Fig. 3: Optical properties and electrochemical performance of prepared samples.

a UV-Vis diffuse reflectance spectra of Cu₂O MCs, Cu₂O RMCs, Cu₂O TMCs, g-C₃N₄ NSs, Cu₂O/g-C₃N₄-0.1–0.5 MPHs. b PL spectra, (c) i–t curves and (d) EIS Nyquist plots of Cu₂O MCs, g-C₃N₄ NSs, and Cu₂O/g-C₃N₄-0.2 MPH