Breaking the Limit of Size-Dependent CO<sub>2</sub>RR Selectivity in Silver Nanoparticle Electrocatalysts through Electronic Metal–Carbon Interactions
Xingyi Deng, Dominic Alfonso, Thuy‐Duong Nguyen‐Phan, Douglas R. Kauffman
Abstract
High Resolution Image Download MS PowerPoint Slide We demonstrate that electronic metal–support interactions (EMSIs) between silver and carbon can dramatically improve the CO 2 reduction reaction (CO 2 RR) performance of the small Ag nanoparticles. Ag–C EMSIs were created by ultrahigh vacuum deposition of Ag onto defect-containing (sputtered) highly oriented pyrolytic graphite, and calculations predicted that 1.02 e was transferred from Ag to carbon, which stabilized the *COOH reaction intermediate, lowered the potential-limiting CO 2 RR step, and improved the predicted CO 2 -to-CO performance. Experimentally, we identified a scaling relationship between particle size and the relative Ag–C EMSI strength, which improved the CO 2 -to-CO Faradaic efficiency of sub-2 nm Ag particles from 2 to ∼100% and increased the CO turnover frequency ∼15-fold compared with similarly sized Ag particles grown in the absence of Ag–C EMSIs. We extended this concept to grow sub-2 nm Ag electrocatalysts on commonly used carbon black catalyst supports and showed that the interaction with support defects could sustain CO selectivity comparable to larger particles, suggesting an approach for tailoring CO 2 RR electrocatalyst performance.