Reductive Reconstruction Activates High‐Entropy Perovskite Fiber–ZnIn ₂ S ₄ Interfaces in Photocatalytic Hydrogen Evolution and Solar Water Evaporat

ABSTRACT

Solar‐driven hydrogen production offers a sustainable route for converting solar energy into chemical fuels, yet whether the nanoscale interfacial advantages achieved in particulate photocatalysts can be retained after macroscale membrane assembly remains a fundamental challenge. Herein, a hydrogen‐induced lattice reconstruction strategy is developed to regulate high‐entropy perovskite La _0.95 (Fe _0.2 Co _0.2 Ni _0.2 Cr _0.2 Ti _0.2 ) _1.05 O _3‐δ (LB5O ₃ ) nanofibers for integration with ZnIn ₂ S ₄ (ZIS). Controlled H ₂ reduction modifies near‐surface perovskite environments of the LB5O ₃ fibers, followed by in situ growth of ZIS nanosheets to form reconstruction‐derived oxide–semiconductor interfaces, yielding reconstructed heterojunctions with a particulate H ₂ evolution rate of 16 673 µmol·h ⁻¹ ·g ⁻¹ . To bridge the gap between particulate catalytic efficiency and functional device translation, these hybrid fibers were assembled into a supported floating membrane. When operated in the floating configuration, the membrane exhibits localized photothermal heating and continuous capillary water transport at the air–water interface, and achieves an H ₂ evolution rate of 17 875 µmol·h ⁻¹ ·g ⁻¹ . The fibrous architecture further achieves a dark‐corrected solar evaporation rate of 1.60 kg·m ⁻² ·h ⁻¹ with a solar‐to‐vapor conversion efficiency of 87.3%. Furthermore, outdoor field tests conducted under naturally fluctuating sunlight demonstrate consistent hydrogen production across five days of cycling tests alongside simultaneous freshwater production from simulated seawater.