Boosting the Photocarrier Separation of PbMoO₄ through Facet Collaboration

Abstract

Boosting photocarrier separation efficiency is a critical step for the catalyst itself or composites based on such catalysts. The use of the reaction raw material to accomplish crystal facet control and ratio optimization is an important and challenging subject in the field of facet engineering, as the activity of the photocatalyst can be improved without introducing impurities. Here, we report the evolution of PbMoO 4 from a lamellar to a 26-faceted polyhedron via a wet chemical method. The redox crystal facet ratio does not change the light absorption capacity, but the photocarrier separation efficiency is improved depending on the ratio of oxidized (111)/reduced (001) surfaces. Based on the exposed facet band structure, electrostatic potential, and EDX of photodeposited species, adjacent (101) only contributes to the transport and separation of photogenerated electrons (e − ) from ( 111) to (001), while photogenerated holes (h + ) respectively migrate from ( 101) and ( 001) to ( 111) under the different valence band position and electrostatic potential. The collaboration of three crystal planes with a certain ratio maximizes the separation of carriers and produces dramatic changes, such as from the inability of H 2 O oxidation to the ability of O 2 evolution (18.78 μmol/(g•h)). In addition, there are more effective h + that can simultaneously participate in the oxidation of other substances during the production of reactive oxygen species (ROS). So, a larger ratio of (111)/(001) combined with a harmonized (101) crystal surface makes a PbMoO 4 polyhedron that has more excellent photocarrier separation ability and versatile oxidation capacity.

An efficient hydrogen evolution photocatalyst of Rh@Cr2O3-loaded PbMoO4 twenty-six facet polyhedrons

“…Inspired by a Cu 2 O-truncated octahedron synthesized by controlling pH, [36][37][38] we studied the raw material ratio and pH adjustment and obtained a PbMoO 4 twenty-six facet polyhedron. 39 However, no HER was observed in our preliminary study, suggesting an insufficient HER overpotential or lack of active sites. Therefore, this needs to be improved.…”

“…The XRD pattern of PM is well indexed to tetragonal PbMoO 4 (JCPDS: 44-1486). 39 For PM/Pt, PM/Rh and PM/Rh@Cr 2 O 3 , no characteristic peak of Pt, Rh and Cr 2 O 3 could be observed, suggesting the content of the co-catalyst to be below the detection limit of XRD. The Raman spectrum also shows that PM is tetragonal PbMoO The morphology of PM/Rh@Cr 2 O 3 was investigated by SEM.…”