Structure sensitivity and evolution of nickel-bearing nitrogen-doped carbons in the electrochemical reduction of CO2

DOI: 10.1021/acscatal.9b05333

Authors: Simon Büchele (ETH Zürich) , Antonio J. Martin (ETH Zürich) , Sharon Mitchell (ETH Zürich) , Frank Krumeich (ETH Zürich) , Sean M. Collins (University of Cambridge) , Shibo Xi (Agency for Science, Technology and Research (A*STAR)) , Armando Borgna (Agency for Science, Technology and Research (A*STAR)) , Javier Pérez-ramírez (ETH Zürich)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Catalysis

State: Published (Approved)
Published: February 2020
Diamond Proposal Number(s): 23504

Abstract: The emergence of nickel single-atoms on nitrogen-doped carbons as high-performance catalysts amenable to rationalization due to their well-defined structure could lead to applicable technologies for the electrocatalytic CO2 reduction reaction (eCO2RR). However, real materials are unlikely to display a uniform site structure, which limits the scope of current efforts focused on idealized models for future implementation. Here, we prepare distinct nickel entities (single atoms or nanoparticles) on nitrogen-doped carbons and evaluate them in eCO2RR. Single atoms demonstrate a characteristic high selectivity to CO. However, this is not altered by the presence of metal nanoparticles formed upon reducing the nitrogen content of the carrier. In contrast, nanoparticles incorporated via a colloidal route promote the parasitic hydrogen evolution reaction. In these systems, the CO selectivity evolves upon repeated exposure to potential, reaching values comparable to single atoms. By introducing CO stripping voltammetry as a characterization tool for this class of materials, we identify a decreased metallic surface, suggesting that the nanoparticle surface is altered by CO. The findings highlight the critical role of dynamic effects in catalyst design for eCO2RR.

Journal Keywords: Electrocatalytic CO2 reduction; Single-atom catalysis; Nickel speciation; Nitrogen-doped carbons; Structure-activity relationships

Subject Areas: Chemistry

Diamond Offline Facilities: Electron Physical Sciences Imaging Centre (ePSIC)
Instruments: E02-JEM ARM 300CF