Wenlong Zhen

The growing accumulation of poly(ethylene terephthalate) (PET) waste and the increasing demand for clean hydrogen call for integrated electrochemical strategies. Ethylene glycol oxidation reaction (EGOR), derived from PET hydrolysis, offers a thermodynamically favorable alternative to the sluggish oxygen evolution reaction (OER) and can be coupled with the hydrogen evolution reaction (HER) to simultaneously produce value-added chemicals and H2. This review provides a system-level overview of EGOR||HER paired electrolysis, spanning reaction fundamentals, catalyst design, cell configuration, and future challenges. First, the competing EGOR pathways toward C1 products (such as formate/formic acid) and C2 products (such as glycolate/glycolic acid) are discussed. Key energetic descriptors, including cell voltage, overpotential, Faradaic efficiency, and energy efficiency, are then summarized to clarify the advantages of replacing OER with EGOR. Recent advances in catalysts, including precious metals, transition-metal compounds, metal–organic frameworks (MOFs), organic catalysts, and hybrid systems, are reviewed with attention to their bifunctional or compatible activity for EGOR and HER. Reactor design is further discussed by comparing single-cell and dual-cell H-type reactors with membrane-free and membrane-separated flow-cell reactors, emphasizing their different roles in mass transport, product separation, and scale-up feasibility. Finally, remaining challenges and future directions are proposed, including C1/C2 selectivity, downstream separation, impurity tolerance, catalyst durability, and practical reactor optimization. This review aims to guide the development of efficient EGOR-assisted hydrogen production systems for sustainable PET electro-upcycling.

Photocatalytic hydrogen evolution from water is a sustainable approach to producing clean energy and promoting sustainable development. However, the low efficiency of photocatalysts under visible light and even near-infrared irradiation remains the current bottleneck in photocatalytic overall water splitting (POWS). Herein, we introduce an Al₂O₃/InP/Al photocatalyst with high efficiency and stability, which achieved an apparent quantum efficiency of 0.97% at 500 nm and operated for 10 h without significant performance decay. The high quantum efficiency and stability are attributed to the combination of the electron-rich Al reflective layer and Al₂O₃ protective layer coating, which synergistically facilitate charge separation. Additionally, the newly generated O₂ from water over the Al₂O₃/InP/Al photocatalyst was removed under reduced pressure, thus inhibiting InP photocorrosion and enabling POWS under visible light irradiation. This study offers valuable insights for the development of efficient solar photocatalysts for water splitting.