Sluggish kinetics of overall water splitting and high costs of sacrificial agent-dependent H₂ evolution have severely restricted the scale application of light-driven hydrogen production technology. The value-added oxidation of benzyl alcohol (BA) has emerged as an ideal candidate to circumvent the aforementioned obstacles. However, developing highly active photocatalysts is pivotal for efficient catalytic photo-redox. Herein, carbon (C)-heteroatoms were doped into the CdS lattice, and Au-cocatalyst was subsequently decorated to prepare the Au-decorated, C-doped CdS for achieving exceptional co-production of benzaldehyde (31.29 mmol·g^-1·h^-1) and H₂ (24.37 mmol·g^-1·h^-1), delivering an apparent quantum efficiency of 5.08% under 420 nm-photoirradiation. Density functional theory calculations revealed that the C-heteroatoms, leveraging their intrinsic electron-trapping effect, could rapidly accumulate photoexcited electrons from CdS, thereby acting as active sites for H₂ evolution. In contrast, the Au nanococatalyst, benefiting from its strong surface plasmon resonance effect, injected resonant electrons into CdS and served as the active center for BA oxidation. Experimental results provided direct evidences to validate the theoretical conclusions, while H isotope tracing further verified the synergy of the collaborative reaction process. This study proposes a dual-mechanism strategy for improving the redox photoactivity of CdS photocatalysts by integrating heteroatom-doping and surface metal cocatalysis.