We herein report a novel ternary CdS/reduced graphene oxide (RGO)fgraphitic carbon nitride (g-C3N4) hybrid photocatalyst for H-2 generation and degradation of atrazine (a potent herbicide) through Z-scheme electron transport. Based on energy band theory, two visible-light-active semiconductors, CdS-coupled RGO and exfoliated g-C3N4 nanosheets (NSs), were coupled to construct Z-scheme hybrids using a hydrothermal process. Compared with the bare photocatalysts, the as-prepared hybrid photocatalysts exhibited efficient H-2 generation and atrazine degradation activity owing to improved charge separation and photostability. As the electron mediator, RGO played an important role in accelerating electron transfer at the CdS/g-C3N4 interface via the Z-scheme electron transfer pathway. This Z-scheme charge transfer was verified using various techniques, including photoluminescence, transient photocurrent measurements, and determination of the photocatalyst band potentials. A suitable Z-scheme charge separation mechanism was proposed for the improved H-2 generation activity. The intermediates formed during atrazine decomposition were identified, and an explanation for the fragmentation pattern was proposed. The Z-scheme process confers improved charge separation and long-term photostability on the system, and provides new insights for the design of redox-mediator-free RGObased Z-scheme composites for photocatalysis applications. (C) 2017 Elsevier B.V. All rights reserved.