The Relationships among Hydrogen Adsorption, CO Stripping, and Selectivity of CO 2 Reduction on Pd Nanoparticles

• Published in: Journal of the Electrochemical Society Vol. 168; no. 5; p. 54507
• Main Authors: Guo, Ren-Hao, Hu, Chi-Chang
• Format: Journal Article
• Language: English
• Published: 01.05.2021
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1945-7111/abf17e

The low formation overpotential and strong adsorption ability of CO on palladium surface sites constrain the lower potential limit and current density of the electrochemical reduction of CO 2 (CO 2 ER) to formate on Pd although this reaction has been considered one of the most effective methods for CO 2 recycling. Among various factors, the participation of adsorbed hydrogen atoms seems to be a key factor affecting the selectivity of CO 2 ER on Pd. This article discusses the relationship between the selectivity and hydrogen adsorption on the Pd nanoparticles/carbon (Pd/XC72) catalyst through two kinds of systems: gas diffusion electrode (GDE) and rotating ring disk electrode (RRDE). The main product of the CO 2 ER on Pd/XC72 is changed from formate to CO when both the terrace and step sites of Pd particles are under a low coverage of adsorbed H atoms. In addition, the progress of CO self-poisoning on the Pd/XC72 catalyst and the peak corresponding to the oxidation of COOH * on the Pt ring electrode are clearly observed by the electrochemical analysis methods. The high selectivity of CO generation from the CO 2 ER on the Pd/XC72 catalyst is attributed to the progressive adsorption of CO which inhibits the participation of H ads during the CO 2 ER.