Tuning the Anisotropic Facet of Lead Chromate Photocatalysts to Promote Spatial Charge Separation
Wenchao Jiang, Chenwei Ni, Lingcong Zhang, Ming Shi, Jiangshan Qu, Hongpeng Zhou, Chengbo Zhang, Ruotian Chen, Xiuli Wang, Can Li, Rengui Li
Abstract
Abstract A crucial issue in artificial photosynthesis is how to modulate the behaviors of photogenerated charges of semiconductor photocatalysts. Here, using lead chromate (PbCrO 4 ) as an example, we conducted the morphology tailoring from parallelepiped (p‐PbCrO 4 ) to truncated decahedron (t‐PbCrO 4 ) and elongated rhombic (r‐PbCrO 4 ), resulting in exposed anisotropic facets. The spatial separation of photogenerated charges closely correlates to the anisotropic facets of crystals, which can only be realized for t‐PbCrO 4 and r‐PbCrO 4 . The charge‐separation efficiencies exhibit a quasilinear relation with the surface photovoltage difference between anisotropic facets. The r‐PbCrO 4 gives an apparent quantum efficiency of 6.5 % at 500 nm for photocatalytic water oxidation using Fe 3+ ions as electron acceptors. Moreover, the oxidation reverse reaction from Fe 2+ to Fe 3+ ions was completely blocked with ∼100 % of Fe 3+ conversion achieved on the anisotropic PbCrO 4 crystals.