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Chinese Journal of Catalysis
2021, Vol. 42, No. 3
Online: 18 March 2021

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Cover: Chen and coworkers in their article pages 367–375 reported the structure changes of supported Cu/Al₂O₃, Cu/ZnO and Cu/ZnO/Al₂O₃ catalysts and surface species during H₂ reduction and CO₂ hydrogenation observed using in situ FTIR, ex situ XPS and HS-LEIS. The synergistic effects of Al₂O₃ and ZnO in CuZnAlO catalysts have been revealed, and the active sites have been proposed to be Cu⁰, Cu⁺, and adjacent highly defective ZnOx overlayer.

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In situ FTIR and ex situ XPS/HS-LEIS study of supported Cu/Al2O3 and Cu/ZnO catalysts for CO2 hydrogenation Jun Hu, Yangyang Li, Yanping Zhen, Mingshu Chen, Huilin Wan 2021, 42 (3):  367-375.  DOI: 10.1016/S1872-2067(20)63672-5 Abstract ( 576 )   HTML ( 278 )   PDF (885KB) ( 504 )   Supporting Information Cu-based catalysts are commonly used in industry for methanol synthesis. In this study,supported catalysts of 5 wt% Cu/Al2O3 and 5 wt% Cu/ZnO were prepared,and their surface characteristics during H2 reduction and CO2 hydrogenation were investigated using in situ Fourier transform infrared spectroscopy (FTIR),ex situ X-ray photoelectron spectroscopy,and high sensitivity low energy ion scattering spectroscopy. During the H2 reduction and CO2 hydrogenation processes,it was found that Al2O3 can stabilize Cu+. In situ FTIR spectra indicated that the 5 wt% Cu/Al2O3 can adsorb large amounts of bicarbonate and carbonate species,which then convert into formate during CO2 hydrogenation. For the 5 wt% Cu/ZnO,it was found that Cu nanoparticles were gradually covered by a highly defective ZnOx overlayer during H2 reduction,which can effectively dissociate H2. During CO2 hydrogenation,the adsorbed bicarbonate or carbonate species can convert into formate and then into a methoxy species. Using these surface sensitive methods,a more in-depth understanding of the synergistic effect among the Cu,Al2O3,and ZnO components of Cu-based catalysts was achieved.

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Electron-induced rapid crosslinking in supramolecular metal-peptide assembly and chemically responsive disaggregation for catalytic application Zongyuan Wang, Jiajun Wang, Zeyu Sun, Wenlong Xiang, Chenyang Shen, Ning Rui, Mingzhu Ding, Yingjin Yuan, Honggang Cui, Chang-jun Liu 2021, 42 (3):  376-387.  DOI: 10.1016/S1872-2067(20)63655-5 Abstract ( 218 )   HTML ( 8 )   PDF (3434KB) ( 349 )   Supporting Information The applications of supramolecular metal-peptide assemblies as catalyst or catalyst precursor have recent attracted increasing attentions. In this work,a fragment of the amyloid β-peptide,NH2-KLVFF-COOH,was assembled into nanofilms with encapsulated Pd,Pt and Au nanoparticles (NPs) via a one-step room temperature electron induction method. The effects of building block,intermolecular interaction,driving force and side-chain on the assembly were investigated. The assembly mechanism was thereby proposed. The crosslinking of peptide monomers results in mainly random and unordered structures. The obtained metal-peptide assemblies are extremely stable in water at neutral pH for long term. However,the metal NPs are able to be responsively released under basic and reductive conditions. The released NPs show a high activity to catalyze the reduction of 4-nitrophenol. The present studies on assembly mechanism and responsive release will be helpful for the design of organic skeletons and also for the future development of peptide stabilized metallic NPs with applications beyond catalysts.

