In　heterogeneous　photocatalysis,　the　dynamics　of　charge　carriers　holds　particular　significance　for　comprehending　the　underlying　catalytic　mechanism　and　designing　highly　efficient　photocatalysts.　The　current　technological　challenge　lies　in　how　to　maximize　the　behavior　of　carriers　and　enable　them　to　unleash　their　potential　in　photocatalytic　reactions.　Herein,　we　present　a　novel　Prussian　blue　analogue　(PBA)-derived　InFe-based　oxide　(denoted　as　InFe-x),　which　features　internal　Fe　doping　and　an　external　crystalline/amorphous　heterojunction,　serving　as　an　effective　photocatalyst　for　photocatalytic　reverse　water　gas　shift　(RWGS)　reactions.　Experiments　and　theoretical　simulations　have　confirmed　that　doping　Fe　into　In2O3　can　alter　the　electronic　and　energy　structure　and　achieve　the　spin　polarization　effect,　thereby　enhancing　the　intrinsic　carrier　generation　and　separation　behavior;　meanwhile,　the　formed　Fe-In2O3/Fe2O3　S-scheme　heterojunction　establishes　an　internal　built-in　electric　field　and　creates　a　new　transport　pathway　for　photogenerated　carriers,　which　significantly　inhibit　the　inherent　photogenerated　electron-hole　recombination.　Therefore,　this　＇internal　and　external　cultivation＇　strategy　can　fundamentally　optimize　and　maximize　the　behavior　of　charge　carriers,　thereby　significantly　enhancing　the　photocatalytic　CO2　hydrogenation　performance.　©　2025　The　Royal　Society　of　Chemistry.