High-Throughput Screening of g-C 3 N 4 -Supported Single-Atom Catalysts for UDMH Dehydrogenation: A First-Principles Strategy

Unsymmetrical dimethylhydrazine (UDMH), a carcinogenic aerospace propellant, poses severe environmental threats due to its persistence and high toxicity. Despite the proven efficacy of electrocatalytic technology in degrading diverse organic contaminants, the development of electrocatalysts with high stability, activity, and selectivity for efficient UDMH degradation remains a critical and persistent challenge. Crucially, identifying promising candidates among the vast design space of potential catalysts is resource-intensive and time-consuming, and the process involves conventional experimental approaches. To overcome this bottleneck and accelerate discovery, we systematically investigate the potential of single transition metal (TM) atoms anchored on graphitic carbon nitride (g-C 3 N 4 ) monolayers─serving as TM- g -C 3 N 4 SACs─for UDMH degradation via first-principles high-throughput screening. This powerful computational approach enables the comprehensive evaluation of stability, adsorption behavior, and catalytic activity across 28 TM- g -C 3 N 4 candidates in a systematic and efficient manner. Remarkably, Os- g -C 3 N 4 emerges as the premier candidate, demonstrating robust UDMH capture via dual-terminal adsorption coupled with an ultralow dehydrogenation barrier (0.2702 eV, amino terminal) that is 59% lower than Pt-based systems. Crucially, this high activity coexists with exceptional stability (binding energy: −7.52 eV; dissolution potential: 0.84 V) and 41% cost reduction (90 vs 220 RMB/g). Mechanistic analysis reveals that metallic band formation post-Os loading and empty-orbital-mediated electron transfer synergistically activate UDMH, while orbital hybridization accelerates charge transfer. This work not only establishes Os- g -C 3 N 4 as a sustainable solution for rocket fuel remediation but also provides a universal SAC design blueprint transferable to diverse pollutant degradation systems.