Interfacial electric fields are widely exploited in heterojunction photocatalysts to promote charge separation. However, conventional type-II heterojunctions inevitably suffer from severe loss of redox potential, while Z-/S-scheme architectures retain strong redox capability only at the expense of substantial carrier consumption. Here, we propose a polarization-driven $\Upsilon$-scheme heterojunction that harnesses two oppositely oriented polarization fields to establish an unconventional charge-transfer pathway. Specifically, polarized Janus monolayers ($\mathrm{M}\text{−}{\mathrm{M}}^{\prime }\text{−}\mathrm{C}\text{−}\mathrm{X}\text{−}{\mathrm{X}}^{\prime }$; $\mathrm{M}/{\mathrm{M}}^{\prime }=\mathrm{Sc}$, Y; $\mathrm{X}/{\mathrm{X}}^{\prime }=\mathrm{F}$, Cl, Br, H) are integrated with ferroelectric MXenes (${\mathrm{M}}_2{\mathrm{CO}}_2$; M $=$ Sc, Y), enabling intralayer electron migration toward high-potential regions and hole migration toward low-potential regions. This mechanism preserves intrinsic redox potentials while suppressing interfacial recombination, thereby facilitating near-complete utilization of photogenerated carriers. Consequently, oxidation and reduction reactions are spatially separated at the surface and interface, respectively. Our strategy resolves the long-standing dilemma between maintaining strong redox potentials and maximizing carrier utilization, offering a robust design principle for next-generation high-efficiency photocatalysts.

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• Electric polarization
• Ferroelectricity
• Photocatalysis
• Janus materials
• Junctions
• MXenes
• Monolayer films
• Density functional calculations