Rare‐Earth Metal–Organic Framework/CdS Heterostructures for Highly Efficient Photocatalytic Hydrogen Evolution

Rare‐earth metal–organic frameworks (RE‐MOFs) featuring tunable coordination environments and unique 4f electronic configurations hold great potential for photocatalytic applications. Nevertheless, their efficiency is often limited by rapid charge recombination. Herein, a series of RE‐MOFs were synthesized via solvothermal reactions using 2′‐amino‐[1,1′:4′,1″‐terphenyl]−3,3″,5,5″‐tetracarboxylic acid (NH 2 ‐H 4 TPTC) as the organic linker and erbium/holmium (Er 3+ /Ho 3+ ) as metal nodes and further integrated with CdS nanoparticles via a precipitation strategy to construct RE‐MOF/CdS heterostructures. Comprehensive characterization verified the successful formation and stability of the composites. Under visible‐light irradiation from a 300 W xenon lamp over 3 h, both Er‐NH 2 ‐TPTC/CdS and Ho‐NH 2 ‐TPTC/CdS exhibited significantly enhanced photocatalytic hydrogen evolution compared with pristine CdS. The optimized Ho‐NH 2 ‐TPTC/CdS (20 wt%) composite achieved a hydrogen evolution rate of 11 408 μmol·g −1 , representing an 8.6‐fold enhancement over pristine CdS. Mechanistic analyses revealed that the intimate RE–MOF/CdS interface facilitates efficient charge separation and transfer, thereby suppressing electron–hole recombination. This study demonstrates a rational strategy for constructing high‐performance RE‐MOF‐semiconductor heterostructures and provides new insight into the design of rare‐earth‐based photocatalysts for solar hydrogen production.