Department of Chemistry and Stephenson Institute for Renewable Energy, University of Liverpool , L69 7ZD Liverpool, United Kingdom.
Central Laser Facility, STFC Rutherford Appleton Laboratory , Harwell, Didcot, Oxfordshire OX11 0QX, United Kingdom.
J Am Chem Soc. 2017 Oct 4;139(39):13791-13797. doi: 10.1021/jacs.7b06898. Epub 2017 Sep 20.
Group 6 metal carbonyl complexes ([M(bpy)(CO)], M = Cr, Mo, W) are potentially promising CO reduction electrocatalysts. However, catalytic activity onsets at prohibitively negative potentials and is highly dependent on the nature of the working electrode. Here we report in situ vibrational SFG (VSFG) measurements of the electrocatalyst [Mo(bpy)(CO)] at platinum and gold electrodes. The greatly improved onset potential for electrocatalytic CO reduction at gold electrodes is due to the formation of the catalytically active species [Mo(bpy)(CO)] via a second pathway at more positive potentials, likely avoiding the need for the generation of [Mo(bpy)(CO)]. VSFG studies demonstrate that the strength of the interaction between initially generated [Mo(bpy)(CO)] and the electrode is critical in enabling the formation of the active catalyst via the low energy pathway. By careful control of electrode material, solvent and electrolyte salt, it should therefore be possible to attain levels of activity with group 6 complexes equivalent to their much more widely studied group 7 analogues.
第六族金属羰基配合物([M(bpy)(CO)]，M = Cr，Mo，W)是很有前途的 CO 还原电催化剂。然而，其催化活性的起始电位非常负，并且高度依赖于工作电极的性质。在这里，我们报道了在铂和金电极上原位振动表面增强拉曼散射（VSFG）测量[Mo(bpy)(CO)]的结果。在金电极上，电催化 CO 还原的起始电位得到了极大的改善，这是由于在更正的电位下通过第二条途径形成了催化活性物种[Mo(bpy)(CO)]，可能避免了生成[Mo(bpy)(CO)]的需要。VSFG 研究表明，最初生成的[Mo(bpy)(CO)]与电极之间相互作用的强度对于通过低能量途径形成活性催化剂至关重要。因此，通过仔细控制电极材料、溶剂和电解质盐，应该有可能达到与研究更为广泛的第七族类似物相当的第六族配合物的活性水平。
