Symmetry‐Broken Au–Cu Heterostructures and their Tandem Catalysis Process in Electrochemical CO₂ Reduction

Abstract

Symmetry-breaking synthesis of colloidal nanocrystals with desired structures and properties has aroused widespread interest in various fields, but the lack of robust synthetic protocols and the complex growth kinetics limit their practical applications. Herein, a general strategy is developed to synthesize the Au-Cu Janus nanocrystals (JNCs) through the site-selective growth of Cu nanodomains on Au nanocrystals, which is directed by the substantial lattice mismatch between them, with the assistance of judicious manipulation of the growth kinetics. This strategy can work on Au nanocrystals with different architectures for the achievement of diverse asymmetric Au-Cu hybrid nanostructures. Of particular note, the obtained Au nanobipyramids (Au NBPs)-based JNCs facilitate the conversion of CO 2 to C 2 hydrocarbon production during electrocatalysis, with the Faradaic efficiency and maximum partial current density being 4.1-fold and 6.4-fold higher than those of their monometallic Cu counterparts, respectively. The excellent electrocatalytic performances benefit from the special design of the Au-Cu Janus architectures and their tandem catalysis mechanism as well as the high-index facets on Au nanocrystals. This research provides a new approach to synthesize various hybrid Janus nanostructures, facilitating the study of structure-function relationship in the catalytic process and the rational design of efficient heterogeneous electrocatalysts.

The Role of Roughening to Enhance Selectivity to C2+ Products during CO2 Electroreduction on Copper

“…We note here that it is unlikely that *OH actually binds to roughened Cu under CO2RR conditions, as it would have a very strong driving force to reduce to water; rather, ΔΩ OH serves as a descriptor for the formation of formate. Competition between formate and the C 1+ pathway highlight the success of tandem catalysis: − by utilizing a catalyst such as Ag which selectively reduces CO 2 to CO which then diffuses to Cu, the formate pathway is partially eliminated.…”

Symmetry-Reduced Metal Nanostructures Offer New Opportunities in Plasmonics and Catalysis

“…The potential of heterodimeric NPs as catalysts was revealed through the study of Au–Cu NPs for electrocatalytic reduction of CO 2 . Cu NPs have shown great promise as an electrocatalyst for CO 2 reduction, but poor selectivity persists. , To address this challenge, heterodimeric Au–Cu NPs were synthesized by overgrowth of Cu from bipyramidal Au seeds, where the large lattice mismatch between Au and Cu facilitated dimer formation (Figure A,B) . Au–Cu heterodimers from spherical Au seeds, core@shell Au@Cu NPs, Au nanobipyramids, Cu nanospheres, and mixtures of the two were also synthesized for comparison.…”

“…Typically, symmetry reduction is achieved during seed-mediated methods where there is a large lattice mismatch between the seeds and depositing material, the supply of depositing atoms is low (i.e., low supersaturation), nanocrystal surfaces (or seeds) are asymmetrically passivated, or seeds are confined at interfaces . Symmetry-reduced NPs prepared by these methods are proving useful for applications ranging from security devices to electrocatalysts. − …”

Seeded Growth of Gold–Copper Janus Nanostructures as a Tandem Catalyst for Efficient Electroreduction of CO2 to C2+ Products

“…[16a] However, to the best of our knowledge, limited research progress has been achieved in the case of Au-Cu combination. [17] Although the large lattice mismatch exists between the two metals, most Au-Cu products documented in literature adopted the core-shell or alloy structure. [18] We also noted that some of the previous studies reported the successful asymmetric growth observed in the synthesis of Au-Cu nanocrystals.…”