Breaking Scaling Relationships in CO₂ Reduction on Copper Alloys with Organic Additives

Abstract

Boundary conditions for catalyst performance in the conversion of common precursors such as N₂, O₂, H₂O, and CO₂ are governed by linear free energy and scaling relationships. Knowledge of these limits offers an impetus for designing strategies to alter reaction mechanisms to improve performance. Typically, experimental demonstrations of linear trends and deviations from them are composed of a small number of data points constrained by inherent experimental limitations. Herein, high-throughput experimentation on 14 bulk copper bimetallic alloys allowed for data-driven identification of a scaling relationship between the partial current densities of methane and C₂₊ products. This strict dependence represents an intrinsic limit to the Faradaic efficiency for C–C coupling. We have furthermore demonstrated that coating the electrodes with a molecular film breaks the scaling relationship to promote C₂₊ product formation.