Mixed-dimensional van der Waals heterojunctions have attracted a great deal of attention due to their excellent photoelectric conversion capability, which have been widely applied for self-powered photoelectrochemical (PEC)-type devices as the growing demands of clean energy, environmental governance and protection, and the underwater communications. In this work, 0D Bismuth quantum dots (Bi QDs) encapsulated 2D g-C3N4 nanosheets (g-C3N4@Bi) mixed-dimensional heterojunctions were prepared and spined on ITO-coated polyethylene terephthalate (PET...