Improved photocatalytic activities in highly ordered porous photocatalysts are often attributed to the larger surface area, higher light absorption, and suppressed charge recombination. Other underlying reasons for the improved charge transport, however, remain elusive at this stage. Herein, 3DOM BiVO₄ photocatalysts are examined to understand the carrier dynamics and their effects in photocatalytic water splitting. Quantum confinement arising from the ultrathin and crystalline wall upshifted its conduction band, enabling photocatalytic proton reduction to hydrogen gas under visible-light illumination. Time-resolved microwave conductivity spectroscopy reveals its ∼6 times higher charge mobility and longer charge diffusion length relative to the bulk counterpart. The long lifetime (∼360 ns) of 3DOM BiVO₄ with a power-law decay suggests the improved charge separation and the formation of shallow trapping states. Further investigation by Kelvin probe force microscope discloses a built-in electric field with upward band bending from the internal wall to the interconnection part of 3DOM BiVO₄.

中文翻译：

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揭示用于增强太阳能水分解的周期性多孔 BiVO4 光催化剂中的载流子动力学

高度有序的多孔光催化剂中改进的光催化活性通常归因于更大的表面积、更高的光吸收和抑制的电荷复合。然而，在现阶段，改进电荷传输的其他根本原因仍然难以捉摸。在此，研究了 3DOM BiVO ₄光催化剂以了解载流子动力学及其在光催化水分解中的影响。超薄晶体壁产生的量子限制使其导带上移，使光催化质子在可见光照射下还原为氢气。时间分辨微波电导率光谱显示其电荷迁移率比体相高约 6 倍，电荷扩散长度更长。3DOM BiVO 的长寿命（~360 ns）₄与幂律衰减表明改进的电荷分离和浅俘获态的形成。开尔文探针力显微镜的进一步研究揭示了一个内置电场，从内壁到 3DOM BiVO ₄的互连部分具有向上的带弯曲。