AbstractPhotocatalytic hydrogen production by means of water splitting has attracted significant attention to convert solar energy into chemical energy. In this present study, a facile one‐step cation exchange approach was used to prepare CuxS decorated on CdS nanorods (CuxS/CdS NRs, x=1–2) for enhanced photocatalytic hydrogen production in water under visible light irradiation (λ>420 nm). Under optimal conditions, the highest H2 production rate achieved was ≈111 μmol h−1 and the apparent quantum yield reached ≈7 %. Efficient transfer processes of photogenerated charge carriers from CdS to CuxS, which can be attributed to the uniform distribution of CuxS on the CdS surface, were confirmed by steady‐state photoluminescence (PL) spectra and time‐resolved photoluminescence spectra. All the results indicate that this low‐cost cation exchange reaction is a promising method to construct an efficient system for photocatalytic hydrogen evolution.