• • The C-NPMG catalyst achieves overpotentials of 18.0 mV (0.5 M H2SO4), 42.2 mV (1 M KOH), and 88.0 mV (1 M PBS) at 10 mA cm−2, outperforming Pt benchmarks across all pH conditions; this pH universality is critical for integration into diverse electrolyzer systems without pH-specific catalyst replacement.
• • Stability exceeds 1000 h in alkaline electrolyte with negligible decay, addressing the chronic durability bottleneck of non-noble catalysts; this longevity is essential for industrial water electrolysis where catalyst replacement costs dominate operational expenses.
• • The nanoporous architecture and crystallite-amorphous interfaces lower the H2 desorption energy barrier, as confirmed by computational analysis; this mechanistic insight enables rational design of high-activity MG catalysts beyond trial-and-error.
• • The hierarchical super-hydrophilic/super-hydrophobic wettability optimizes mass transport and corrosion resistance, a dual function that reduces ohmic losses and extends catalyst lifetime, directly impacting energy efficiency and maintenance cycles in practical electrolyzers.