Energy band engineering of Bi_(2)O_(2.33)–CdS direct Z-scheme heterojunction for enhanced photocatalytic reduction of CO_(2)

摘要

In this work,a Bi_(2)O_(2.33)–CdS direct Z-scheme heterojunction was fabricated based on energy band engineering.The Bi_(2)O_(2.33)core nanoflakes were first synthesized by electrodeposition which was followed by an annealing process to fabricate this heterojunction.Then the Cd S shell was deposited on Bi_(2)O_(2.33)nanoflakes utilizing the solution method,during which a suitable concentration of Cd Clsolution was used for forming a homogeneous and continuous integrated CdS shell.A space charge region and an internal electric field from CdS(+)to Bi_(2)O_(2.33)(-),which drove a direct Z-scheme charge transfer process,were formed at the interface.The Bi_(2)O_(2.33)–CdS exhibited excellent photocatalytic performance for CO_(2)reduction mainly attributed to the satisfactory photoinduced charge separation and transport efficiency in the direct Z-scheme heterojunction.The photocatalytic CO_(2)reduction ability of Bi_(2)O_(2.33)–CdS was significantly enhanced compared with single Bi_(2)O_(2.33)or Cd S,with a CO_(2)yield rate of ca.2.9μmol/(cm^(2)h)under a 300 W Xe lamp.The reduction of CO_(2)to CO_(2)demonstrated 94.0%selectivity.