A Red Brick‐Derived Fe2P‐Based Cocatalyst Sheet Enables Monolithic Photocatalysts for Efficient Solar Hydrogen Production

Why It Matters

The low‑cost, scalable monolithic design dramatically improves solar hydrogen efficiency while eliminating complex fabrication and expensive scaffolds, accelerating commercial deployment of renewable fuel technologies.

Key Takeaways

• Red brick transformed into Fe2P cocatalyst sheet
• Monolithic CdS-Fe2P/RB yields 7.7 mmol g⁻¹ h⁻¹ HER
• AQY reaches 30.5% at 420 nm, 3.2× higher
• Stable H2 output for 120 hours without decay
• Enables scalable panel reactors for solar hydrogen

Pulse Analysis

Photocatalytic water splitting has long been hampered by the reliance on powder‑suspension systems, which suffer from poor light harvesting, difficult recovery, and high material costs. Monolithic architectures address these shortcomings by integrating light‑absorbing semiconductors onto a continuous support, thereby enhancing photon utilization and simplifying reactor design. However, existing monoliths often require expensive substrates or additional cocatalyst loading steps, limiting their economic viability for large‑scale hydrogen generation.

The breakthrough reported here leverages an abundant construction material—red brick—as a source of iron oxides that are in‑situ phosphidated to form Fe2P active sites. This Fe2P/RB sheet acts simultaneously as a structural scaffold and an electron‑sink cocatalyst, promoting charge separation and providing abundant hydrogen‑evolution sites. When coupled with CdS particles, the monolith achieves a visible‑light HER rate of 7.7 mmol g⁻¹ h⁻¹ and an AQY of 30.5% at 420 nm, surpassing comparable powder systems by more than threefold. Moreover, the integrated sheet retains its performance for 120 hours, demonstrating exceptional durability under continuous illumination.

From an industry perspective, the use of a waste‑derived, low‑cost substrate dramatically reduces capital expenditures while delivering high catalytic efficiency. The planar geometry enables straightforward scaling into panel‑type reactors, facilitating modular deployment in solar farms or offshore platforms. This strategy not only lowers the barrier to commercial solar hydrogen production but also opens avenues for repurposing other abundant mineral wastes into high‑performance photocatalytic platforms, accelerating the transition toward a carbon‑neutral energy economy.