Smart Charge Buffer-Modulated Multitime Scale Chemistry for Photocatalysis

Photocatalysis offers a compelling platform for green chemical synthesis driven by solar energy. However, a fundamental bottleneck arises from the temporal mismatch between ultrafast exciton-carrier kinetics and comparatively sluggish surface reaction dynamics, ranging from picoseconds to seconds, which significantly limits the overall efficiency. Here, we address this longstanding bottleneck by introducing a self-modulating "time scale coordination" strategy, which integrates ferrocene carboxaldehyde (FcCHO) molecules as a smart charge buffer onto energy-level-matched photocatalysts. Combining in situ femtosecond transient absorption spectroscopy and DRIFTS, we uncover that the FcCHO enables multitime scale interfacial chemistry through reversible switching between electron-accepting and electron-donating states across disparate time scales: rapid electron capture from photoexcited photocatalysts occurs within picoseconds, while controlled electron release to drive interfacial CO2 reduction is kinetically delayed to the second time scale. This dual-time scale, self-regulated charge buffering behavior enables rapid charge sequestration and demand-driven charge release, which weakens the exciton binding energy by 39.0% and markedly suppresses electron-hole recombination by 62.8%. Importantly, this time scale coordination strategy is generalizable and can be extended to diverse photocatalytic systems, establishing a universal design principle for synchronizing fast charge dynamics with slow interfacial reaction kinetics for green carbon conversion.