Graphene-based catalyst for CO2 reduction: The critical role of solvents in materials design

• Published in: Journal of catalysis 2021-12, Vol.404, p.512-517
• Main Authors: Ozden, Sehmus, Delafontaine, Laurent, Asset, Tristan, Guo, Shengyuan, Filsinger, Kai A, Priestley, Rodney D., Atanassov, Plamen, Arnold, Craig B.
• Format: Article
• Language: English
• Subjects: Catalyst Design; CO2 Reduction; Defect-density; Graphene; Solvent Affect
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2021.10.014

[Display omitted] •We have reported the key role of solvent species on designing rGO supported CuNP composite structures for CO2RR activity.•Water, GBL, EG, EtOH and DMF have been used as solvents for the synthesis of the rGO-CuNP composite structure.•We reveal that solvents play a key role in tuning interlayer spacing of rGO sheets, defect density, morphology and CuNP yield in rGO-CuNP composite samples. The optimal material should exhibit large d-spacing, high defect density, high surface/porous morphology, and high CuNP yield.•Our findings indicate that DMF provides the most favorable combination of materials properties as compared to water, EG, EtOH, and GBL for the synthesis of rGO supported CuNP catalysts for highly efficient and selective CO2 reduction. The catalytic reduction of carbon dioxide (CO2) to hydrocarbon fuels offers a tremendous opportunity for a transformational impact on both global energy and environmental sustainability. To enhance the CO2 reduction process, the design and synthesis of novel and efficient catalytic materials with control-over properties are needed. The solvent used in the synthesis of these materials can play a crucial role in tailoring the material properties resulting in changes to their catalytic performance. However, the field still lacks a systematic analysis of the specific effect for different solvents. Here, we report the role of water, ethanol (EtOH), ethylene glycol (EG), Dimethylformamide (DMF), and γ-Butyrolactone (GBL) on the synthesis of reduced graphene oxide (rGO)-copper nanoparticles (CuNP) electrocatalysts used in CO2 reduction reactions (CO2RR). As these solvents contain different terminal groups and molecular sizes, we observed a variation in the d-spacing of the rGO, surface area, nanoparticle yield, and defect density, and characterized the corresponding change in the CO2RR activity. The use of DMF results in higher porosity, d-spacing, yield of CuNP, surface area and defect density which lead to comparatively higher efficiency and selectivity of and selectivity of 19.5 % and 28.4 % for formate and CO, respectively.