Photocatalyzed　CO2　reduction　(CO2RR)　transfers　CO2　into　valuable　products　using　renewable　energy,　attracting　widespread　attention.　Composite　catalysts　fabricated　with　TiO2　and　red　phosphorus　(RP)　might　exhibit　competitive　advantages,　but　effective　interphase　binding　is　difficult　to　forge.　The　composites　therefore　require　complex　and　energy-consuming　syntheses,　severely　hindering　their　application　in　CO2RR.　In　this　work,　TiO2/RP　composites　with　hyperefficient　interphase　contact,　which　outperform　various　elaborately　designed　catalysts,　are　directly　prepared　from　commercially　available　materials　via　a　green　and　facile　hydrothermal　approach.　The　low　heating　temperature　and　sole　solvent　of　water　diminish　the　energy　input　for　synthesis　and　imply　a　potential　opportunity　to　propel　CO2RR　with　industrial　waste　heat　and　cooling　water.　Experimental　and　computational　analyses　reveal　that　hydrothermal　synthesis　reduces　the　interfering　oxidized　species　on　the　exterior　surface　of　RP,　facilitating　the　relatively　less　favored　interphase　contact　between　TiO2　and　nonoxidized　RP.　Photoelectron　transfer　and　catalytic　performance　of　the　composites　are　hence　drastically　enhanced.　Further　improvement　of　activity　is　feasible　by　slightly　elevating　the　heating　temperature,　time,　or　solution　acidity.　Attributing　to　the　universal　applicability　of　this　green　approach,　different　metal　oxide/RP　composites　(e.g.,　WO3/RP)　are　similarly　prepared,　consistently　boosting　the　reaction　rate　multiple　times.