N-doped reduced graphene oxide promoted nano TiO2 as a bifunctional adsorbent/photocatalyst for CO2 photoreduction: Effect of N species
N-doped reduced graphene oxide promoted nano TiO2 as a bifunctional adsorbent/photocatalyst for CO2 photoreduction: Effect of N species
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DOI：
10.1016/j.cej.2017.01.125
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发表时间：
2017-05-15
影响因子：
15.1
通讯作者：
Biswas, Pratim
中科院分区：
文献类型：
--
作者：
Lin, Liang-Yi;Nie, Yao;Biswas, Pratim
采用一步法尿素辅助水热法合成了一系列不同氮浓度和键构型的TiO2/N掺杂还原性氧化石墨烯（TiO2/NrGO）纳米复合材料，并将其应用于Xe灯照射下气相H2O蒸汽光还原CO2。考察了N掺杂剂（掺杂量和成键构型）对TiO2/NrGO催化性能的影响。其中，在尿素/氧化石墨烯质量比为300:1的前驱体溶液中，TiO2/NrGO-300的CO产率最高（356.5 μ mol g(-1)）， CO产率分别比纯TiO2和TiO2/rGO提高4.4倍和2.2倍。更重要的是，TiO2/NrGO在长时间反应中表现出优异的催化稳定性，而在几个小时后，TiO2/NrGO和原始TiO2都出现了催化失活现象。研究了N掺杂剂对TiO2/NrGO结构和活性的促进作用。结果表明，具有适当N量和N键构型的NrGO作为双功能促进剂，在增强CO2在催化剂表面吸附和促进电子空穴分离的同时，最终提高了光催化性能。这项工作的实验结果提供了对N掺杂剂在合成复合材料中的关键作用的更好理解，也激发了对更好地设计其他用于光还原CO2的N掺杂石墨烯基材料的持续兴趣。(C) 2017 Elsevier B.V.版权所有
A series of TiO2/nitrogen (N) doped reduced graphene oxide (TiO2/NrGO) nanocomposites with varying concentration and bonding configurations of nitrogen were synthesized by a one-step urea-assisted hydrothermal method, and applied to photoreduction of CO2 with H2O vapor in the gas-phase under the irradiation of a Xe lamp. The effect of the N dopant (doping quantity and bonding configuration) on the catalytic performance of TiO2/NrGO was examined. In particular, TiO2/NrGO-300, with a 300:1 mass ratio of urea/GO in precursor solution, had the highest CO production yield (356.5 mu mol g(-1)), manifesting a significant 4.4 and 2.2-fold enhancements of CO yield over pure TiO2 and TiO2/rGO, respectively. More significantly, TiO2/NrGO showed excellent catalytic stability during the prolonged reaction, while catalytic deactivation was observed for both pristine TiO2 and TiO2/rGO after a few hours. The promoting effects of N dopants on the structure and activity of TiO2/NrGO were investigated. It was demonstrated that NrGO with an appropriate N quantity and N -bonding configuration acted as a dual-functional promoter, simultaneously enhancing CO2 adsorption on the catalyst surface and facilitating electron-hole separation, while eventually boosted the photocatalytic performance. Experimental results in this work provide a better understanding of the critical roles of N dopants in the synthesized composites and also inspire the ongoing interest in better design of other N-doped graphene based materials for photoreduction of CO2. (C) 2017 Elsevier B.V. All rights reserved.