Modification of Palladium Nanocrystals with Single Atom Platinum via an Electrochemical Self-Catalysis Strategy for Efficient Formic Acid Electrooxidation

Abstract

Single atom alloys (SAA) have recently drawn increased attention due to their unique structure, high atomic utilization, and fascinating catalytic performance. However, their controllable synthesis still presents a challenge. This study proposes an electrochemical self-catalysis (ESC) strategy to synthesize Pd@Pt/ C SAA catalysts, that is, depositing Pt atoms on Pd nanocrystals through in situ decomposition of sodium formate. The relationship between composition and structure of Pd@Pt/C is distinguished through a combination of electrochemical analysis, sphere-corrected scanning transmission electron microscopy, and X-ray adsorption spectra. That relationship evolved from SAA to a sea-island structure and even a core−shell structure with composition-controllable atomic ratios, highlighting the great diversity and convenience of this method in nanostructure construction. The Pd@Pt/C SAA catalyst showed excellent catalytic activity to formic acid oxidation with a peak current density of 5.2 A/mg metal , which is about 18.6 times that of the commercial Pd/C. density functional theory calculations revealed that the enhanced activity was due to the "passivation" of Pd sites near the Pt single atoms, which attenuated the adsorption of CO. Based on electrochemical principles, this ESC strategy was also expanded to prepare a series of Pd-based SAA, including Pd−Au, Pd−Ir, and Pd−Bi.

Boosting the Electrocatalytic Formic Acid Oxidation Activity via P-PdAuAg Quaternary Alloying

“…The adsorption peak to oxygen-containing species of P-PdAuAg is ∼0.15 V lower than that of commercial Pd/C. This indicates enhanced adsorption to oxygen-containing reaction intermediates, which is beneficial for FAOR. − …”

The trimetallic AuAgPt nanowires for light-enhanced formic acid electrolysis

“…have been synthesized and applied as highly active FAOR electrocatalysts. [32][33][34][35][36][37] Among them, gold (Au) is widely selected as the other metal because of its inherent chemical stability and unique localized surface plasmon resonance (LSPR) response. [38][39][40] In particular, the LSPR of Au can generally boost the reactivity of catalysts due to the photoelectron reservoir, hot electron injection, photothermal effect, etc.…”

Defect-driven nanostructuring of low-nuclearity Pt-Mo ensembles for continuous gas-phase formic acid dehydrogenation

“…Formic acid decomposition can proceed via photocatalysis 12,13 , electrocatalysis 14,15 , or thermocatalysis [16][17][18][19][20][21] . As one of the major technologies, thermocatalysis is viable both in liquid and gas phases.…”