), which is twice the value of pristine DCN (32.5 %). Additionally, the formation of the toxic intermediate NO2 was effectively suppressed during the reaction. Photoelectrochemical tests revealed that DCN-180 exhibited higher photocurrent density and smaller impedance radius compared to the untreated g-C3N4 sample. Moreover, density functional theory (DFT) calculations confirmed that the DCN-180 sample showed a stronger ability to adsorb O2 and NO. The enhanced photocatalytic NO oxidation performance of DCN-180 has been primarily attributed to its enlarged specific surface area (from 10.7 to 35.5 m2 g−1), local polarization effect, reduced interfacial charge transfer resistance, and improved adsorption abilities for NO and O2 molecules. This study provides valuable insights for designing and preparing highly efficient g-C3N4 based photocatalysts through surface modification for photocatalytic NO purification.

Study of pyrene-based covalent organic frameworks for efficient photocatalytic oxidation of low-concentration NO

This research presents the development of innovative pyrene-based COFs aimed at enhancing photocatalytic oxidation of low-concentration nitrogen oxide. By precisely modifying the structural length and incorporating additional functional groups into pyrene-based COFs, we identified TAPPy-DMTP-COF as the most effective performer. This COF, characterized by its shortest length and the presence of -OCH3 functional groups, demonstrated superior performance, likely due to reduced electron transfer resistance and the presence of additional oxygen active sites. Building on the potential of TAPPy-DMTP-COF, we developed a covalently linked Type-II heterostructure with g-C3N4. The resulting heterostructure, 40TAPPy-DMTP-COF/g-C3N4, with a 40 % mass fraction of TAPPy-DMTP-COF, was confirmed using SEM, XRD, and other techniques. It exhibited an exceptional photocatalytic efficiency of 45.8 % and NO3- selectivity of 97.4 %. This remarkable performance can be attributed to improved electron communication facilitated by chemical bonding, as confirmed by XPS results. Additionally, the optimized heterostructure interface not only improved electron transfer but also inhibited the recombination of electron-hole pairs. The growth of TAPPy-DMTP-COF on the surface of g-C3N4 significantly enhanced visible light absorption, as confirmed by UV–vis spectroscopy. This study not only underscores the importance of precise control over the structural features of pyrene-based COFs but also introduces a novel approach for enhancing NO oxidation. By constructing a covalently linked Type-II heterostructure, we have significantly enhanced the interface interaction within the heterostructure, leading to superior photocatalytic performance.

Efficient photocatalytic decomposition of NO and mechanism insight enabled by NaBH4-reduced N(ligancy-3)-vacancy-rich-graphitic carbon nitride

Vacancy defect engineering is an effective means to improve the performance of g-C3N4 photooxidation for NO removal. In this paper, flake graphite-phase g-C3N4 is prepared by thermal polycondensation. Then g–C3N4–x (x = 0, 0.5, 1.0, 1.5, and 2.0) containing various amounts of vacancies of nitrogen atoms with (3 coordination number) ligancy 3 (N(ligancy-3)) was prepared by NaBH4 reduction at room temperature. The introduction of N vacancies in g-C3N4 narrowed the forbidden gap, enhanced optical absorbance, optimized photo exciton separation and migration, and functioned as traps to mitigate the recombination of photogenerated electron-hole pairs. As a result, g–C3N4–x shows a superior NO removal performance, especially g–C3N4–1.5, which exhibits a high NO removal rate of 66.7 %, excellent resistance to the by-product NO2, and excellent stability. The free-radical seizure experiments and electron paramagnetic resonance (EPR) studies proved the superiority of superoxide radicals, electrons and holes as the prominent free radicals in the photocatalytic NO removal process. In situ diffuse infrared Fourier transform spectroscopy (DRIFTS) confirmed that the cis-dimer (NO)2 produced from NO adsorption on the surface of g–C3N4–1.5 is an important intermediate. Additionally, NO2− is observed as an intermediate and a primary product, and NO3− is identified as the key product of NO photocatalytic oxidation. DFT calculations showed that the N(ligancy-3) vacancy introduces impurity energy levels in g-C3N4 and shortens the electron migration path. The adsorption calculation of NO demonstrated that g–C3N4–N(ligancy-3) exhibits good adsorption and conversion of NO. This study provides a practical defect engineering for the g-C3N4 to remediate environmental pollution.

