Breaking the\nLinear Scaling Relationship by Alloying\nMicro Sn to a Cu Surface toward CO<sub>2</sub> Electrochemical Reduction

The electrochemical CO<sub>2</sub> reduction reaction\n(CO<sub>2</sub>RR) to HCOOH provides an avenue for reducing global\naccelerated CO<sub>2</sub> emissions and producing high-value-added\nchemicals. Nevertheless,\nthe presence of an inherent linear scaling relationship (LSR) between\n*OCHO and *HCOOH leads to the electrosynthesis of HCOOH being achieved\nat high cathodic potentials. In this work, by adjusting the different\nCu:Sn ratio of Sn<sub><i>x</i></sub>Cu<sub>(1–<i>x</i>)</sub> alloys, we comprehensively explored the electrocatalytic\n2e<sup>–</sup> CO<sub>2</sub>RR performance toward the production\nof HCOOH. Combining density functional theory calculations with the\nconstant-potential implicit solvent model, the Sn<sub>0.03</sub>Cu<sub>0.97</sub> surface alloy was posited to be a promising electrocatalyst\nwith superior HCOOH selectivity and an ultralow limiting potential\nof −0.20 V in an environment of pH = 7.2. The high performance\nwas found to originate from the breaking of the LSR, which is a result\nof an extraordinary electronic property of the active Cu site. This\nwork not only advances a global-searched strategy for the rational\ndesign of efficient catalysts toward HCOOH production but also provides\nin-depth insights into the underlying mechanism for the enhanced performance\nof microalloy electrocatalysts.