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Highly dispersed boron-nitride/CuOx-supported Au nanoparticles for catalytic CO oxidation at low temperatures Fan Wu, Lei He, Wen-Cui Li, Rao Lu, Yang Wang, An-Hui Lu 2021, 42 (3):  388-395.  DOI: 10.1016/S1872-2067(20)63669-5 Abstract ( 210 )   HTML ( 14 )   PDF (2894KB) ( 359 )   Supporting Information Supported-Au catalysts show excellent activity in CO oxidation,where the nature of the support has a significant impact on catalytic activity. In this work,a hexagonal boron nitride (BN) support with a high surface area and adequately exposed edges was obtained by the ball-milling technique. Thereafter,impregnation of the BN support with Cu(NO3)2 followed by calcination under air at 400 °C yielded a CuO-modified support. After Au loading,the obtained Au-CuOx/BN catalyst exhibited high CO oxidation activity at low temperatures with a 50% CO conversion temperature (T50%) of 25 °C and a complete CO conversion temperature (T100%) of 80 °C,well within the operational temperature range of proton exchange membrane fuel cells. However,the CO oxidation activity of Au/BN,prepared without CuOx for comparison,was found to be relatively low. Our study reveals that BN alone disperses both Cu and Au nanoparticles well. However,Au nanoparticles on the surface of BN in the absence of CuO species tend to aggregate upon CO oxidation reactions. Conversely,Au nanoparticles supported on the surface of CuO-modified BN remain small with an average size of ~2.0 nm before and after CO oxidation. Moreover,electron transfer between Au and Cu species possibly favors the stabilization of highly dispersed Au nanoparticles on the BN surface and also enhances CO adsorption. Thus,our results demonstrate that thermally stable and conductive CuO-modified BN is an excellent support for the preparation of highly dispersed and stable Au catalysts.

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Stable CuO/La2Sn2O7 catalysts for soot combustion: Study on the monolayer dispersion behavior of CuO over a La2Sn2O7 pyrochlore support Xiaohui Feng, Rui Liu, Xianglan Xu, Yunyan Tong, Shijing Zhang, Jiacheng He, Junwei Xu, Xiuzhong Fang, Xiang Wang 2021, 42 (3):  396-408.  DOI: 10.1016/S1872-2067(20)63657-9 Abstract ( 159 )   HTML ( 5 )   PDF (2057KB) ( 278 )   Supporting Information To understand the dispersion behavior of metal oxides on composite oxide supports and with the expectation of developing more feasible catalysts for soot oxidation,CuO/La2Sn2O7 samples containing varied CuO loadings were fabricated and characterized by different techniques and density functional theory calculations. In these catalysts,a spontaneous dispersion of CuO on the La2Sn2O7 pyrochlore support formed,having a monolayer dispersion capacity of 1.90 mmol CuO/100 m2 La2Sn2O7 surface. When loaded below this capacity,CuO exists in a sub-monolayer or monolayer state. X-ray photoelectron spectroscopy (XPS),Raman spectroscopy,and Bader charge and density of states analyses indicate that there are strong interactions between the sub-monolayer/monolayer CuO and the La2Sn2O7 support,mainly through the donation of electrons from Cu to Sn at the B-sites of the structure. In contrast,Cu has negligible interactions with La at the A-sites. This suggests that,in composite oxide supports containing multiple metals,the supported metal oxide interacts preferentially with one kind of metal cation in the support. The Raman,in situ diffuse reflectance infrared Fourier transform spectroscopy,and XPS results confirmed the formation of both O2- and O22- as the active sites on the surfaces of the CuO/La2Sn2O7 catalysts,and the concentration of these active species determines the soot combustion activity. The number of active oxygen anions increased with increase in CuO loading until the monolayer dispersion capacity was reached. Above the monolayer dispersion capacity,microsized CuO crystallites formed,and these had a negative effect on the generation of active surface oxygen sites. In summary,a highly active catalyst can be prepared by covering the surface of the La2Sn2O7 support with a CuO monolayer.

