Valorization of Plastic Waste Into Hydrogen: Ni–Co/Al2O3–ZrO2 Nanocatalyst for Efficient Steam Reforming of Low‐Density Polyethylene (LDPE)

Why It Matters

The technology offers a dual solution to plastic waste and clean‑hydrogen supply, supporting circular economy goals and decarbonization efforts. Its high efficiency and low coke propensity make it attractive for industrial scale‑up.

Key Takeaways

• Solvent-assisted steam reforming converts LDPE to hydrogen
• Ni–Co/Al₂O₃–ZrO₂ catalyst achieves 95% conversion
• Hydrogen yield reaches 92.7% with minimal coke
• Optimal S/C 9, 500 °C, GHSV 810 h⁻¹
• Bimetallic synergy improves kinetics and stability

Pulse Analysis

Plastic waste, especially low‑density polyethylene, continues to burden landfills and oceans, while global hydrogen demand surges as economies decarbonize. Converting polymeric carbon into clean fuel aligns with both waste‑reduction and energy‑transition goals. Recent research demonstrates that a solvent‑assisted steam reforming route can homogenize LDPE feed, enabling efficient catalytic processing that was previously limited by polymer melting and mass‑transfer constraints. Moreover, the use of ethylene glycol as a dispersing medium avoids high‑temperature melting, reducing energy input.

The study employs a 20 wt % Ni–Co/Al₂O₃–ZrO₂ nanocatalyst prepared by sol‑gel and wet impregnation, delivering a surface area of 136 m² g⁻¹ and strong metal‑support interaction. Under optimal conditions—steam‑to‑carbon ratio of 9, temperature 500 °C, and GHSV 810 h⁻¹—the system achieved 95 % LDPE conversion, 92.7 % hydrogen yield, and 97.6 % selectivity, while coke formation remained negligible. The catalyst’s thermal stability, confirmed by TGA‑DSC up to 600 °C, ensures prolonged operation without sintering. Compared with earlier PET or ethylene‑glycol reforming reports, the hydrogen yield improves by 5–10 %, underscoring the synergistic effect of nickel and cobalt in accelerating reforming kinetics and stabilizing the catalyst.

If scaled, this technology could integrate plastic waste streams into existing hydrogen infrastructure, reducing reliance on fossil‑derived steam reforming feedstocks. The low coke propensity simplifies reactor design and extends catalyst life, lowering operational costs. However, commercial deployment will require robust solvent recovery, feedstock preprocessing, and life‑cycle assessments to ensure net environmental benefits. Policy incentives for carbon‑negative fuels and plastic‑to‑hydrogen projects could accelerate investment, making the process economically viable. Nonetheless, the demonstrated performance positions solvent‑assisted LDPE reforming as a promising bridge between circular plastics management and the emerging green hydrogen economy.