单层石墨相氮化碳负载Pt_4团簇吸附O_2的第一性理论研究（英文）  

Pt_4Clusters Supported on Monolayer Graphitic Carbon Nitride Sheets for Oxygen Adsorption: A First-Principles Study

作　　者：左会文 陆春海[2] 任玉荣[3] 李奕[1] 章永凡[1] 陈文凯[1,4,5] 

机构地区：[1]福州大学化学系,福州350116 [2]成都理工大学核技术与自动化工程学院,成都610059 [3]常州大学材料与工程学院,江苏常州213164 [4]福建省理论与计算化学重点实验室,福建厦门361005 [5]福州大学、能源与环境光催化国家重点实验室,福州350002

出　　处：《物理化学学报》2016年第5期1183-1190,共8页Acta Physico-Chimica Sinica

基　　金：supported by the National Natural Science Foundation of China(21203227,51574090)~~

摘　　要：采用第一性原理密度泛函理论结合周期性平板模型模拟研究了Pt_4团簇吸附单层石墨相氮化碳(g-C_3N_4)的几何结构和电子性质,以及氧气在其表面上的吸附行为。同时,对比分析了氧气在纯净的石墨相氮化碳和Pt_4团簇上的吸附行为。计算结果表明,Pt_4团簇吸附在3-s-三嗪环石墨相氮化碳表面,并与四个边缘氮原子成键,形成两个六元环时为最稳定构型。Pt_4团簇倾向于吸附在三嗪环石墨相氮化碳的空位并与邻近三个氮原子成键。由于Pt与N原子较强的杂化作用,以及金属与底物之间较多电子转移增强了Pt_4团簇吸附g-C_3N_4的稳定性。另外,对比分析了氧气在纯净的g-C_3N_4和金属吸附的g-C_3N_4上吸附行为,发现金属原子的加入促进了电子转移,同时拉长了O―O键长。Pt_4吸附3-s-三嗪环g-C_3N_4比Pt_4吸附三嗪环g-C_3N_4表现出微弱的优势,表现出明显的基底扭曲以及较大的吸附能。这些结果表明,化学吸附通过调节电子结构和表面性质增强催化性能的较好方法。The structural and electronic properties of Pt4 nanoparticles adsorbed on monolayer graphitic carbon nitride（Pt4/g-C3N4）, as well as the adsorption behavior of oxygen molecules on the Pt4/g-C3N4 surface have been investigated through first-principles density-functional theory（DFT） calculations with the generalized gradient approximation（GGA）. The interaction of the oxygen molecules with the bare g-C3N4 and the Pt4 clusters was also calculated for comparison. Our calculations show that Pt nanoparticles prefer to bond with four edge N atoms on heptazine phase g-C3N4（HGCN） surfaces, forming two hexagonal rings. For s-triazine phase g-C3N4（TGCN） surfaces, Pt nanoparticles prefer to sit atop the single vacancy site, forming three bonds with the nearest nitrogen atoms. Stronger hybridization of the Pt nanoparticles with the sp-2 dangling bonds of neighboring nitrogenatoms leads to the Pt4 clusters strongly binding on both types of g-C3N4 surface. In addition, the results from Mulliken charge population analyses suggest that there are electrons flowing from the Pt clusters to g-C3N4.According to the comparative analyses of the O2 adsorbed on the Pt4/HGCN, Pt4/TGCN, and pure g- C3N4 systems, the presence of metal clusters promotes greater electron transfer to oxygen molecules and elongates the O―O bond. Meanwhile, its greater adsorbate-substrate distortion and large adsorption energy render the Pt4/HGCN system slightly superior to the Pt4/TGCN system in catalytic performance. The results validate that being supported on g-C3N4 may be a good way to modify the electronic structure of materials and their surface properties improve their catalytic performance.

关 键 词：石墨相氮化碳 铂簇 氧气分子 吸附 光催化剂 密度泛函理论 

分 类 号：O647.3[理学—物理化学]