Visible light photocatalytic oxidation of NO using g-C3N4 nanosheets: stability, kinetics, and effect of humidity

Visible light photocatalytic oxidation of NO using g-C3N4 nanosheets: stability, kinetics, and effect of humidity

Enhancement of photocatalytic NO oxidation by Ag-sulfide on TiO2 mixed with Na-ZSM-5

Enhancing NO oxidation performance is pivotal for integrating photocatalysts with wet scrubbers in continuous flow systems. Despite the recent development of various catalysts, such as MOFs, our goal was to simplify the composition by using photocatalyst + zeolite catalyst, bringing us closer to a catalyst that can be practically applied. In this study, we have utilized Ag2S doping and Na-ZSM-5 mixing to improve the photocatalytic NO oxidation performance. Results showed that Ag2S doping improved visible light absorbance and NO oxidation, despite the observed fluctuations in NO conversion being attributable to mass transfer limitations. Mixing with Na-ZSM-5 compensated for the mass transfer limitations and improved its average NO conversion from 19 to 34 %. The Na-ZSM-5 increased the NO adsorption capacity considerably to 0.67 mmol g−1, which reduced the fluctuations in the catalytic performance; subsequently, the diffusion of NO led to its oxidation. Detailed analyses using NO-TPD and DRIFTS further elucidated these improvements, highlighting the significance of optimizing both oxidation reaction and mass transfer rates in the photocatalytic process. We believed that the composite of Ag2S-TiO2 + Na-ZSM-5 could simplify the ways to improve the photocatalytic NO oxidation performance and make it closer to practical applications.

An organic/inorganic Z-scheme heterojunction Yb-MOF/BiOBr for efficient photocatalytic removal of NO

The advantages of visible light-driven catalysts with good light absorption, fast charge separation rate and high redox capacity are compelling. However, conventional inorganic semiconductor, such as pure BiOBr (BOB), showed a rapid photogenerated carriers recombination rate and low solar energy utilization ability, which limited the practical application of its photocatalytic performance. In this work, a novel organic/inorganic interleaved (Z-scheme) heterojunction Yb-MOF/BiOBr (Yb-MOF/BOB) photocatalyst was successfully synthesized. Compared with a single component, the Yb-MOF/BOB heterojunction exhibited significantly enhanced performance in photocatalytic oxidation of NO under visible light. Among them, Yb-MOF/BOB-20 had the best photocatalytic NO removal effect, up to 6424 ppb/g, which was 2.8 times and 4.2 times that of BOB and Yb-MOF, respectively. Photoelectrochemical characterization confirmed that the formation of heterojunctions broadened the absorption sidebands and increased the charge transfer at the interfacial junction of Yb-MOF/BOB. Combined with UPS, ESR and in-situ DRIFTS analysis, possible photocatalytic mechanisms were revealed, in which the formation of the Yb-MOF/BOB heterostructure endowed its high charge mobility and strong redox ability. Therefore, this work provided an effective way for photocatalytic removal of NO, and offered new ideas for developing heterogeneous photocatalysts.

