Transformation of surface crystalline phase structure of nano-TiO2 and accompanying photocatalytic activity
WEI Yi-mei1, BAI Yang-wei1, LIU Dan-ni1, GUO Dong-heng2, XU Lin-hui1, JIA Shi-qi1, SUN Fei1
1. Research Center for Comprehensive Control Water Pollution in River Basin, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; 2. Shanxi Research Institute of Environmental Science, Taiyuan 030027, China
Abstract: The surface structure of the catalyst plays an important role in adjusting and controlling its catalytic activity.Herein,the sintering treatment method is used to induce anatase nano-TiO2 to transform into rutile phase.The phase transformation is verified by XRD patterns.It is found from analyzing the photocatalytic activity and the content of rutile phase that even a small amount of rutile phase is formed,the photocatalytic activity of nano-TiO2 can be improved greatly and the relative content of different free radicals in the catalytic system will be obviously changed.The generation concentration of ·OH enhances slightly but the generation concentration of O2-increases significantly from 0.233 μM·h-1 to 0.501 μM·h-1,which suggests an obvious structure change occurs on nano-TiO2 surface during sintering process,probably anatase-to-rutile phase transformation occurs preferentially in the surface area of nano-TiO2 particles.Compared with the model rutile/anatase nano-TiO2 surface heterostructure,it is further verified that the surface crystalline heterostructure can significantly improve the catalytic activity of nano-TiO2.To further demonstrate the formation of surface phase heterostructure,a model anatase/rutile TiO2 composite with surface heterostructure is fabricated for comparison,which verifies that the enhanced photocatalytic activity arises from the formation of surface anatase/rutile phase heterostructure.
[1] Zhang H,Chen G,Bahnemann D W.Photoelectrocatalytic materials for environmental applications[J].Journal of Materials Chemistry,2009,19(29):5089-5121. [2] 王丽,赵辉,刘进,等.非均相多酸催化剂在光催化领域的应用研究进展[J].工业水处理,2019,39(8):9-18. [3] Ollis D F,Pelizzetti E,Serpone N.Photocatalyzed destruction of water contaminants[J].Environmental Science & Technology,1991,25(9):1522-1529. [4] Roy P,Berger S,Schmuki P.TiO2 Nanotubes:Synthesis and applications[J].Angewandte Chemie International Edition,2011,50(13):2904-2940. [5] Schneider J,Matsuoka M,Takeuchi M,et al.Understanding TiO2 photocatalysis:Mechanisms and materials[J].Chemical Reviews,2014,114(19):9919-9986. [6] Bourikas K,Kordulis C,Lycourghiotis A.Titanium dioxide (anatase and rutile):Surface chemistry,liquid-solid interface chemistry,and scientific synthesis of supported catalysts[J].Chemical Reviews,2014,114(19):9754-9823. [7] Scanlon D O,Dunnill C W,Buckeridge J,et al.Band alignment of rutile and anatase TiO2[J].Nature Materials,2013,12(7):798-801. [8] Hurum D C,Agrios A G,Gray K A,et al.Explaining the enhanced photocatalytic activity of degussa P25 mixed-phase TiO2 using EPR[J].The Journal of Physical Chemistry B,2003,107(19):4545-4549. [9] Li G,Dimitrijevic N M,Chen L,et al.The important role of tetrahedral Ti4+ sites in the phase transformation and photocatalytic activity of TiO2 nanocomposites[J].Journal of the American Chemical Society,2008,130(16):5402-5403. [10] Zhou Y,Fichthorn K A.Microscopic view of nucleation in the anatase-to-rutile transformation[J].The Journal of Physical Chemistry C,2012,116(14):8314-8321. [11] Carneiro J T,Savenije T J,Moulijn J A,et al.How phase composition influences optoelectronic and photocatalytic properties of TiO2[J].The Journal of Physical Chemistry C,2011,115(5):2211-2217. [12] 黄兵华,张晓飞,宋磊,等.TiO2光催化水处理技术综述[J].水处理技术,2014,40(3):11-21. [13] Imanishi A,Fukui K.Atomic-scale surface local structure of TiO2 and its influence on the water photooxidation process[J].The Journal of Physical Chemistry Letters,2014,5(12):2108-2117. [14] Zhao L,Chen X,Wang X,et al.One-step solvothermal synthesis of a carbon@TiO2 dyade structure effectively promoting visible-light photocatalysis[J].Advanced Materials,2010,22(30):3317-3321. [15] Li Y,Zhang W,Niu J,et al.Mechanism of photogenerated reactive oxygen species and correlation with the antibacterial properties of engineered metal-oxide nanoparticles[J].ACS Nano,2012,6(6):5164-5173. [16] Su R,Bechstein R,Sø L,et al.How the anatase-to-rutile ratio influences the photoreactivity of TiO2[J].The Journal of Physical Chemistry C,2011,115(49):24287-24292. [17] Ma R,Chen T.Checking the synergetic effect between anatase and rutile[J].The Journal of Physical Chemistry C,2019,123(32):19479-19485. [18] Zhang J,Nosaka Y.Mechanism of the OH radical generation in photocatalysis with TiO2 of different crystalline types[J].The Journal of Physical Chemistry C,2014,118(20):10824-10832. [19] 李明洁,喻泽斌,陈颖,等.TiO2光催化降解PFOA的反应动力学及机制研究[J].环境科学,2014,35(7):2612-2619. [20] Zhang J,Xu Q,Feng Z,et al.Importance of the relationship between surface phases and photocatalytic activity of TiO2[J].Angewandte Chemie International Edition,2008,47(9):1766-1769.