Cooperative Copper Single-Atom Catalyst in 2D Carbon Nitride for Enhanced CO₂ Electrolysis to Methane

Author(s):Show less -

Roy, Soumyabrata ; Li, Zhengyuan ; Chen, Zhiwen ; Mata, Astrid Campos ; Kumar, Pawan ; Sarma, Saurav Ch. ; Teixeira, Ivo F. ; Silva, Ingrid F. ; Gao, Guanhui ; Tarakina, Nadezda V. ; Kibria, Md Golam ; Singh, Chandra Veer ; Wu, Jingjie ; Ajayan, Pulickel M.

• Document type: Journal article
• Source: Advanced Materials; v. 36, n. 13, p. 13-pg., 2024-01-06.

Abstract

Renewable-electricity-powered carbon dioxide (CO2) reduction (eCO(2)R) to high-value fuels like methane (CH4) holds the potential to close the carbon cycle at meaningful scales. However, this kinetically staggered 8-electron multistep reduction suffers from inadequate catalytic efficiency and current density. Atomic Cu-structures can boost eCO(2)R-to-CH4 selectivity due to enhanced intermediate binding energies (BEs) resulting from favorably shifted d-band centers. In this work, 2D carbon nitride (CN) matrices, viz. Na-polyheptazine (PHI) and Li-polytriazine imides (PTI), are exploited to host Cu-N-2 type single-atom sites with high density (approximate to 1.5 at%), via a facile metal-ion exchange process. Optimized Cu loading in nanocrystalline Cu-PTI maximizes eCO(2)R-to-CH4 performance with Faradaic efficiency (FECH4) of approximate to 68% and a high partial current density of 348 mA cm(-2) at -0.84 V vs reversible hydrogen electrode (RHE), surpassing the state-of-the-art catalysts. Multi-Cu substituted N-appended nanopores in the CN frameworks yield thermodynamically stable quasi-dual/triple sites with large interatomic distances dictated by the pore dimensions. First-principles calculations elucidate the relative Cu-CN cooperative effects between the matrices and how the Cu local environment dictates the adsorbate BEs, density of states, and CO2-to-CH4 energy profile landscape. The 9N pores in Cu-PTI yield cooperative Cu-Cu sites that synergistically enhance the kinetics of the rate-limiting steps in the eCO(2)R-to-CH4 pathway. (AU)

• FAPESP's process: 21/12394-0 - Sustainable synthetic methods employing catalysis, benign solvents, safer reagents, and bio-renewable feedstock
• Grantee: Arlene Gonçalves Corrêa
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 21/11162-8 - Multi-user equipment approved in grant 2020/14741-6: GC-MS/FID/TCD (2 injetores+Loop+Sistema valvulado)
• Grantee: Ivo Freitas Teixeira
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 20/14741-6 - Graphitic carbon nitrides as platforms for single-atom photocatalysis: moving towards design principles for improved performance
• Grantee: Ivo Freitas Teixeira
• Support Opportunities: Research Grants - Young Investigators Grants