A strongly coupled cluster heterostructure with Pt–N-Mo bonding for durable and efficient H2 evolution in anion-exchange membrane water electrolyzers

Alkaline water electrolyzers promise to unlock terawatt-scale green hydrogen, yet their Achilles’ heel remains the cathode: sluggish water-splitting kinetics, Pt nanoparticles that ripen into inert clumps, and price tags that still hover above the US DOE target of US$2 kg⁻¹. Now, a China–US collaboration led by Prof. Zhuangjun Fan (China University of Petroleum) and Prof. Zhenhai Wen (Fujian Institute of Research on the Structure of Matter) delivers a Pt/Mo₂N cluster heterostructure on N-doped rGO that slashes overpotential, resists degradation for >500 h at 1.5 A cm^-2, and drives the levelized cost of hydrogen down to US$2.02 kg^-1—meeting the long-sought DOE benchmark.

Why This Catalyst Matters

• 11 mV at 10 mA cm^-2 – the lowest alkaline HER onset ever reported for a Pt-based system.
• 17.7 A mgPt^-1 mass activity – 10× commercial Pt/C.
• 500-h durability at industrial 1.5 A cm^-2 with <5 % potential drift.
• Techno-economic win – 1 MW plant model hits US$2.02 kg^-1, inside DOE corridor.

Engineering the “Nano-Scissors” Interface

1. Anderson Clusters as Atomic Glue

• PtMo₆ polyoxometalate precursor (1–2 nm) is nitrided at 800 °C to yield ~2 nm Pt/Mo₂N clusters tightly stitched by Pt–N–Mo bonds (EXAFS at 1.56 Å).
• Charge transfer from Pt to Mo₂N (Δ oxidation state +1.45) down-shifts the Pt d-band center (−2.73 eV), weakening H binding* while Mo sites anchor OH*—a molecular-scale “scissors” that cleaves H–OH in one stroke.

2. Operando Evidence

• Live Raman at −0.25 V vs RHE tracks the Mo–OH (795 cm^-1) and Pt–H (2328 cm^-1) fingerprints simultaneously, revealing a bifunctional Volmer-Tafel pathway akin to acidic kinetics.
• DFT snapshots: Volmer barrier drops from 0.93 eV on Pt(111) to 0.36 eV on Pt/Mo₂N; ΔG_H* moves to −0.07 eV—thermoneutral sweet-spot.

3. Device-Ready Performance

• AEMWE cell (Pt/Mo₂N–NrGO || NiFe LDH) delivers 1.0 and 2.0 A cm^-2 at only 1.66 V and 1.84 V at 80 °C—outperforming commercial Pt/C across the full temperature sweep.
• Energy efficiency peaks at 95 % (500 mA cm^-2) and stays above 88 % at 1 A cm^-2.
• Techno-economic model shows CAPEX falls 70 % from 100 to 2000 mA cm^-2 while OPEX remains dominated by electricity; optimum sits at 560 mA cm^-2 for the US$2.02 kg^-1 LCOH.

Toward Gigawatt Deployment

• Roll-to-roll spray coating already demonstrated on 12 × 2 cm² cells; scale-up roadmap targets m²-scale electrodes.
• Precursor is earth-abundant: Mo and N-rich urea cut noble-metal demand by 80 % versus state-of-art Pt/C.
• Next-gen roadmap: extend cluster strategy to seawater electrolysis and nitrate reduction—turning waste streams into hydrogen hubs.

Stay tuned as this cluster blueprint migrates from lab coin-cells to shipping-container electrolyzers, pushing green hydrogen past the tipping point.