Experimental and Theoretical Factors in CO₂ Reduction on Pd‐Based Electrocatalysts and their Applicability for Integration with Data Science and High‐Throughput Experiments

This review showcases crucial factors in mechanisms of electrochemical CO 2 reduction by taking Pd‐based electrocatalysts (mainly, monometallic Pd and Pd‐based alloy nanoparticles) as examples. There are dependencies of experimental conditions (e.g., applied potentials) and constituent elements of the electrocatalysts on the reduction products of electrochemical CO 2 reduction. Moreover, Pd‐based electrocatalysts have unique characteristics in electrochemical CO 2 reduction: alteration in selectivities for CO and HCOOH formations by applied potentials, almost no overpotential for HCOOH formation, deactivation of their electrocatalyses by poisoning with CO formed through CO 2 reduction, and in situ formation of palladium hydride. Here, we survey the characteristics of Pd‐based electrocatalysts in terms of experimental and theoretical insights. Then, it is described that formation energies of intermediates estimated by density functional theory calculations are understandable factors to explain experimental performances of Pd‐based electrocatalysts. Considering the estimated factors, this review exhibits a perspective of utilization of the factors to advance the research activity of electrochemical CO 2 reduction to its new horizon by using data science and high‐throughput experiments.