The porous TiO2/pg-C3N4 composite photocatalyst was successfully prepared by combining ultrasonic with hydrothermal treatment. XRD, SEM, TEM, UV-Vis DRS and PL were applied to analyze its morphology, structure and optical properties. The photocatalytic activities of the as-prepared samples were evaluated by degradating the simulated pollutants (RhB, MO) in aqueous solution under simulated sunlighti llumination. The result showed that the TiO2/pg-C3N4 (5:100) exhibited the best photocatalytic degradation performance among all photocatalists with different compositions. The photocatalytic degradation pathway of RhB was chromophore cleavage caused by O2- and h+. The improved photocatalytic performance of TiO2/pg-C3N4 (5:100) was attributed to the fact that the active sites of the photocatalytic reaction were increased due to the porous structure, on the one hand, and a Z-scheme type heterojunction was formed between TiO2 and pg-C3N4 on the other hand, which not only can increase the separation efficiency of electron-hole pairs, but also can retain the stronger reducibility of photo-generated electrons on the more negative CB of pg-C3N4 and higher oxidationability of photo-generated holes on the more positive VB of TiO2, compared with the conventional type II heterojunction.
Wang X C, Maeda K, Thomas A, et al. A metal-free polymeric photocatalyst for hydrogen production from water under visible light[J]. Nature Materials, 2009,8(1):76-80.
Ong W J, Tan L L, Ng Y H, et al. Graphitic carbon nitride (g-C3N4)-based photocatalysts for artificial photosynthesisand environmental remediation:Are we a step closer to achieving sustainability[J]? Chemical Reviews, 2016,116(12):7159-7329.
齐菲,孙迎雪,常学明,等.石墨相氮化碳光催化灭活水中多重耐药菌研究[J]. 中国环境科学, 2018,38(10):3767-3774. Qi F, Sun Y X, Chang X M, et al. Graphite carbon nitride (g-C3N4) photocatalytic disinfection on a multidrug resistant E. coli strain from secondary effluent[J]. China Environmental Science, 2018,38(10):3767-3774.
王盈霏,王枫亮,黎杰华,等.介孔氮化碳光催化降解诺氟沙星的动力学机制[J]. 中国环境科学, 2018,38(4):1346-1355. Wang Y F, Wang F L, Li J H, et al. Photocatalytic degradation kinetics and mechanism of norfloxacinusing mesoporous g-C3N4 under visible-light irradiation[J]. China Environmental Science, 2018, 38(4):1346-1355.
尹竞,廖高祖,朱冬韵,等.g-C3N4/石墨烯复合材料的制备及光催化活性的研究[J]. 中国环境科学, 2016,36(3):735-740. Yin J, Liao G Z, Zhu D Y, et al. Preparation and photocatalytic activity of g-C3N4/rGOcomposite[J]. China Environmental Science, 2016, 36(3):735-740.
张金水,王博,王心晨.氮化碳聚合物半导体光催化[J]. 化学进展, 2014,26(1):19-29. Zhang J S, Wang B, Wang X C. Carbon nitride polymeric semiconductor for photocatalysis[J]. ProgressIn Chemistry, 2014, 26(1):19-29.
Mamba G, Mishra A K. Graphitic carbon nitride (g-C3N4) nanocomposites:A new and exciting generation of visible light driven photocatalysts for environmental pollution remediation[J]. Applied Catalysis B:Environmental, 2016,198:347-377.
Zhang YJ, Thomas A, Antonietti M, et al. Activation of carbon nitride solids by protonation:Morphology changes, enhanced ionic conductivity, and photoconduction experiments[J]. Journal of the American Chemical Society, 2009,131(1):50-51.
Ma Y, Wang X L, Jia YS, et al. Titanium dioxide-based nanomaterials for photocatalytic fuel generations[J]. Chemical Reviews, 2014, 114(19):9987-10043.
Hao R R, Wang G H, Tang H, et al. Template-free preparation of macro/mesoporous g-C3N4/TiO2 heterojunction photocatalysts with enhanced visible light photocatalytic activity[J]. Applied Catalysis B:Environmental, 2016,187:47-58.
Ding M Y, Wang W, Zhou Y J. Facile in situ synthesis of 2D porous g-C3N4and g-C3N4/P25(N) heterojunction with enhanced quantum effect for efficient photocatalytic application[J]. Journal of Alloys and Compounds, 2015,635:34-40.
Papailias I, Todorova N, Giannakopoulou T, et al. Photocatalytic activity of modified g-C3N4/TiO2 nanocomposites for NOX removal[J]. Catalysis Today, 2017,280:37-44.
苏海英,王盈霏,王枫亮,等.g-C3N4/TiO2复合材料光催化降解布洛芬的机制[J]. 中国环境科学, 2017,37(1):195-202. SuH Y, Wang Y F, Wang F L, et al. Preparation of g-C3N4/TiO2 compositesand the mechanism research of thephotocatalysisde gradation of ibuprofen[J]. China Environmental Science, 2017,37(1):195-202.