Boosting photocatalytic NO oxidation mediated by high redox charge carriers from visible light-driven C3N4/UiO-67 S-scheme heterojunction photocatalyst

The construction of CN/UiO-67 (CNU) S-scheme heterojunction composites through in situ formation of UiO-67 on carbon nitride (C3N4) helps to address the limitations of carbon nitride (CN) in photocatalytic NO elimination. The optimized CNU3 demonstrates superior photocatalytic efficiency, which is attributed to electronic channels constructed by Zr-N bonds and S-scheme electron transport mechanism, effectively promoting the efficient separation of photogenerated charge carriers with high redox potentials. Density Functional Theory (DFT) calculations reveal redistributed electronic orbitals in CNU3, with progressive and continuous energy levels near the Fermi level, which bolsters electronic conduction. Comprehensive quenching experiments, Electron Paramagnetic Resonance (EPR), and in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analyses highlight a synergistic interplay of electrons, holes, and superoxide radicals in CNU3, inhibiting the generation of toxic nitrogen oxide intermediates and culminating in highly efficient photocatalytic NO oxidation. This study not only elucidates the mechanisms underpinning the enhanced performance of CNU3 heterojunctions but also offers new perspectives on the preparation and interfacial charge separation of heterojunction photocatalysts.

Remarkable Enhancement of Photocatalytic Activity of High-Energy TiO2 Nanocrystals for NO Oxidation through Surface Defluorination.

The superior photocatalytic activity of TiO2 nanocrystals with exposed high-energy (001) facets, achieved through the use of hydrofluoric acid as a shape-directing reagent, is widely reported. However, in this study, we report for the first time the detrimental effect of surface fluorination on the photoreactivity of high-energy faceted TiO2 nanocrystals towards NO oxidation (resulting in a NO removal rate of only 5.9%). This study aims to overcome this limitation by exploring surface defluorination as an effective strategy to enhance the photocatalytic oxidation of NO on TiO2 nanocrystals enclosed with (001) facets. We found that surface defluorination, achieved through either NaOH washing (resulting in an improved NO removal rate of 23.2%) or calcination (yielding an enhanced NO removal rate of 52%), leads to a large increase in the photocatalytic oxidation of NO on TiO2 nanocrystals with enclosed (001) facets. Defluorination processes stimulate charge separation, effectively retarding recombination and significantly promoting the production of reactive oxygen species, including superoxide radicals (·O2-), singlet oxygen (1O2), and hydroxyl radicals (·OH). Both in situ diffuse reflectance infrared Fourier-transform spectroscopy and density functional theory calculations confirm the higher adsorption of NO after defluorination, thus facilitating the oxidation of NO on TiO2 nanocrystals.

Atomically dispersed Mn sites on TiO2(B) microspheres enables efficient photocatalytic abatement of NOx

While photocatalytic technology has been recognized as an effective means for removing low-concentration NOx in ambient atmosphere, it still faces the challenge of the deep oxidation in high efficiency. In many cases, the release of more toxic NO2 byproduct appeared to be inevitable during the photocatalytic oxidation of NO. Herein we report that the atomically dispersed MnOx cocatalyst on TiO2(B) microspheres could significantly enhance the deep oxidation of NOx under mild photocatalytic conditions (1 mW/cm2 UV-A light, 1 L/min flow rate). At an initial NO concentration of 0.35 ppm, ca. 67.15% of NO is oxidized on the MT-0.5 sample, which is 2.76 times higher than the pristine TiO2(B) sample. More importantly, the release of NO2 is suppressed by 2.11 times. Comprehensive spectral analyses suggest that atomically dispersed MnOx effectively promotes the charge separation of photogenerated carriers in TiO2(B), even better than MnOx nanoparticles-loaded TiO2(B). EPR and in-situ FTIR analyses illustrate that atomically dispersed MnOx-loaded TiO2(B) sample exhibits excellent low concentration NOx abatement performance, thus providing a rational mechanism for the NO deep oxidation pathway. This study not only provides a unique approach for preparing non-noble metal atomically dispersed co-catalysts, but also affords an effective means for efficient photocatalytic NO degradation.

