[Display omitted] Heterogeneous catalysis composed of plasmonic metal and semiconductor has been utilized to tune local surface electron density in MOA (Molecular oxygen activation). However, there is a severe antagonistic effect between Schottky junction carriers and SPR (Surface Plasmon Resonance) induced hot carriers transfer routers when metal and semiconductor are both excited to dramatically reduce carriers separation efficiency. Hence, a highly effective photocatalytic antifoulant obtained by V-CN (carbon nitride with nitrogen vacancies) in-situ loading Cu 2 O and Ag nanoparticles (Cu 2 O/Ag/V-CN) was introduced to promote MOA to assist the metal ions sterilization. The DFT calculations (Density Functional Theory) and FEM calculations (Finite Element Method) intuitively proved the photocatalytic antifoulant belonged to a ternary Z-scheme heterojunction and could visibly weaken the antagonistic effect of hot carriers and Schottky carriers transport routes. The delocalized electron structure caused by V-CN and the effective electron mediator of Ag were the key to the formation of Z-scheme interfacial heterojunctions. These conclusions were also supported by experimental data, like more ∙O 2 – production capacity, efficient carriers separation, and higher carriers lifetime (27% higher than Cu 2 O and Cu 2 O/V-CN) as well as the weakened Cu 2 O photocorrosion tendency (Cu 2 O turning into CuO). Additionally, except for increasing nearly-three times adsorption energy of O 2 for rapid activation, Cu 2 O/Ag/V-CN with abundant nitrogen vacancies can more significantly slow metal ions release (less about 97% to pure Cu 2 O and at least 22% higher than reported systems), which can observably save the amount of catalyst and heavy metals content. Therefore, Cu 2 O/Ag/V-CN has great potential for practical antifouling applications. [ABSTRACT FROM AUTHOR]