Computational screening of single-cluster catalysts anchored on g-C₃N₄ for nitroreduction of 3-nitro-1,2,4-trizole-5-one (NTO)

3-nitro-1,2,4-triazole-5-one (NTO) is widely used as an insensitive explosive in high-safety weapon systems; however, it poses significant environmental risks due to its high solubility and anionic nature. Despite 3-amino-1,2,4-triazole-5-one (ATO) has been identified as the key intermediate during NTO degradation, developing highly active and selective catalysts for the NTO to ATO process remains challenging. Using computational screening with density functional theory (DFT), ab initio molecular dynamics (AIMD) simulations, and enhanced sampling approach, this study presents a rational design among metal trimer (M₃, where M = Ag, Au, Cu, Ir, Os, Pt, Pd, Rh, and Ru) cluster anchored on N-vacancy and perfect graphitic carbon nitride (g-C₃N₄) as robust single-cluster catalysts (SCCs) with promising efficiency for NTO nitroreduction. Through a three-step process involving structural optimization, AIMD simulation, and enhanced sampling calculation, we found that Ru shows remarkable activity and selectivity for NTO nitroreduction, particularly in a solvent environment with a higher concentration of H. Notably, the Ru₃@1CN SCC demonstrates the ability to directly reduce NTO to ATO in the first two steps. This work opens new avenues for NTO nitroreduction in contamination control and production of functionalized chemicals, providing valuable guidance for selective hydrogenation of other nitro compounds as well.