<p>Ammonium polyvanadate (APV) precipitation wastewater, which contains V and Cr ions, is a hazard waste that poses significant resource utilization challenges. The V and Cr single-atom-doped carbon-based catalysts have high potential for application in photoelectrocatalysis. This paper describes a method for the synthesis of V/CrNC catalysts using vanadium-containing industrial wastewater. The DFT calculations show that V/CrNC can spontaneously generate spin-polarized electrons in alkaline aqueous solution, which directly binds to oxygen-containing intermediates and obtains excellent activity and conductivity. The V/CrNC catalysts with uniform distribution of metal atoms were prepared in one step using vanadium precipitation wastewater and chitosan pyrolysis, and ORR test results with E_onset = 0.84 V and E_1/2 = 0.69 V were obtained, which are close to commercial Pt/C catalysts. This work broadens our horizons in resource recovery disposal, and it offers a theoretical framework and practical experience for the design and synthesis of economical catalysts.</p> Graphical Abstract <p></p>