Interfacial Water Reorganization via Polyethyleneimine‐Functionalization for Enhanced Alkaline Hydrogen Evolution on Single‐Atom Platinum Anchored on Reduced Graphene Oxide

Why It Matters

By overcoming the sluggish proton transfer in alkaline media, this low‑Pt, high‑efficiency catalyst could reduce costs and boost scalability of green hydrogen production.

Key Takeaways

• PEI functionalization creates hydrogen-bonded water chain
• Overpotential 32 mV at 10 mA cm⁻²
• Tafel slope 51 mV dec⁻¹, charge resistance 2.5 Ω
• Primary amines anchor Pt atoms; secondary amines deliver protons
• Semi-linear Pt sites adsorb up to four H⁺ ions

Pulse Analysis

Alkaline water electrolysis promises cheaper, more durable hydrogen generation than acidic systems, yet its kinetics are hampered by slow proton transfer at the electrode‑electrolyte interface. Conventional catalysts rely on high metal loadings to compensate for this barrier, inflating material costs and complicating scale‑up. Recent research emphasizes interface engineering—modifying the local water structure and electric field—to create more favorable pathways for hydrogen evolution, a strategy that aligns with broader sustainability goals.

The RGO‑PEI/Pt1 catalyst exemplifies this approach by integrating single‑atom platinum onto a reduced graphene oxide sheet functionalized with polyethyleneimine. The PEI chains introduce primary amines that securely bind Pt atoms, preventing aggregation, while secondary amines form a hydrogen‑bonded network with interfacial water molecules. This network acts as a proton conduit, effectively lowering the activation energy for the rate‑determining step. Electrochemical tests reveal a striking overpotential of 32 mV at 10 mA cm⁻² and a Tafel slope of 51 mV dec⁻¹, metrics that rival or surpass many bulk‑metal catalysts despite using only trace amounts of platinum.

The implications extend beyond a single material breakthrough. Demonstrating that atomic‑scale Pt can be stabilized and its activity amplified through interfacial hydration opens a pathway for designing ultra‑low‑loading electrocatalysts across various reactions. Industries targeting large‑scale green hydrogen can leverage such designs to cut capital expenditures and improve system longevity. Moreover, the dual‑function concept—combining active‑site stabilization with water‑structuring additives—offers a versatile template for future research, potentially accelerating the commercialization of cost‑effective, high‑performance alkaline electrolyzers.