Molybdenum bound nitrogen‐doped graphene catalyst for reduction of N2 to NH3 and NH2NH2, using FLP as a co‐catalyst: A DFT study

• Published in: Applied organometallic chemistry 2022-05, Vol.36 (5), p.n/a
• Main Authors: Sivan, Akhil K., Thomas, Jisha Mary, Jeyakumar, Thayalaraj Christopher, Sivasankar, Chinnappan
• Format: Article
• Language: English
• Subjects: DFT (density functional theory); dinitrogen; FLP (frustrated Lewis pair); molybdenum; nitrogen‐doped graphene
• ISSN: 0268-2605; 1099-0739
• DOI: 10.1002/aoc.6644

Chemists have long been pursuing the aim of synthesising practically viable low temperature catalysts with high stability, activity and selectivity towards the generation of ammonia under less expensive reaction conditions by using H2 and N2. In this regard, we have used molybdenum bound nitrogen‐doped graphene as a catalyst in the present computational investigation. We developed a new concept of the Frustrated Lewis Pair [AH]+[BH]− (FLP‐H2), which can be used as a source of hydrogen to functionalise the coordinated dinitrogen into ammonia. Furthermore, the utilisation of FLP‐H2 can prevent the competition in binding of N2 and H2 with Mo centre and enable the product formation. Our computed thermodynamic and kinetic barriers clearly reveal that the molybdenum bound nitrogen‐doped graphene can be used as a catalyst to activate and functionalise the dinitrogen. In the proposed catalytic cycle, H+ and H− can be added in an alternate manner using the FLP‐H2 source to yield NH3 and NH2NH2. Some thermodynamically viable penta‐coordinated [M]H intermediates have also been identified in the current study. DFT calculations have been carried out to understand the possibility of converting dinitrogen into ammonia using dihydrogen. We developed a new concept where the frustrated Lewis pair can be used to activate the H2 ([AH]+[BH]− (FLP‐H2)) along with molybdenum bound nitrogen‐doped graphene which acts as a catalyst, subsequently functionalising the coordinated dinitrogen can produce ammonia and hydrazine. The mechanistic approach, followed by the addition of H+ and H− using the FLP source, results in the formation of NH3/NH2NH2.