高等学校化学学报

• 研究论文 •    

高催化活性M-BHT(M=Co, Cu)电催化还原CO2为CH4的密度泛函理论研究

杨涛1,2,姚会影2,李青1,郝伟3,迟力峰1,朱嘉2   

  1. 1.苏州大学功能纳米与软物质研究院,江苏省碳基功能材料与 器件高技术研究重点实验室,苏州 215123
    2.北京师范大学化学学院,北京 100875
    3.南洋理工大学材料科学与工程学院,新加坡 639798
  • 收稿日期:2020-10-04 出版日期:2021-01-05 发布日期:2021-01-05
  • 基金资助:
    国家自然科学基金(批准号(21790053);51821002, 21773016)资助

Density Functional Theoritical Studies on the Promising Electrocatalyst of M-BHT(M=Co or Cu) for CO2 Reduction to CH4

YANG Tao1,2, YAO Huiying2, LI Qing1, HAO Wei3(), CHI Lifeng1, ZHU Jia2   

  1. 1.Institute of Functional Nano and Soft Materials(FUNSOM),Jiangsu Key Laboratory for Carbon?Based Functional Materials and Devices,Soochow University,Suzhou 215123,China
    2.College of Chemistry,Beijing Normal University,Beijing 100875,China
    3.School of Materials Science and Engineering,Nanyang Technological University,Singapore 639798,Singapore
  • Received:2020-10-04 Online:2021-01-05 Published:2021-01-05
  • Contact: HAO Wei E-mail:haowei@ntu.edu.sg

摘要:

具有独特电子结构和丰富催化位点的二维金属有机框架材料是具有高活性的CO2还原反应的电催化剂. 本文基于密度泛函理论(DFT)计算, 发现单层Co-BHT(BHT=benzenehexathiol, 苯六硫醇)将CO2还原为CH4时具有很高的催化活性. 吉布斯自由能变化计算结果表明, 在Co-BHT上将CO2还原成CH4的最佳反应路径为CO2*COOH→*CO→*CHO→*CHOH→*CH→*CH2*CH3→CH4; 整个反应的速度控制步骤为*CO→*CHO; 速度控制步骤的吉布斯自由能变化(ΔGL)为0.66 eV, 比在二维Cu-C3N4GL=0.75 eV)和传统的Cu(211) 表面(ΔGL=0.74 eV) 将CO2还原为CH4的吉布斯自由能变化都小. 而在单层Cu-BHT表面的反应路径和速度控制步骤 (CO2*COOH)与Co-BHT均不同, 且ΔGL为0.76 eV. 与Cu-BHT相比, Co-BHT将CO2还原为CH4的ΔGL更低, 这可能归因于Co-BHT的d能带中心高于Cu-BHT, 导致Co-BHT与中间体的相互作用更强.

关键词: 二氧化碳还原反应, 二维电催化剂, 密度泛函理论, 电催化机理, 吉布斯自由能

Abstract:

Two-dimensional metal organic frame materials show excellent electrocatalytic activity for CO2 reduction reaction because of their unique electronic structures and abundant catalytic sites. Herein, based on density functional theory calculations, we found that monolayer Co-BHT(BHT=benzenehexathiol) exhibits promising electrocatalytic activity in CO2 reduction to CH4. The Gibbs free energy change calculations reveal that the optimal reaction path of CO2 reduction to CH4 on Co-BHT is CO2*COOH→*CO→*CHO→ *CHOH→*CH→*CH2*CH3→CH4, with the rate-limiting step of *CO→*CHO. The Gibbs free energy change of the rate-limiting step(ΔGL) is 0.66 eV, lower than that on both 2D Cu-C3N4(ΔGL=0.75 eV) and traditional Cu(211)(ΔGL=0.74 eV). Furthermore, the studies for monolayer Cu-BHT were also carried out, where the optimal reaction path is different, and the rate-limiting step is CO2*COOH with the ΔGL of 0.76 eV. The lower ΔGL of CO2 reduction on Co-BHT than that on Cu-BHT may be attributed to its higher d-band center compared with that of Cu-BHT, which leads to stronger interactions with the intermediates. Our work predicts the promising electrocatalytic activity of Co-BHT and provides useful insights into the catalytic mechanism and performance of Metal-BHT for CO2 reduction to CH4.

Key words: Carbon dioxide reduction reaction, Two-dimensional electrocatalyst, Density functional theory, Electrocatalytic mechanism, Gibbs free energy

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