Display omitted •Novel rGO/ZrO2/Ag3PO4 composite was synthesized via a green hydrothermal approach.•Contaminant degradation by adsorption–photocatalysis synergy was confirmed.•Optimal band-edge alignment of ZrO2/Ag3PO4 provided high photocatalytic performance.•Structural stability and reusability of the composite favor practical applications.•The quantum yield of this system exceeds previously reported values. Synergy between surface adsorption and photocatalysis is key for effective contaminant degradation in the liquid phase. Herein, we report a heterojunction photocatalyst of reduced graphene oxide (rGO)/zirconium dioxide (ZrO2)/silver phosphate (Ag3PO4) that incorporates this synergy for 4-nitrophenol (PNP) removal. Compared with other photocatalyst combinations, ZrO2 and Ag3PO4 coupling generates reactive species with greater degradation potential. ZrO2 and rGO were synthesized by a green approach using a one-step hydrothermal reaction in ethanol–water. The growth of rGO/ZrO2 and Ag3PO4 were accomplished and the functions of each part were well developed together. The rGO/ZrO2/Ag3PO4 composite exhibited enhanced light absorption and a low band gap energy (2.3 eV) owing to rGO and Ag3PO4 integration. The composite’s photocatalytic activity was much higher than that of ZrO2, Ag3PO4, or ZrO2/Ag3PO4. The maximal adsorption of PNP was 26.88 mg/g, and a pseudo-first-order model described the PNP degradation kinetics (k = 0.034 min−1). Synergy between the three components resulted in 97% PNP removal in 90 min, and even after five cycles, 94% PNP removal was obtained. The quantum yield of the system (7.31 × 10−5 molecules/photon) was compared with those in previous reports to assess the photocatalytic performance and energy requirements.