Enhanced nitrogen photofixation on Fe-doped TiO2 with highly exposed (101) facets in the presence of ethanol as scavenger
Enhanced nitrogen photofixation on Fe-doped TiO2 with highly exposed (101) facets in the presence of ethanol as scavenger
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DOI：
10.1016/j.apcatb.2013.07.047
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发表时间：
2014
影响因子：
22.1
通讯作者：
Weirong Zhao;Jing Zhang;Xi Zhu;Meng Zhang;Jing Tang;M. Tan;Y. Wang
中科院分区：
文献类型：
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作者：
Weirong Zhao;Jing Zhang;Xi Zhu;Meng Zhang;Jing Tang;M. Tan;Y. Wang
为了更有效地增强氮的光固定作用，采用两步水热法制备了具有高暴露面（1 0 1）的fe掺杂tio2纳米颗粒。在乙醇作为清除剂的情况下，氮的固氮量子产率达到18.27 × 10−2m−2，是原始TiO2的3.84倍。光催化剂的电化学性能表明，Fe3+的最佳掺杂提高了载流子的浓度和光电流密度，从而提高了光催化活性。电子自旋共振谱分析表明，氮的光合作用产生了活性自由基，如自由基dotO2 -和自由基dotOH。氮光合作用的量子产率取决于反应中氮的分压。通过系统的实验研究，结合密度泛函理论对中间体的周期性计算，揭示了氮光合作用的内在电子传递途径和机理。将1 mol n2还原为2 mol nh3，在tio2上消耗6 mol电子的整个过程与传统的生物固氮过程相似。所提出的电子转移机制可能对其他使用半导体材料作为光催化剂的应用有用。
To enhance nitrogen photofixation more effectively, Fe-doped TiO2nanoparticles with highly exposed (1 0 1) facets were prepared successfully by two-step hydrothermal method. The quantum yield of nitrogen photofixation in the presence of ethanol as scavenger can be significantly enhanced to 18.27 × 10−2m−2which is 3.84 times higher than pristine TiO2. The electrochemical properties of the photocatalyst reveal that the improvement of photocatalytic activity can be attributed to the enhancement of charge carrier's concentration and photocurrent density by the optimal doping of Fe3+. The electron spin-resonance spectroscopy demonstrates the generation of active radicals such as radical dotO2−and radical dotOH in the nitrogen photofixation. The quantum yields of nitrogen photofixation depend on the partial pressure of nitrogen in the reaction. A systematic experimental investigation companying with periodic density functional theory calculation into the intermediates reveals the intrinsic electron transfer pathways and the mechanism of nitrogen photofixation. The entire reduction process of 1 mol N2to 2 mol NH3with consumption of 6 mol electrons on TiO2is similar to the traditional biological nitrogen fixation process. The proposed electron transfer mechanism may be useful to other applications, which use semiconductor materials as photocatalysts.