Cu metal embedded in oxidized matrix catalyst to promote CO<sub>2</sub> activation and CO dimerization for electrochemical reduction of CO<sub>2</sub>.

Xiao, Hai; Goddard, William A; Cheng, Tao; Liu, Yuanyue · Proc Natl Acad Sci U S A · 2017

basic_science · Level V

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Abstract

We propose and validate with quantum mechanics methods a unique catalyst for electrochemical reduction of CO<sub>2</sub> (CO<sub>2</sub>RR) in which selectivity and activity of CO and C<sub>2</sub> products are both enhanced at the borders of oxidized and metallic surface regions. This Cu metal embedded in oxidized matrix (MEOM) catalyst is consistent with observations that Cu<sub>2</sub>O-based electrodes improve performance. However, we show that a fully oxidized matrix (FOM) model would not explain the experimentally observed performance boost, and we show that the FOM is not stable under CO<sub>2</sub> reduction conditions. This electrostatic tension between the Cu<sup>+</sup> and Cu<sup>0</sup> surface sites responsible for the MEOM mechanism suggests a unique strategy for designing more efficient and selective electrocatalysts for CO<sub>2</sub>RR to valuable chemicals (HCO<sub>x</sub>), a critical need for practical environmental and energy applications.