Display omitted •1-D Cu(tba)2(H2O)⋅2H2O (abbreviated as 1D-Cu, tba = 3-1,2,4triazol-1-yl-benzoic acid) complex nanoparticles were synthesized using the hydrothermal method.•Photocatalytic degradation of methylene blue and indole-3-acetic acid by 1D-Cu nanoparticles were studied.•Synergetic effect of 1D-Cu complex and H2O2 was found in the photocatalytic process.•Kinetic behavior and possible mechanism of photocatalytic processes were investigated. One-dimensional complex Cu(tba)2(H2O)⋅2H2O (abbreviated as 1D-Cu, tba = 3-1,2,4triazol-1-yl-benzoic acid) micropowders were synthesized using the hydrothermal method, and further characterized by powder X-ray diffraction, elemental analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy and UV–vis diffuse reflectance spectra. The photodegradation of methylene blue (MB) and indole-3-acetic acid (IAA) were studied under UV irradiation using 1D-Cu as catalysts in the presence of H2O2. The degradation efficiency of MB was up to 84.9 % after irradiating for 90 min under UV light, while the degradation efficiency of IAA was over 60.4 % after irradiating for 4 h. Reaction kinetics studies showed that both MB and IAA were in accordance with the pseudo-first-order reaction kinetics in the photodegradation process, and the t1/2 for MB and IAA was 31.2 and 183.4 min, respectively. FT-IR and powder X-ray diffraction tests suggested that 1D-Cu catalyst exhibited excellent stability toward the photocatalytic reactions. Besides, the mechanism of photocatalytic reaction catalyzed by 1D-Cu was discussed, and the synergistic effect of 1D-Cu and H2O2 was also studied. This study provides a 1D-Cu/H2O2 catalytic system for the photocatalytic degradation of harmful organic dyes and phytohormones in water.