Theoretical exploration of bare and oxygen-functionalized Ti3C2 clusters for catalytic NH3 production

• Published in: Journal of chemical sciences (Bangalore, India) India), 2023-05, Vol.135 (2), Article 48
• Main Authors: Saha, Sougata, Ghoshal, Sourav, Sarkar, Pranab
• Format: Article
• Language: English
• Subjects: Chemical Reactivity and Biological Systems; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Interplay of Structure and Dynamics in Reaction Pathways; Regular Article
• ISSN: 0973-7103; 0973-7103
• DOI: 10.1007/s12039-023-02169-y

In this work, we performed high-level quantum chemical calculations to understand the comparative efficiency of Ti 3 C 2 and oxygen-functionalized Ti 3 C 2 (Ti 3 C 2 O 2 ) clusters for the catalytic conversion of N 2 to NH 3 . The global minima structures of N 2 -free and N 2 -adsorbed cluster were predicted using the ABC algorithm. Accordingly, N 2 can be adsorbed on Ti atoms in a side-on fashion. Binding energy, Wiberg bond index, and Bader charge analyses suggest that the N 2 -binding ability of the Ti 3 C 2 O 2 cluster is far better than that of the Ti 3 C 2 cluster. Relative free energy diagrams indicate that cluster-catalyzed NH 3 synthesis prefers to follow the distal pathway. The calculation of the energetic span model concludes that catalytic conversion of N 2 to NH 3 on Ti 3 C 2 O 2 possesses a lower effective activation barrier than that on the Ti 3 C 2 cluster, which implies that the Ti 3 C 2 O 2 is a more efficient catalyst than Ti 3 C 2 for the synthesis of NH 3 . Moreover, from the comparison with other metal clusters like V 3 C 2 O 2 and Nb 3 C 2 O 2 , we find that although the latter cluster possesses comparatively less energy span N 2 -philicity of Ti 3 C 2 O 2 is found to be far higher than that of Nb 3 C 2 O 2 cluster. Thus, the present study will provide a molecular-level understanding of improved N 2 reduction efficiency of the Ti 3 C 2 cluster through O-functionalization. Graphical Abstract Herein, we have performed quantum chemical calculations to understand the comparative efficiency of Ti 3 C 2 and oxygen-functionalized Ti 3 C 2 (Ti 3 C 2 O 2 ) clusters for the catalytic conversion of N 2 to NH 3 . We found that oxygen functionalization can dramatically enhance the N 2 reduction efficiency of the Ti 3 C 2 cluster.