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Efficient visible light initiated hydrothiolations of alkenes/alkynes over Ir2S3/ZnIn2S4: Role of Ir2S3 Xinglin Wang, Yuanyuan Li, Zhaohui Li 2021, 42 (3):  409-416.  DOI: 10.1016/S1872-2067(20)63660-9 Abstract ( 142 )   HTML ( 8 )   PDF (991KB) ( 297 )   Supporting Information Research Institute of Photocatalysis,State Key Laboratory of Photocatalysis on Energy and Environment,College of Chemistry,Fuzhou University,Fuzhou 350116,Fujian,ChinaArticle history:The hydrothiolations of alkynes/alkenes with thiols is an atom-economic and thus attractive method for the constructions of C-S bonds. Here Ir2S3/ZnIn2S4 nanocomposites with varied Ir2S3 loadings were obtained by one-pot solvothermal method from ZnCl2,InCl3 and thioacetamide with IrCl3. The loading of Ir2S3 on the surface of ZnIn2S4 promoted the hydrothiolations of alkenes and alkynes,with an optimum performance observed over 0.5 mol% Ir2S3/ZnIn2S4 nanocomposite. Based on the studies on the performance of several other cocatalysts (MoS2,NiS and Pd) loaded ZnIn2S4 and the EIS analyses,it was proposed that the superior performance over Ir2S3/ZnIn2S4 nanocomposite can be ascribed to an improved efficiency on the photogeneration of the thiyl radicals by loading Ir2S3 as well as its inactivity for photocatalytic hydrogen evolution,a side reaction in the light initiated hydrothiolation reaction over ZnIn2S4. This study not only demonstrates an efficient and green strategy to synthesize thiolated products under visible light based on semiconductor photocatalysis,but also provides some guidances for the design and development of photocatalytic systems for light induced organic syntheses.

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Comprehensive understanding of the superior performance of Sm-modified Fe2O3 catalysts with regard to NO conversion and H2O/SO2 resistance in the NH3-SCR reaction Chuanzhi Sun, Wei Chen, Xuanxuan Jia, Annai Liu, Fei Gao, Shuai Feng, Lin Dong 2021, 42 (3):  417-430.  DOI: 10.1016/S1872-2067(20)63666-X Abstract ( 213 )   HTML ( 14 )   PDF (7006KB) ( 559 )   Supporting Information Abstract:Sm-doped Fe2O3 catalysts,with a homogeneous distribution of Sm in Fe2O3 nanoparticles,were synthesized using a citric acid-assisted sol-gel method. Kinetic studies show that the reaction rate for NOx reduction using the optimal catalyst (0.06 mol% doping of Sm in Fe2O3) was nearly 11 times higher than that for pure Fe2O3,when calculated based on specific surface area. Furthermore,the Fe0.94Sm0.06Ox catalyst maintains > 83% NOx conversion for 168 h at a high space velocity in the presence of SO2 and H2O at 250 °C. A substantial amount of surface-adsorbed oxygen was generated on the surface of Fe0.94Sm0.06Ox,which promoted NO oxidation and the subsequent fast reaction between NOx and NH3. The adsorption and activation of NH3 was also enhanced by Sm doping. In addition,Sm doping facilitated the decomposition of NH4HSO4 on the surface of Fe0.94Sm0.06Ox,resulting in its high activity and stability in the presence of SO2 + H2O.

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Hierarchical CoSeS nanostructures assisted by Nb doping for enhanced hydrogen evolution reaction Ya-Nan Zhou, Yu-Ran Zhu, Xin-Tong Yan, Yu-Ning Cao, Jia Li, Bin Dong, Min Yang, Qing-Zhong Li, Chen-Guang Liu, Yong-Ming Chai 2021, 42 (3):  431-438.  DOI: 10.1016/S1872-2067(20)63673-7 Abstract ( 236 )   HTML ( 8 )   PDF (2607KB) ( 445 )   Supporting Information Metal doping for active sites exhibits remarkable potential for improving the hydrogen evolution reaction (HER). Multi-doping and the use of a conductive substrate can further modulate catalytic performance. Herein,Nb-CoSe well dispersed in N-doped carbon nanospheres (NCs,Nb-CoSe@NC) was synthesized to serve as a conductive substrate and facilitated good dispersion of active sites for the HER. Nb doping can also change the electronic structure of CoSe,which facilitates the activity for the HER. In order to further improve the conductivity and intrinsic activity of Nb-CoSe@NC,dual,nonmetal doping was realized through gas sulfurization to prepare hierarchical Nb-CoSeS@NC. The prepared Nb-CoSeS@NC,with a core-shell structure,exhibited a low overpotential of 115 mV at 10 mA cm-2,which is smaller than that of the most doped catalysts. In addition,NCs not only improved the dispersion and conductivity of the catalyst but also prevented metal corrosion in an electrolyte,thus facilitating the long-term stability of Nb-CoSeS@NC. Moreover,the synergistic effect of the multi-doping of Nb,S,and Se was explained. This work provides a promising,multi-doping strategy for the large-scale application of transition-metal-based electrocatalysts for the HER.

