Au/Pb Interface Allows the Methane Formation Pathway in Carbon Dioxide Electroreduction

Abstract

The electrochemical conversion of carbon dioxide (CO2) to high-value chemicals is an attractive approach to create an artificial carbon cycle. Tuning the activity and product selectivity while maintaining long-term stability, however, remains a significant challenge. Here, we study a series of Au–Pb bimetallic electrocatalysts with different Au/Pb interfaces, generating carbon monoxide (CO), formic acid (HCOOH), and methane (CH4) as CO2 reduction products. The formation of CH4 is significant because it has only been observed on very few Cu-free electrodes. The maximum CH4 formation rate of 0.33 mA cm–2 was achieved when the most Au/Pb interfaces were present. In situ Raman spectroelectrochemical studies confirmed the stability of the Pb native substoichiometric oxide under the reduction conditions on the Au–Pb catalyst, which seems to be a major contributor to CH4 formation. Density functional theory simulations showed that without Au, the reaction would get stuck on the COOH intermediate, and without O, the reaction would not evolve further than the CHOH intermediate. In addition, they confirmed that the Au/Pb bimetallic interface (together with the subsurface oxygen in the model) possesses a moderate binding strength for the key intermediates, which is indeed necessary for the CH4 pathway. Overall, this study demonstrates how bimetallic nanoparticles can be employed to overcome scaling relations in the CO2 reduction reaction.

The Effect of the Coordination Environment of Atomically Dispersed Fe and N Co‐doped Carbon Nanosheets on CO2 Electroreduction

“…[8][9][10] The utilization of noble-metal catalysts for electroreduction of CO 2 to CO has made excellent progress, such as Au, Ag. [11][12][13] It is well known that the scarcity and cost of precious metals limit their industrial applications. To date, Cu-based catalysts have most abundant product (e. g., HCOOH, CH 3 CH 2 OH, C 2 H 6 , C 2 H 4 ) in the prior reports.…”

“…In recent years, a large number of efforts have been used in the studies of electrocatalysts with excellent properties [8–10] . The utilization of noble‐metal catalysts for electroreduction of CO 2 to CO has made excellent progress, such as Au, Ag [11–13] . It is well known that the scarcity and cost of precious metals limit their industrial applications.…”

Recent Progress in Electrocatalytic Methanation of CO2 at Ambient Conditions

“…In addition, Au centers play an critical role in the final steps in the CH 4 formation as shown in Figure 11c. [ 125 ]…”

“…c) The pathway for electrochemical CO 2 RR to CH 4 on Pb-Au system with 3% Au and O impurities. Reproduced with permission [125]. Copyright 2020, American Chemical Society.…”

Recent Advances in Interface Engineering for Electrocatalytic CO2 Reduction Reaction

“…Generally speaking, Au tends to be active to produce CO [123][124][125]. But its selectivity can be adjusted by introducing different second metals or manipulating their crystal phase [99,104,[126][127][128]. For example, Chen et al prepared the high-purity 4H Au@Cu and the heterophase 4H/fcc Au@Cu via the facile epitaxial growth method under ambient conditions (Fig.…”