Efficient solar-driven hydrogen production requires photoanodes that combine strong light absorption with effective catalytic activity. Here, we report a FeVO4/FeCoS2 (FVO/FCS) heterostructure photoanode, fabricated by hydrothermally growing FVO nanopebbles on FTO, followed by in-situ transformation of FeOOH and deposition of FCS nanoparticles to form a well-coupled interface. The FVO/FCS photoanode achieved a zero-bias photocurrent density of 0.59 mA cm(-2) under AM 1.5 G illumination, which is similar to 4.5 times higher than pristine FVO, demonstrating the synergistic effect of type-II band alignment and catalytic surface activity. Mott-Schottky and electrochemical impedance analyses confirmed enhanced charge separation, increased donor density, and reduced interfacial resistance. This work establishes the first demonstration of FCS integration onto FVO to simultaneously promote carrier separation and surface catalysis. The study addresses a critical challenge in designing efficient heterojunction photoanodes and provides a sustainable route for PEC water splitting. These findings have broader implications for developing environmentally friendly solar hydrogen generation technologies, highlighting the potential for scalable, high-performance photoelectrodes with rational interface engineering.