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Coralline-like Ni2P decorated novel tetrapod-bundle Cd0.9Zn0.1S ZB/WZ homojunctions for highly efficient visible-light photocatalytic hydrogen evolution Zhuwang Shao, Xiao Meng, Hong Lai, Dafeng Zhang, Xipeng Pu, Changhua Su, Hong Li, Xiaozhen Ren, Yanling Geng 2021, 42 (3):  439-449.  DOI: 10.1016/S1872-2067(20)63597-5 Abstract ( 180 )   HTML ( 10 )   PDF (2720KB) ( 442 )   Supporting Information In this study,Ni2P-Cd0.9Zn0.1S (NPCZS) composites were synthesized by coupling tetrapod bundle Cd0.9Zn0.1S (CZS) and coralline-like Ni2P (NP) via a simple calcination method. CZS shows outstanding activity in photocatalytic hydrogen evolution (1.31 mmol h-1),owing to its unique morphology and heterophase homojunctions (ZB/WZ),which accelerate the separation and transfer of photogenerated charges. After coupling with NP,the photoactivity of NPCZS was enhanced,and the maximum hydrogen evolution rate of 1.88 mmol h-1 was reached at a NP content of 12 wt%,which was 1.43 times higher than that of pure CZS. The experimental results of the photocatalytic activity,viz. photoluminescence spectra,surface photovoltage spectra,and electrochemical test showed that the enhanced photoactivity of NPCZS should be attributed to the synergistic effects of the novel tetrapod-bundle morphology,heterophase homojunctions,and decoration of the NP co-catalyst. Moreover,the as-prepared NPCZS composites exhibited excellent photostability and recyclability. Herein,we propose a possible mechanism for the enhanced photocatalytic activity.

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Sulfur promoted n-π* electron transitions in thiophene-doped g-C3N4 for enhanced photocatalytic activity Feiyue Ge, Shuquan Huang, Jia Yan, Liquan Jing, Feng Chen, Meng Xie, Yuanguo Xu, Hui Xu, Huaming Li 2021, 42 (3):  450-459.  DOI: 10.1016/S1872-2067(20)63674-9 Abstract ( 285 )   HTML ( 16 )   PDF (2459KB) ( 416 )   Supporting Information Expanding the optical absorption range of photocatalysts is still a key endeavor in graphitic carbon nitride (g-C3N4) studies. Here,we report on a novel thiophene group extending the optical property,which is assigned to n-π* electronic transitions involving the two lone pairs on sulfur (TLPS). The as-prepared samples,denoted as CN-ThAx (where x indicates the amount of ThA added,mg),showed an additional absorption above 500 nm as compared to pristine g-C3N4. Further,the thiophene group enhanced charge carrier separation to suppress e-/h+ pair recombination. The experimental results suggest that the thiophene group can obstruct the polymerization of melem to generate a large plane,thus exposing the lone electron pairs on the sulfur. The photocatalytic activity was evaluated in the decomposition of bisphenol A and H2 evolution. Compared with g-C3N4,the optimized CN-ThA30 sample led to a 6.6- and 2-fold enhancement of the degradation and H2 generation rates,respectively. The CN-ThA30 sample allowed for synchronous H2 production and BPA decomposition.

