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

Descrizione del progetto

Catalizzatori ad alte prestazioni per reazioni di riduzione dell’azoto

La reazione elettrocatalitica di riduzione dell’azoto è un’alternativa sostenibile per la produzione di ammoniaca. Tuttavia, il suo ampio utilizzo è ostacolato dalle basse efficienze degli elettrocatalizzatori a base di metallo. Le strutture N e BC3 (un composto simile alla grafite) hanno dimostrato di essere i siti più attivi per la sintesi dell’ammoniaca, ma attualmente non esistono metodi efficienti per ottenere un drogaggio sito-specifico. Finanziato dal programma di azioni Marie Skłodowska-Curie, il progetto GDYNRR prevede di drogare selettivamente atomi di N e BC3 in grafine, un allotropo lamellare del carbonio, per ottenere catalizzatori altamente selettivi per la reazione elettrocatalitica di riduzione dell’azoto. L’attenzione principale sarà posta sullo studio di come le strutture N e BC3 influenzano le proprietà del grafine.

Obiettivo

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.