C/N自掺杂提高g-C_3N_4光响应的理论研究
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摘要
依托半导体的光催化性能对环境中的污染物进行降解是解决环境污染的一种有效途径.类石墨烯相C_3N_4(g-C_3N_4)具有稳定的化学性能和独特的电子结构,在光催化领域展现出巨大的应用潜力.采用第一性原理,本文对不同比例的C/N自掺杂g-C_3N_4的晶体结构和电子结构进行了探究.通过不同掺杂位形成能的比较,探究了单原子替位掺杂和多原子表面转移掺杂的最优化结构.通过电子结构的比较发现:C原子自掺杂较N原子自掺杂形成能更低,易于在实验中实现;随N掺杂比例的增加, g-C_3N_4的吸收光谱向红外移动; C掺杂比例为1/12时对可见光的响应最强.该理论结果除获得掺杂的微观机理解释,亦利于对后续实验的合成提供理论依据和指导.
It becomes an effective way to solve environmental pollution by using photocatalysis of semiconductors. For the reasons of chemical stabilization and unique electronic structure, polymeric graphitic carbon nitride(g-C_3N_4) has been used extensively in the field of photocatalysis. Using the first principle calculations, optimized crystal structures and electronic structures are calculated for the doped cases. From comparisons of formation energies, the most stable crystal structures are obtained for monatomic substitutional doping cases and polyatomic surface transfer doping ones. The results reveal that C/g-C_3N_4 can be easier synthetized than N/g-C_3N_4 because of its lower formation energy. The results show that the best doping ratio of C is 1/12 for the reason of high visible light response. The calculated results are helpful to provide theoretical basis and instruction for subsequent synthesis in addition to the microscopic mechanism of doping.
It becomes an effective way to solve environmental pollution by using photocatalysis of semiconductors. For the reasons of chemical stabilization and unique electronic structure, polymeric graphitic carbon nitride(g-C_3N_4) has been used extensively in the field of photocatalysis. Using the first principle calculations, optimized crystal structures and electronic structures are calculated for the doped cases. From comparisons of formation energies, the most stable crystal structures are obtained for monatomic substitutional doping cases and polyatomic surface transfer doping ones. The results reveal that C/g-C_3N_4 can be easier synthetized than N/g-C_3N_4 because of its lower formation energy. The results show that the best doping ratio of C is 1/12 for the reason of high visible light response. The calculated results are helpful to provide theoretical basis and instruction for subsequent synthesis in addition to the microscopic mechanism of doping.
引文
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[4]蔡亚平,李卫,冯良桓,等.化学水浴法制备发面积CdS薄膜及其光伏应用[J].物理学报,2009,58:438.
[5]Wang X C,Maeda K,Thomas A,et al.A metalfree polymeric photocatalyst for hydrogen production from water under visible light[J].Nat Mater,2009,8:76.
[6]Yan S C,Li Z S,Zou Z G.Photodegradation of rhodamine b and methyl orange over boron-doped gC3N4under visible light irradiation[J].Langmuir,2010,26:3894.
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[8]Chen G,Gao S P.Dissociations of O2molecules on ultrathin Pb(111)films:first-principles plane wave calculations[J].Chin Phys B,2012,21:380.
[9]Fu J,Zhu B,Jiang C,et al.Hierarchical porous O-doped g-C3N4 with enhanced photocatalytic CO2reduction activity[J].Small,2017,13:1603938.
[10]Zuo F,Wang L,Wu T,et al.Self-doped Ti 3+enhanced photocatalyst for hydrogen production under visible light[J].J Am Chem Soc,2010,132:11856.
[11]顾芳,孙亚飞,张加宏,等.掺杂Si/SiO2界面电子结构与光学性质的第一性原理研究[J].原子与分子物理学报,2018,35:853.
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[13]Li Y,Wu S,Huang L,et al.Synthesis of carbondoped g-C3N4composites with enhanced visible-light photocatalytic activity[J].Mater Lett,2014,137:281.
[14]Oh J S,Kim K N,Yeom G Y J.Graphene doping methods and device applications[J].Nanosci Nanotechnol,2014,14:1120.
[15]Dong G,Zhao K,Zhang L.Carbon self-doping induced high electronic conductivity and photoreactivity of g-C3N4[J].Chem Commun,2012,48:6178.
[16]Zhao Z,Sun Y,Dong F,et al.Template synthesis of carbon self-doped g-C3N4with enhanced visible to near-infrared absorption and photocatalytic performance[J].RSC Adv,2015,5:39549.
[17]Panneri S,Ganguly P,Mohan M,et al.Photoregenerable,bifunctional granules of carbon-doped gC3N4as adsorptive photocatalyst for the efficient removal of tetracycline antibiotic[J].ACS Sustain Chem Eng,2017,5:1610.
[18]Liu G,Li X,Ganesan P,et al.Development of non-precious metal oxygen-reduction catalysts for PEM fuel cells based on N-doped ordered porous carbon[J].Appl Cataly B:Enviro,2009,93:156.
[19]Chen X,Burda C.The electronic origin of the visible-light absorption properties of C-,N-and S-doped TiO2 Nanomaterials[J].J Am Chem Soc,2008,130:5018.
[20]张春红,张忠政,闫万珺,等.稀土Er掺杂β-FeSi2光电捍性研究[J].四川大学学报:自然科学版,2016,53:1335.
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[25]Kresse G,Furthermuller J.Efficient iterative schemes for ab initio total-energy calculations using aplane-wave basis set[J].Phys Rev B,1996,54:11169.