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Tuning the O-O bond formation pathways of molecular water oxidation catalysts on electrode surfaces via second coordination sphere engineering Qiming Zhuo, Shaoqi Zhan, Lele Duan, Chang Liu, Xiujuan Wu, Mårten S. G. Ahlquist, Fusheng Li, Licheng Sun 2021, 42 (3):  460-469.  DOI: 10.1016/S1872-2067(20)63671-3 Abstract ( 222 )   HTML ( 8 )   PDF (868KB) ( 385 )   Supporting Information A molecular [Ru(bda)]-type (bda = 2,2’-bipyridine-6,6’-dicarboxylate) water oxidation catalyst with 4-vinylpyridine as the axial ligand (Complex 1) was immobilized or co-immobilized with 1-(trifluoromethyl)-4-vinylbenzene (3F) or styrene (St) blocking units on the surface of glassy carbon (GC) electrodes by electrochemical polymerization,in order to prepare the corresponding poly-1@GC,poly-1+P3F@GC,and poly-1+PSt@GC functional electrodes. Kinetic measurements of the electrode surface reaction revealed that [Ru(bda)] triggers the O-O bond formation via (1) the radical coupling interaction between the two metallo-oxyl radicals (I2M) in the homo-coupling polymer (poly-1),and (2) the water nucleophilic attack (WNA) pathway in poly-1+P3F and poly-1+PSt copolymers. The comparison of the three electrodes revealed that the second coordination sphere of the water oxidation catalysts plays vital roles in stabilizing their reaction intermediates,tuning the O-O bond formation pathways and improving the water oxidation reaction kinetics without changing the first coordination structures.

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Producing of cinnamyl alcohol from cinnamaldehyde over supported gold nanocatalyst Yuan Tan, Xiaoyan Liu, Leilei Zhang, Fei Liu, Aiqin Wang, Tao Zhang 2021, 42 (3):  470-481.  DOI: 10.1016/S1872-2067(20)63678-6 Abstract ( 305 )   HTML ( 14 )   PDF (1645KB) ( 440 )   Chemoselective hydrogenation of unsaturated aldehyde to unsaturated alcohol has attracted growing interests in recent years due to its widespread applications in fine chemicals. However,the hydrogenation of the C=O bond was thermodynamically and kinetically unfavorable over the hydrogenation of the C=C bond. Thus,to obtain the unsaturated alcohol from the unsaturated aldehyde is very difficult in most of the catalytic systems. In this work,ZnAl-hydrotalcite-supported cysteine-capped Au25 nanoclusters were used as the precatalysts for chemoselective hydrogenation of cinnamaldehyde to cinnamyl alcohol. The catalyst showed stable high selectivity (~ 95%) at prolonged reaction time and complete conversion of the substrate. According to the results of the control experiments,the in-situ DRIFTS of the substrate under high pressure of hydrogen and the 27Al MAS-NMR spectroscopy,we proposed that the difference of the preferential adsorption of the C=O bond to that of the C=C bond was derived from the nature of the support of the gold catalysts.

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Facilitating active species by decorating CeO2 on Ni3S2 nanosheets for efficient water oxidation electrocatalysis Qian Wu, Qingping Gao, Limei Sun, Huanmei Guo, Xishi Tai, Dan Li, Li Liu, Chongyi Ling, Xuping Sun 2021, 42 (3):  482-489.  DOI: 10.1016/S1872-2067(20)63663-4 Abstract ( 221 )   HTML ( 9 )   PDF (1461KB) ( 536 )   Supporting Information In the pursuit of stable,high performance Ni-based oxygen evolution reaction (OER) electrocatalysts,modifying the local chemical compositions or fabricating hybrid nanostructures to generate abundant interfaces for improving the water oxidation activity of electrocatalysts has emerged as an effective strategy. Herein,we report the facile development of a Ni3S2-CeO2 hybrid nanostructure via an electrodeposition method. Benefiting from the strong interfacial interaction between Ni3S2 and CeO2,the electron transfer is notably improved and the water oxidation activity of Ni3S2 nanosheets is significantly enhanced. In 1.0 M KOH,the Ni3S2-CeO2 electrocatalyst achieves a current density of 20 mA cm-2 at a low overpotential of 264 mV,which is 92 mV lower than that of Ni3S2. Moreover,Ni3S2-CeO2 exhibits superior electrochemical stability. Density functional theory calculations demonstrate that the enhanced OER electrocatalytic performance of Ni3S2-CeO2 can be ascribed to an increase in the binding strength of the reaction intermediates at the Ni3S2-CeO2 interface.

