The article discusses the development of a novel gallium-nitride (GaN) semiconductor in the form of a nanowire array grown on a silicon substrate for efficient photoelectrochemical (PEC) water splitting to generate hydrogen. By tailoring the GaN nanowires through a selective chemical-etching step and loading them with Au nanoparticles as cocatalysts, the constructed Au/Faceted-GaN/Si photocathodes demonstrate high performance with an onset potential of 0.52 V vs. RHE and a large applied bias photon-to-current efficiency of 10.36% under solar illumination. The study showcases a one-dimension on three-dimension (1D/3D) configured photoelectrode architecture that achieves both high efficiency and stability in PEC hydrogen evolution for over 800 hours. The innovative approach involves facet-induced strong electronic interactions at the GaN/Au interface, forming a reconfigured GaN nanowire/Au heterointerface that enhances stability and catalytic activity. This strategy provides a promising platform for future advanced hydrogen production. The research represents a significant step towards sustainable hydrogen fuel generation through a renewable and environmentally friendly process.