Elucidating the Role of Single-Atom Pd for Electrocatalytic Hydrodechlorination

In this study, we loaded Pd catalysts onto a reduced graphene oxide (rGO) support in an atomically dispersed fashion [i.e., Pd single-atom catalysts (SACs) on rGO or Pd-1/rGO] via a facile and scalable synthesis based on anchor-site and photoreduction techniques. The as-synthesized Pd-1/rGO significantly outperformed the Pd nanoparticle (Pdnano) counterparts in the electrocatalytic hydrodechlorination of chlorinated phenols. Downsizing Pdnano to Pd-1 leads to a substantially higher Pd atomic efficiency (14 times that of Pdnano), remarkably reducing the cost for practical applications. The unique single-atom architecture of Pd-1 additionally affects the desorption energy of the intermediate, suppressing the catalyst poisoning by Cl-, which is a prevalent challenge with Pdnano. Characterization and experimental results demonstrate that the superior performance of Pd-1/rGO originates from (1) enhanced interfacial electron transfer through Pd-O bonds due to the electronic metal-support interaction and (2) increased atomic H (H*) utilization efficiency by inhibiting H-2 evolution on Pd-1. This work presents an important example of how the unique geometric and electronic structure of SACs can tune their catalytic performance toward beneficial use in environmental remediation applications.

Automated summary

In this study, Pd catalysts were loaded onto reduced graphene oxide (rGO) in a single-atom fashion, showing significantly improved electrocatalytic performance for hydrodechlorination reactions compared to Pd nanoparticles. The single-atom Pd-1 catalyst enhances Pd atomic efficiency and suppresses catalyst poisoning, leading to cost reduction and increased efficiency in practical applications. The superior performance of Pd-1/rGO is attributed to enhanced electron transfer and increased hydrogen utilization efficiency, showcasing the potential of single-atom catalysts in environmental remediation applications.