Oxocarbon-derived porous carbonaceous materials for electrocatalysis

The rising global demand for efficient energy conversion technologies underscores the necessity for advanced carbon materials with specific structural and functional attributes. Porous carbon materials, characterized by their high specific surface area and tunable pore structures, are particularly promising for electrocatalysis. However, the rational design of functional carbons, the development of new synthesis routes, and the exploration of the structure-activity relationship still remain challenging. This dissertation contributes to the development of novel oxygen-doped functional porous carbon materials derived from diverse oxocarbons. It focuses on tailoring their structures and properties to enhance the electrocatalytic performance, amming to elucidate the structure-activity relationships and provide new insights of developing advanced carbonaceous materials for electrocatalysis. In Chapter 2, red carbon oligomer was used as the precursor for the synthesis of carbons. This precursor without inactive C-H bond can undergo crosslinking with the only release of edge CO2 groups, facilitating the formation of porous oxocarbons at temperatures as low as 400°C without templating agents. Owing to the microporous structures, the carbon materials act as metal-free electrocatalysts presenting good performance for oxygen reduction reaction. Additionally, it enables effective crosslinking of the precursor on non-conductive surfaces at low temperatures, yielding thin conductive carbon films resistant to corrosive environments. SnCl2 was used as salt melt in Chapter 3 to further lower the temperature requirement of thermal condensation of red carbon oligomer, resulting in higher specific surface area and porosity. SnCl2 as a reactive salt melt can intercept the oxygen atoms of red carbon, causing the removal of oxygen atoms and favoring the thermal condensation process. Moreover, the in-situ formation of SnO2 nanoparticles acted as hard templates, further leading to highly porous structures. Such pore formation mechanism was confirmed also applicable for other oxygen-rich precursors. The obtained carbons with oxygen functionalities presented high activity and selectivity for electrocatalytic nitrate hydrogenation to ammonia, overpassing other carbon materials, even the carbon-supported metals. In Chapter 4, THQ molecule, an oxygen-rich compound, was utilized as a precursor for the preparation of oxocarbons and oxocarbon-supported Cu SACs in the presence of MgCl2∙6H2O. The interaction between MgCl2∙6H2O and the hydroxyl groups of THQ contributed to the specific growth of the structures, leading to homogeneous 2D flake structures. Moreover, Mg can intercept oxygen from the THQ molecule, forming MgO secondary hard templates and resulting in mesoporous structures with a high specific surface area of 1177 m²/g at 600°C. Furthermore, THQ served as a ligand in the synthesis of THQ-Cu MOFs, which were subsequently employed to design oxygen-stabilized Cu SACs on oxygen-rich carbon supports. The Cu SACs exhibited high activity in glycerol oxidation, achieving high Faradaic efficiency and selectivity, superior to many other Cu-based catalysts, which suggested the promising utilization as a catalyst for converting byproducts into valuable formic acid.

Author dc:creator

• Zheng, Xinyue

Advisors dc:contributor.advisor

• Thomas, Arne
• Antonietti, Markus

Licence dc:rights.uri

• https://creativecommons.org/licenses/by/4.0/

Language dc:language.iso

en

Identifier URI

https://doi.org/10.14279/depositonce-22067

OAI identifier oai:identifier

oai:depositonce.tu-berlin.de:11303/23253