Bismuth vanadate (BiVO4) is an attractive, low-cost n-type semiconductor that exhibits excellent photoelectrocatalytic properties, chemical stability, and biocompatibility. This study reports a newly discovered function of BiVO4 dissociating highly stable, self-assembled amyloid aggregates associated with Alzheimer's disease. A visible light-active, nanoporous BiVO4 platform is developed to break -amyloid (A beta) assemblies and alleviate A aggregate-induced toxicity. Multiple photochemical and microscopic analyses reveal that beta-sheet-rich, long A beta fibrils are effectively destabilized and broken into small-sized, soluble species by BiVO4 photoelectrode under illumination of a white light-emitting diode and an anodic bias. The photoactivated BiVO4 under anodic bias generates oxidative stress, such as superoxide ions and hole-derived hydrogen peroxide, which causes photooxidation of A beta residues and irreversible disassembly of A beta aggregates. The efficacy of photoelectrocatalytic dissociation of A beta aggregates is enhanced by Mo-doped BiVO4, which facilitates the separation of electron-hole pairs by improving electron-transport properties of BiVO4. Furthermore, it is verified that both pristine and Mo-doped BiVO4 photoelectrodes are nontoxic and effective in reducing A beta-associated cytotoxicity. The work shows the potential of BiVO4-based photoelectrode platforms for the dissociation of neurotoxic, highly stable A beta assemblies using light energy.