| Full text | |
| Author(s): |
Messias, Igor
;
Winkler, Manuel E. G.
;
Costa, Gabriel F.
;
Mariano, Thiago
;
Souza Junior, Joao Batista
;
Neckel, Itamar Tomio
;
Figueiredo, Marta C.
;
Singh, Nirala
;
Nagao, Raphael
Total Authors: 9
|
| Document type: | Journal article |
| Source: | ACS APPLIED ENERGY MATERIALS; v. 7, n. 19, p. 11-pg., 2024-10-02. |
| Abstract | |
Nitrate electroreduction reaction (NO3RR) to ammonia (NH3) still faces fundamental and technological challenges. While Cu-based catalysts have been widely explored, their activity and stability relationship are still not fully understood. Here, we systematically monitored the dynamic alterations in the chemical and morphological characteristics of Cu2O nanocubes (NCs) during NO3RR in an alkaline electrolyte. In 1 h of electrolysis from -0.10 to -0.60 V vs RHE, the electrocatalyst achieved the maximum NH3 faradaic efficiency (FE) and yield rate at -0.3 V (94% and 149 mu mol h(-1) cm(-2), respectively). Similar efficiency could be found at a lower overpotential (-0.20 V vs RHE) in long-term electrolysis. At -0.20 V vs RHE, the catalyst FE increased from 73% in the first 2 h to similar to 90% in 10 h of electrolysis. Electron microscopy revealed the loss of the cubic shape with the formation of sintered domains. In situ Raman, X-ray diffraction (XRD), and in situ Cu K-edge X-ray absorption near-edge spectroscopy (XANES) indicated the reduction of Cu2O to oxide-derived Cu-0 (OD-Cu). Nevertheless, a remaining Cu2O phase was noticed after 1 h of electrolysis at -0.3 V vs RHE. This observation indicates that the activity and selectivity of the initially well-defined Cu2O NCs are not solely dependent on the initial structure. Instead, it underscores the emergence of an OD-Cu-rich surface, evolving from near-surface to underlying layers over time and playing a crucial role in the reaction pathways. By employing online differential electrochemical mass spectrometry (DEMS) and in situ Fourier transform infrared spectroscopy (FTIR), we experimentally probed the presence of key intermediates (NO and NH2OH) and byproducts of NO3RR (N-2 and N2Hx) for NH3 formation. These results show a complex relationship between activity and stability of the nanostructured Cu2O oxide catalyst for NO3RR. (AU) | |
| FAPESP's process: | 19/18847-6 - Ammonia electrochemical synthesis from nitrate reduction at metal oxides: an in operando investigation |
| Grantee: | Gabriel Floriano Costa |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |
| FAPESP's process: | 21/08868-6 - Tandem dissipative electrodes applied in the reduction of carbon dioxide to the formation of C2+ products |
| Grantee: | Raphael Nagao de Sousa |
| Support Opportunities: | Program for Research on Bioenergy (BIOEN) - Regular Program Grants |
| FAPESP's process: | 23/10045-3 - Co3O4/CuO/Cu electrodes for nitrate electroreduction |
| Grantee: | Manuel Edgardo Gomez Winkler |
| Support Opportunities: | Scholarships in Brazil - Support Program for Fixating Young Doctors |
| FAPESP's process: | 23/02841-4 - Co3O4/CuO/Cu electrodes for nitrate electroreduction |
| Grantee: | Raphael Nagao de Sousa |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 22/14169-6 - Electrocatalytic synthesis of ammonia from nitrate reduction: the role of copper and its oxides as efficient catalysts |
| Grantee: | Raphael Nagao de Sousa |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 22/01799-1 - Ammonia electrosynthesis from nitrate reduction: flow cell and in-situ Raman spectroscopic studies |
| Grantee: | Gabriel Floriano Costa |
| Support Opportunities: | Scholarships abroad - Research Internship - Doctorate (Direct) |
| FAPESP's process: | 17/11986-5 - Generation and storage of New Energy: bringing technological development for the country |
| Grantee: | Ana Flávia Nogueira |
| Support Opportunities: | Research Grants - Research Centers in Engineering Program |
| FAPESP's process: | 21/03321-9 - Controlling the structure of semiconductor nanoparticles: surface, defects, and properties |
| Grantee: | João Batista Souza Junior |
| Support Opportunities: | Regular Research Grants |