Ligand-induced reaction mechanism regulation on Sr/Nb2O5 for high-efficiency selective photocatalytic NO oxidation

Developing highly efficient photocatalysts that selectively convert NO pollutants to NO3¯ while storing metabolic nitrogen for crops remains a great challenge. Simultaneously, there is a dearth of research investigating the relationship between the chemical environment and the activity of catalytic sites. Herein, an efficient impregnation approach to access atomically dispersed Sr single atoms supported on Nb2O5 is reported; meanwhile, various ligands (-Cl, -Br, -OH) are employed to customize the local structure. The results show that Cl-Sr/Nb2O5 exhibits excellent catalytic performance in eliminating NO, which is significantly superior to other catalysts. The introduction of Sr atom and ligand increases the energy barrier of NO2 formation, thus improving the selectivity of converting NO to NO3¯. This study highlights the importance of precisely designing the catalytic site at the atomic level, and the obtained insights may serve as a valuable guide for developing future catalyst designs.

Promoting the photocatalytic NO oxidation activity of hierarchical porous g-C3N4 by introduction of nitrogen vacancies and charge channels

Sluggish charge kinetics and moderate adsorption–desorption ability of gas molecules are major limitations for photocatalytic NOx elimination of bulk g-C3N4. A hierarchical porous g-C3N4 photocatalyst modified with N vacancies and charge channels (KCNN) was prepared by thermal polymerisation in KCl medium followed by quenching to increase the photocatalytic efficiency. The optimized KCNN sample exhibits highly enhanced photocatalytic NO removal rate (70.5%), which is superior to those of bulk g-C3N4 (38.1%), porous g-C3N4 (54.5%) and K-doped g-C3N4 (58.6%), respectively. X-ray photoelectron spectroscopy and electron paramagnetic resonance data reveal the successful formation of N vacancy in g-C3N4 framework. The enhanced activity of KCNN is ascribed to the enlarged surface area, expanded light absorption, low charge recombination efficiency and strong oxidation capability, respectively. In situ DRIFTS and density functional theory results suggest that the introduction of N vacancies and K+ ions enable control over NO adsorption and activation, leading to the implementation of a preferred pathway (NO → NO+ → NO3‾) and reduction in the emission of toxic intermediates. This work presents a potential idea for improving the charge transfer of layered materials and optimising the diffusion/adsorption/activation of gas molecules for photocatalytic NO oxidation.

Carbon layer derived carrier transport in Co/g-C3N4 nanosheet junctions for efficient H2O2 production and NO removal

Co nanoparticles are embedded in N-doped carbon nanotubes (Co-N-carbon nanotubes) using combinations of mechano-chemical pre-treatment and thermal polymerization process (at 760 °C). A further thermal polymerization process done on these Co-N-carbon nanotubes and ultrathin graphitic carbon nitrate (g-C3N4) leads to the formation of Co nanoparticles (coated with carbon layers) embedded g-C3N4 nanosheets composite, along with the disappearance of carbon nanotube morphology on the material. The Co/g-C3N4 junctions are constructed with a Schottky barrier formed between the carbon layer coated Co nanoparticles and the g-C3N4 nanosheets. The presence of carbon layers in the composite system facilitates transport of photogenerated electrons at the Fermi level of Co, which results in enhanced photocatalytic H2O2 generation and NO oxidation performances of the composite material in visible light irradiation condition with excellent cyclic stability. The Schottky junction composites constructed using optimized preparation conditions in case of no co-catalyst incorporation shows a photocatalytic H2O2 generation efficiency of 3618 μmolL−1h−1 which is about 1000 times of that of pristine g-C3N4 nanosheets. A NO removal rate of 62 % (higher than that of the commercial P25 (TiO2)) is also observed. These results provide possible approaches on constructing advanced photocatalysts for energy and environmental applications.

Triangle Cl-Ag1-Cl Sites for Superior Photocatalytic Molecular Oxygen Activation and NO Oxidation of BiOCl.

