Suppressing Charge Recombination via Cu‐Induced Hole Trap in CdS Nanorods for Enhanced Hydrogen Evolution

Solar‐driven hydrogen production stores renewable energy chemically but suffers from efficiency limitations due to the slow hole transport‐dominated recombination, which caused by high valence band degeneracy and hole effective mass. Targeted hole trap regulation is essential to minimize these losses and enhance photocatalytic H 2 evolution performance for practical applications. This study addresses this challenge via a metal‐doping strategy, fabricating Cu‐doped CdS nanorods via a mature hydrothermal method to promote hole trap and realizing efficient carrier separation. Structural analyses confirm Cu atoms are uniformly dispersed on the CdS without altering its hexagonal wurtzite structure. Meanwhile, with the Cd 3d peak shifting to higher binding energy by 0.2 eV and the S 2p peak shifting by 0.1 eV, it reveals the lattice contraction and valence band electronic rearrangement induced by Cu doping. Kinetics characterizations reveal that Cu doping reduces the trap‐assisted recombination while simultaneously facilitating the hole capture to extend charge carrier lifetimes. Ultimately, Cu@CdS yields a 2.3‐fold enhanced H 2 evolution rate compared with pristine CdS, achieving 6.8 mmol g −1 h −1 . This work establishes a doping framework to optimize hole trap dynamics, overcoming carrier recombination bottlenecks.