Au/TiC (001) 上のチオフェンの脱硫:Au-C相互作用と電荷の偏化
José A Rodriguez1, Ping Liu, Yoshiro Takahashi
1Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973, USA. rodrigez@bnl.gov
Journal of the American Chemical Society
|June 18, 2009
まとめ
炭化チタン (TiC) 表面の金ナノ粒子は,水解硫化を大幅に促進します. このAu/TiCシステムは,チオフェン結合と水素解離を強化し,硫黄除去のための伝統的な触媒を上回る.
科学分野:
- マテリアルサイエンス 材料科学
- 表面化学について
- カタリシス カタリシス カタリシス
背景:
- TiC(001) 上のチオフェンの吸附は弱く,200 K以下での脱吸収があります.
- チオフェンは硫黄経由でTi中心に結合し,TiCの構造の変化は最小限である.
- TiC(001) とAu(111) は,個別に水解硫化性能が悪いことを示している.
研究 の 目的:
- TiC(001) とAu/TiC(001) の表面とのチオフェンの相互作用を調査する.
- Au/TiC ((001) システムの水酸化除硫活性を評価する.
- 触媒活動における金と炭素の相互作用の役割を理解する.
主な方法:
- フォトエミッションスペクトロスコピー.
- 第一原則 密度関数 (DF) 計算.
主要な成果:
- Au/TiC ((001) は,従来のNi/MoS ((x)) 触媒よりも高い水解硫化活性を示しています.
- Au-TiCの相互作用は,Auの周囲の電子密度を極化させ,その反応性を高めます.
- 金ナノ粒子はチオフェンの結合エネルギーを増加させ,H(2) 解離を促進します.
- H (((2) は,TiC (((001) と接触した金塊に自発的に解離する.
- Au/TiC(001) のチオフェン吸附エネルギーは,TiC(001) またはAu(111) よりも0.45-0.65 eV大きい.
- ティオフェンはエタ (((5) の構成を採用し,C-S結合を約0.2 Å延長する.
結論:
- Au/TiC ((001) システムでは,水解硫黄化の可能性が顕著であることが示されています.
- 金ナノ粒子は,結合と水素活性化を改善することにより,触媒活動を強化するために不可欠です.
- 金とTiCの間の相乗効果は,効率的な硫黄除去の鍵です.
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