arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1707.03031physics.chem-ph
收藏

金红石TiO $_2$（110）光催化固氮的分析

Analysis of Photocatalytic Nitrogen Fixation on Rutile TiO$_2$(110)

Benjamin M. Comer, Andrew J. Medford

阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

光催化固氮为在温和条件下生产活性氮化合物提供了一条很有前途的途径。据报道，二氧化钛是一种将二氮还原为氨的活性光催化剂;然而，对这一过程如何发生的基本理解很少。在这项工作中，金红石（110）模型表面被假设为活性位点，和计算模型的基础上的贝叶斯误差估计功能（BEEF-vdW）和计算氢电极应用，以分析预期的二氮覆盖在表面以及电化学还原和氧化的过电位。这是计算技术在光催化固氮中的首次应用，结果表明，金红石（110）上氮还原的热力学极限电位远高于金红石TiO $_2$的导带边，即使在氧空位和铁取代的情况下。这项工作提供了强有力的证据，反对最常见的实验假设，并表明金红石（110）是不可能的相关表面的氮还原。然而，金红石（110）上氮氧化的极限电位显著较低，表明氧化途径可能与金红石（110）有关。这些研究结果表明，光催化固氮可能发生通过氧化和还原过程的复杂平衡。

英文摘要：

Photocatalytic nitrogen fixation provides a promising route to produce reactive nitrogen compounds at benign conditions. Titania has been reported as an active photocatalyst for reduction of dinitrogen to ammonia; however there is little fundamental understanding of how this process occurs. In this work the rutile (110) model surface is hypothesized to be the active site, and a computational model based on the Bayesian error estimation functional (BEEF-vdW) and computational hydrogen electrode is applied in order to analyze the expected dinitrogen coverage at the surface as well as the overpotentials for electrochemical reduction and oxidation. This is the first application of computational techniques to photocatalytic nitrogen fixation, and the results indicate that the thermodynamic limiting potential for nitrogen reduction on rutile (110) is considerably higher than the conduction band edge of rutile TiO$_2$, even at oxygen vacancies and iron substitutions. This work provides strong evidence against the most commonly reported experimental hypotheses, and indicates that rutile (110) is unlikely to be the relevant surface for nitrogen reduction. However, the limiting potential for nitrogen oxidation on rutile (110) is significantly lower, indicating that oxidative pathways may be relevant on rutile (110). These findings suggest that photocatalytic dinitrogen fixation may occur via a complex balance of oxidative and reductive processes.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