A Singapore Berkeley Research Initiative for Sustainable Energy , Berkeley Educational Alliance for Research in Singapore , 1 CREATE Way , 138602 Singapore.
NUSNNI-Nanocore , National University of Singapore , 117411 Singapore.
ACS Appl Mater Interfaces. 2018 Mar 14;10(10):8574-8584. doi: 10.1021/acsami.7b15418. Epub 2018 Feb 26.
Copper oxides have been of considerable interest as electrocatalysts for CO reduction (CO2R) in aqueous electrolytes. However, their role as an active catalyst in reducing the required overpotential and improving the selectivity of reaction compared with that of polycrystalline copper remains controversial. Here, we introduce the use of selected-ion flow tube mass spectrometry, in concert with chronopotentiometry, in situ Raman spectroscopy, and computational modeling, to investigate CO2R on CuO nanoneedles, CuO nanocrystals, and CuO nanoparticles. We show experimentally that the selective formation of gaseous C products (i.e., ethylene) in CO2R is preceded by the reduction of the copper oxide (CuOR) surface to metallic copper. On the basis of density functional theory modeling, CO2R products are not formed as long as CuO is present at the surface because CuOR is kinetically and energetically more favorable than CO2R.
氧化铜作为电催化剂在水溶液中还原 CO（CO2R）引起了相当大的关注。然而，与多晶铜相比，其在降低所需过电势和提高反应选择性方面的作用仍存在争议。在这里，我们采用选定离子流管质谱、恒电流计时电位法、原位拉曼光谱和计算建模相结合的方法，研究了 CuO 纳米针、CuO 纳米晶和 CuO 纳米颗粒上的 CO2R。我们的实验表明，在 CO2R 中，气态 C 产物（即乙烯）的选择性形成是由氧化铜（CuOR）表面还原为金属铜引起的。基于密度泛函理论模型，只要表面存在 CuO，就不会形成 CO2R 产物，因为 CuOR 在动力学和能量上比 CO2R 更有利。