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3D-ordered macroporous N-doped carbon encapsulating Fe-N alloy derived from a single-source metal-organic framework for superior oxygen reduction reaction Ya-Ru Lv, Xue-Jing Zhai, Shan Wang, Hong Xu, Rui Wang, Shuang-Quan Zang 2021, 42 (3):  490-500.  DOI: 10.1016/S1872-2067(20)63667-1 Abstract ( 530 )   HTML ( 20 )   PDF (1920KB) ( 428 )   Supporting Information Fe-N compounds with excellent electrocatalytic oxygen reduction activity are considered to be one of the most promising non-precious metal materials for fuel cells. Fe-N compounds with excellent electrocatalytic oxygen reduction activity are considered to be one of the most promising non-precious metal materials for fuel cells,which focuses on the Fe-N4 single-atom catalysts and the iron nitride materials (such as Fe2N and Fe3N). A hybridized catalyst having a hierarchical porous structure with regular macropores could enable the desired mass transfer efficiency in the catalytic process. In this study,we have constructed a new type of hybrid catalyst having iron and iron-nitrogen alloy nanoparticles (Fe-N austenite,termed as Fe-NA) embedded in the three-dimensional ordered macroporous N-doped carbon (3DOM Fe/Fe-NA@NC) by direct pyrolysis of single-source dicyandiamide-based iron metal-organic frameworks. The as-synthesized composites preserve the hierarchical porous carbon framework with ordered macropores and high specific surface area,incorporating the uniformly dispersed iron/iron-nitrogen austenite nanoparticles. Thereby,the striking architectural configuration embedded with highly active catalytic species delivers a superior oxygen reduction activity with a half-wave potential of 0.88 V and a subsequent superior Zn-air battery performance with high open-circuit voltage and continuous stability as compared to those using a commercial 20% Pt/C catalyst.

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Design of p-n homojunctions in metal-free carbon nitride photocatalyst for overall water splitting Gang Zhao, Shuhua Hao, Jinghua Guo, Yupeng Xing, Lei Zhang, Xijin Xu 2021, 42 (3):  501-509.  DOI: 10.1016/S1872-2067(20)63670-1 Abstract ( 167 )   HTML ( 15 )   PDF (1668KB) ( 614 )   Supporting Information Two-dimensional (2D) carbon nitride (CN) photocatalysts are attracting extensive attention owing to their excellent photocatalytic properties. In this study,we successfully prepared CN materials with heterogeneous structures via hydrothermal treatment,high-temperature roasting,ball milling,sintering,and other processes. Benefitting from interface interactions in hybrid architectures,the CN photocatalysts exhibited high photocatalytic activity. The rate of hydrogen production using these CN photocatalysts reached 17028.82 μmol h-1 g-1,and the apparent quantum efficiency was 11.2% at 420 nm. The ns-level time-resolved photoluminescence (PL) spectra provided information about the time-averaged lifetime of fluorescence charge carriers; the lifetime of the charge carriers causing the fluorescence of CN reached 9.99 ns. Significantly,the CN photocatalysts displayed satisfactory results in overall water splitting without the addition of sacrificial agents. The average hydrogen and oxygen production rates were 270.95 μmol h-1 g-1 and 115.21 μmol h-1 g-1 in 7 h,respectively,which were promising results for the applications of the catalysts in overall water splitting processes. We investigated the high efficiency of the prepared CN photocatalysts via a series of tests (UV-vis diffuse reflectance spectroscopy,photocurrent response measurements,PL emission spectroscopy,time-resolved PL spectroscopy,and Brunauer-Emmett-Teller analysis). Furthermore,the Mott-Schottky plot and current-voltage curve were acquired via electrochemical tests. The fabricated CN photocatalyst had a small p-n junction in its heterogeneous structure,which further enhanced its photocatalytic efficiency. Therefore,this work can promote the development of CN photocatalysts.