BiOCl photocatalysis shows great promise for molecular oxygen activation and NO oxidation, but its selective transformation of NO to immobilized nitrate without toxic NO2 emission is still a great challenge, because of uncontrollable reaction intermediates and pathways. In this study, we demonstrate that the introduction of triangle Cl-Ag1-Cl sites on a Cl-terminated, (001) facet-exposed BiOCl can selectively promote one-electron activation of reactant molecular oxygen to intermediate superoxide radicals (•O2-), and also shift the adsorption configuration of product NO3- from the weak monodentate binding mode to a strong bidentate mode to avoid unfavorable photolysis. By simultaneously tuning intermediates and products, the Cl-Ag1-Cl-landen BiOCl achieved > 90% NO conversion to favorable NO3- of high selectivity (> 97%) in 10 min under visible light, with the undesired NO2 concentration below 20 ppb. Both the activity and the selectivity of Cl-Ag1-Cl sites surpass those of BiOCl surface sites (38% NO conversion, 67% NO3- selectivity) or control O-Ag1-O sites on a benchmark photocatalyst P25 (67% NO conversion and 87% NO3- selectivity). This study develops new single-atom sites for the performance enhancement of semiconductor photocatalysts, and also provides a facile pathway to manipulate the reactive oxygen species production for efficient pollutant removal.

Triangle Cl−Ag1−Cl Sites for Superior Photocatalytic Molecular Oxygen Activation and NO Oxidation of BiOCl

AbstractBiOCl photocatalysis shows great promise for molecular oxygen activation and NO oxidation, but its selective transformation of NO to immobilized nitrate without toxic NO2 emission is still a great challenge, because of uncontrollable reaction intermediates and pathways. In this study, we demonstrate that the introduction of triangle Cl−Ag1−Cl sites on a Cl‐terminated, (001) facet‐exposed BiOCl can selectively promote one‐electron activation of reactant molecular oxygen to intermediate superoxide radicals (⋅O2−), and also shift the adsorption configuration of product NO3− from the weak monodentate binding mode to a strong bidentate mode to avoid unfavorable photolysis. By simultaneously tuning intermediates and products, the Cl−Ag1−Cl‐landen BiOCl achieved >90 % NO conversion to favorable NO3− of high selectivity (>97 %) in 10 min under visible light, with the undesired NO2 concentration below 20 ppb. Both the activity and the selectivity of Cl−Ag1−Cl sites surpass those of BiOCl surface sites (38 % NO conversion, 67 % NO3− selectivity) or control O−Ag1−O sites on a benchmark photocatalyst P25 (67 % NO conversion and 87 % NO3− selectivity). This study develops new single‐atom sites for the performance enhancement of semiconductor photocatalysts, and also provides a facile pathway to manipulate the reactive oxygen species production for efficient pollutant removal.

Facile synthesis of multi-layer Co(OH)2/CeO2-g-C3N4 ternary synergistic heterostructure for efficient photocatalytic oxidation of NO under visible light

In this work, we report a one-step synthesis of ternary Z-scheme Co(OH)2/CeO2-g-C3N4 (CoCe-CN) heterostructure via hydrothermal method. Owing to the modification of Co(OH)2 and CeO2, the existence of Co(OH)2 as an electron acceptor-donor center between CeO2 and g-C3N4 accelerates the electron transfer and provides extra OH- reaction pathway for photocatalytic oxidation of NO. As a result, 50CoCe-CN (Co and Ce accounting for 25% mass ratio separately) achieved a 53.5% conversion efficiency of NO at 600 ppb concentration, which is 1.82 times that of g-C3N4 under visible light. The results of the DFT analysis and element distribution of cobalt and ceria provide convincing evidence supporting the existence of a novel multi-layer structure in the CoCe-CN photocatalyst. This structure involves the loading of CeO2 and Co(OH)2 on the g-C3N4 surface, and Co(OH)2 as a co-catalyst introduced between CeO2 and g-C3N4 realizes the synergy between CeO2 and Co(OH)2 which further improve the photocatalytic properties. The higher photocatalytic efficiencies observed in the CoCe-CN photocatalysts compared to those containing only cobalt (Co-CN) or ceria (Ce-CN) provide further evidence of the synergistic effect of these two elements. This work demonstrates a more efficient and effective ternary photocatalytic system, with greater practical potential for photocatalytic oxidation of NO.