A promising biochar/ZnFe2O4 (BZF) composite has been synthesized to improve the efficiency of visible-light-driven H-2 evolution via a simple microwave hydrothermal method. The materials were investigated through diverse characterization means including XRD, FTIR, SEM, BET, XPS, VSM, UV-vis/DRS, PL, EIS. Different ratios of BZF composites expressed enhanced photocatalytic H-2 evolution performance over pure ZnFe2O4. Especially, biochar/ZnFe2O4 catalysts with 5:1 mass ratio (BZF-5) attained the optimal H-2 evolution rate, which is around 6 times higher than that of pure ZnFe2O4. Biochar acts as an electron mediator can effectively promote the separation of electron-hole pairs to enhance the rate of photocatalytic hydrogen evolution. Moreover, Eosin Y, photocatalyst and TEOA have synergistic effects accounted for enhanced photocatalytic performance in reaction system. Three cyclic runs for the photocatalytic H-2 evolution on BZF-5 sample illustrated its good stability and sustainable reusability. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.