Nitrate (NO3-) pollution in surface and groundwater, worsened by nitrogen-rich fertilizers in agriculture, poses a significant challenge. Conventional methods remove NO3- physically, yielding concentrated reject water needing further treatment. Electrochemical processes use electrons to convert NO3- into ammonia (NH3) or dinitrogen (N2). This project explores photoelectrocatalysis, enhancing selectivity for NH3 as an added-value product using a photocathode based on tri-layers. Titanium oxide (TiO2) nanorods modified with Ag and CuOx nanoparticles that exhibit high NO3- conversion rates and exceptional NH3 selectivity. Mechanism evaluation reveals additive effects between photocatalysis and electrocatalysis, surpassing individual performances. This approach offers promising solution for NO3- pollution remediation and sustainable resource recovery in agriculture.