Herein, a nitrogen-rich g-C3N5 @MoO3 hybrid material has been prepared via an ultrasonic method, and its photo- and electro-catalytic properties were confirmed through the degradation and determination of acetaminophen (AP) were reported. The as-prepared materials were confirmed using some analytical techniques including XRD, FT-IR, DRS, BET, XPS, SEM, TEM, EDX, and mapping analysis. In addition to that, the electron transfer properties as well as recombination were confirmed by photocurrent and impedance spectroscopy. The optimized g-C3N5 @MoO3 (10%) photocatalyst shows an excellent electron transfer and reduces the recombination rate of electron and hole pairs which was confirmed by the degradation of AP in the aqueous environment. The degradation rate and kinetic constant were calculated and presented. The radical scavengers test was investigated and proposed the degradation mechanism of g-C3N5 @MoO3 (10%) via Z-scheme. In addition, the g-C3N5 @MoO3 (10%) catalyst was fabricated on GCE and utilized for the detection of AP via electrochemically (CV, DPV, and impedance). The limit of detection and sensitivity of the prepared g-C3N5 @MoO3 were investigated thoroughly and presented. The electro-catalytic mechanism was also proposed and studied. These higher photo- and electro-catalytic properties of g-C3N5 @MoO3 (10%) are due to the higher surface area and synergistic effect between both g-C3N5 and MoO3. Hope this method and fabrication of materials could be an effective way to prepare new nanomaterials with high performance.