Mechanistic reaction pathways of enhanced ethylene yields during electroreduction of CO2-CO co-feeds on Cu and Cu-tandem electrocatalysts.,Nature Nanotechnology

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Mechanistic reaction pathways of enhanced ethylene yields during electroreduction of CO2-CO co-feeds on Cu and Cu-tandem electrocatalysts.
Nature Nanotechnology ( IF 38.1 ) Pub Date : 2019-10-07 , DOI: 10.1038/s41565-019-0551-6
Xingli Wang ₁ , Jorge Ferreira de Araújo ₁ , Wen Ju ₁ , Alexander Bagger ₂ , Henrike Schmies ₁ , Stefanie Kühl ₁ , Jan Rossmeisl ₂ , Peter Strasser ₁

Affiliation

Unlike energy efficiency and selectivity challenges, the kinetic effects of impure or intentionally mixed CO2 feeds on the catalytic reactivity of the direct electrochemical CO2 reduction reaction (CO2RR) have been poorly studied. Given that industrial CO2 feeds are often contaminated with CO, a closer investigation of the CO2RR under CO2/CO co-feed conditions is warranted. Here, we report mechanistic insights into the CO2RR reactivity of CO2/CO co-feeds on Cu-based nanocatalysts. Kinetic isotope-labelling experiments-performed in an operando differential electrochemical mass spectrometry capillary flow cell with millisecond time resolution-showed an unexpected enhanced production of C2H4, with a yield increase of almost 50%, from a cross-coupled 12CO2-13CO reactive pathway. The results suggest the absence of site competition between CO2 and CO molecules on the reactive surface at the reactant-specific sites. The practical significance of sustained local interfacial CO partial pressures under CO2 depletion is demonstrated by metallic/non-metallic Cu/Ni-N-doped carbon tandem catalysts. Our findings show the mechanistic origin of improved C2 product formation under co-feeding, but also highlight technological opportunities of impure CO2/CO process feeds for H2O/CO2 co-electrolysers.

中文翻译：

在Cu和Cu串联电催化剂上电还原CO2-CO共进料过程中提高乙烯收率的机理反应途径。

与能源效率和选择性挑战不同，不纯或有意混合的CO2进料对直接电化学CO2还原反应（CO2RR）的催化反应性的动力学影响尚未得到很好的研究。鉴于工业CO2进料经常被CO污染，因此有必要在CO2 / CO共进料条件下对CO2RR进行更深入的研究。在这里，我们报告机理的见解，对基于铜的纳米催化剂上的CO2 / CO共进料的CO2RR反应性。在具有毫秒级时间分辨力的操作差分电化学质谱毛细管流动池中进行的动力学同位素标记实验显示，C12H4的产量出乎意料地提高，通过交叉偶联的12CO2-13CO反应路径增加了近50％的产率。结果表明在反应物特异性位点的反应表面上，CO 2和CO分子之间不存在位点竞争。金属/非金属掺杂Cu / Ni-N的碳串联催化剂证明了在CO2消耗下持续局部界面CO分压的实际意义。我们的发现表明，在共同进料下改善C2产物形成的机理起源，但同时也突出了不纯的CO2 / CO工艺进料用于H2O / CO2电解槽的技术机会。

更新日期：2019-10-07

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