Giannakopoulou T, Papailias I, Todorova N, et al. Tailoring the energy band gap and edges' potentials of g-C3N4/TiO2 composite photocatalysts for NOx removal[J]. Chemical Engineering Journal, 2017,310:571-580.
TripathiAlok, Narayanan S. Impact of TiO2 and TiO2/g-C3N4 nanocomposite to treat industrial wastewater[J]. Environmental Nanotechnology, Monitoring & Management, 2018,10:280-291.
Dong F, Wang Z Y, Sun Y J, et al. Engineering the nanoarchitecture and texture of polymeric carbon nitride semiconductor for enhanced visible light photocatalytic activity[J]. Journal of Colloid Interface Science, 2013,401(8):70-79.
Ma T Y, Tang Y H, Dai S, et al. Proton-functionalized two-dimensional graphitic carbon nitride nanosheet:An excellent metal-/label-free biosensing platform[J]. Small, 2014,10(12):2382-2389.
任学昌,念娟妮,王雪姣,等.TiO2/PPY/Fe3O4的水热法制备及其光催化与磁回收性能[J]. 中国环境科学, 2012,32(5):863-868. Ren X C, Nian J N, Wang X J, et al. Hydrothermal synthesis of TiO2/PPY/Fe3O4 and its photocatalytic activity and magnetic recovery[J]. China Environmental Science, 2012,32(5):863-868.
Xie L F, Ni J, Tang B, et al. A self-assembled 2D/2D-type protonated carbon nitride-modified graphene oxide nanocom-posite with improved photocatalytic activity[J]. Applied SurfaceScience, 2018, 434:456-463.
Zhang S W, Li J X, Wang X K, et al. In stiu ion exchange synthesis of strong coupled Ag@AgCl/g-C3N4 porous nanosheets as plasmonicphotocatalyst for highly efficient visible-light photocatalysis[J]. ACS Applied Materials & Interfaces, 2014,6(24):22116-22125.
Ma L N, Wang G H, Jiang C J, et al. Synthesis of core-shell TiO2@g-C3N4 hollow microspheres for efficient photocatalytic degradation of rhodamine B under visible light[J]. Applied Surface Science, 2018,430:263-272.
Du X R, Zou G J, Wang Z H, et al. A scalable chemical route to soluble acidified graphitic carbon nitride:an ideal precursor for isolated ultrathin g-C3N4 nanosheets[J]. Nanoscale, 2015,7(19):8701-8706.
Hu X F, Mohamood T, Ma W H, et al. Oxidative decomposition of rhodamine B dye in the presence of VO2+ and/or Pt(IV) under visible light irradiation:N-deethylation, chromophore cleavage, and mineralization[J]. Journal of Physical Chemistry B, 2006,110(51):26012-26018.
Zhuang J D, Dai W X, Tian Q F, et al. Photocatalytic degradation of RhB over TiO2 bilayer films:Effect of defects and their location[J]. Langmuir, 2010,26(12):9686-9694.
吴斌,方艳芬,任慧君,等.g-C3N4光催化降解2.4-DCP的活性及机理[J]. 环境化学, 2017,36(7):1484-1491. Wu B, Fang Y F, Ren H J, et al. Acticity and mechanism of photocatalytic degradation for 2.4-DCP overg-C3N4[J]. Environmental Chemistry, 2017,36(7):1484-1491.
丁延伟,张仕定,陈韦,等.纳米TiO2光催化氧化异丙醇和丙酮反应的研究[J]. 环境化学, 2003,22(6):555-559. Ding Y W, Zhang S D, Chen W, et al. A research of the photocatalytic oxidation reaction of i-propanol and acetone with nanoscale TiO2[J]. Environmental Chemistry, 2003,22(6):555-559.
Yin L L, Zhao M, Hu H L, et al. Synthesis of graphene/tourmaline/TiO2 composites with enhanced activity for photocatalytic degradation of 2-propanol[J]. Chinese Journal of Catalysis, 2017, 38(8):1307-1314.
Hong Y Z, Jiang Y H, Li C S, et al. In-situ synthesis of direct solid-state Z-scheme V2O5/g-C3N4 hetero-junctions with enhanced visible light efficiency in photocatalytic degradation of pollutants[J]. Applied Catalysis B:Environmental, 2016,180:663-673.
Bao Y C, Chen K Z. Novel Z-scheme BiOBr/reduced graphene oxide/protonated g-C3N4 photocatalyst:Synthesis, characterization, visible light photocatalytic activity and mechanism[J]. Applied Surface Science, 2018,437:51-61.
Kim J, Lee C W, Choi W. Platinized WO3 as an environmental photocatalyst that generates OH radicals under visible light[J]. Environmental Science & Technology, 2010,44(17):6849-6854.