Site-Specific Heteroatoms Doped Graphdiyne as Metal-Free Electrocatalysts for Nitrogen Reduction

Descripción del proyecto

Catalizadores de alto rendimiento para reacciones de reducción del nitrógeno

La reacción electrocatalítica de reducción del nitrógeno es una alternativa sostenible para la producción de amoníaco. Sin embargo, su uso generalizado se ve obstaculizado por la poca eficacia de los electrocatalizadores basados en metales. Las estructuras de N y BC3 (un compuesto parecido al grafito) han demostrado ser los sitios más activos para la síntesis del amoníaco, aunque no existen en la actualidad métodos eficaces para lograr el dopaje específico del sitio. El proyecto GDYNRR, financiado por las Acciones Marie Skłodowska-Curie, se propone dopar de forma selectiva átomos de N y BC3 en grafidina (GDY, por sus siglas en inglés), un alótropo de carbono lamelar, para obtener catalizadores muy selectivos destinados a la reducción electrocatalítica de nitrógeno. El trabajo se centrará en el estudio de cómo las estructuras de N y BC3 afectan a las propiedades de la GDY.

Objetivo

Eletrocatalytic nitrogen reduction reaction (NRR) has rencetly emerged as a sustainable alternative for ammonia production. However, the metal-based electrocatalysts for NRR suffer from low efficienciess due to the competing hydrogen evolution reaction. Heteroatoms doped carbon based metal-free catalysts feature weak integration with hydrogen, making them potential candidates for NRR. The NRR activity depends closely on the the form of doped atoms. The pyridinic N atoms and BC3 structure are demonstrated as the most active sites for ammonia synthesis. However, for widely researched carbon materials, it is difficult to selectively dope a sufficient amount of site-specific pyridinic N or BC3 atoms.
As a lamellar carbon allotrope, graphdiyne (GDY), constituted by sp- and sp2- carbon atoms, is a great breakthrough. The high energy of sp-hybridization of acetylenic linkages enables the arbitrary angle rotation of π/π* perpendicular to the axis, endowing it a possibility to point towards N2. Another important feature of GDY is that it can be synthesized in solution via bottom-up method. A controllable heteroatoms doping method using a monomer design strategy, provides an ideal solution to achieve the site-specific doping. However, the attempt to design site-specific pyridinic N or BC3 atoms doped GDYs for electrocatalytic NRR has never been reported.
The objective of this project is to selectively dope the site-specific pyridinic N and BC3 atoms into GDY to achieve the high performance and selectivity towards NRR. The influence of the pyridinic N and BC3 structure on the properties of GDY will be studied. Afterwards, the prepared site-specific heteroatoms doped GDYs will be used as electrocatalysts for NRR. Owing to the exact doping structure, the catalytic mechanisms for NRR will be recognized. At last, the optimal heteroatoms doped GDY electrode will be integrated in a functional N2 reduction device to demonstrate the overall N2 reduction in practical conditions.