Reduced graphene oxide-mediated Z-scheme BiVO4/CdS nanocomposites for boosted photocatalytic decomposition of harmful organic pollutants
2018
Clament Sagaya Selvam, N. | Kim, Yeong Gyeong | Kim, Dong-Jin | Hong, Won-Hwa | Kim, Woong | Park, Sung Hyuk | Jo, Wan-Kuen
The efficient photocatalytic degradation of harmful organic pollutants (isoniazid (ISN) and 1,4-dioxane (DX)) via the Z-scheme electron transfer mechanism was accomplished using a photostable composite photocatalyst consisting of BiVO₄, CdS, and reduced graphene oxide (RGO). Compared to their pristine counterparts, the RGO-mediated Z-scheme CdS/BiVO₄ (CdS/RGO-BiVO₄) nanocomposites exhibited superior degradation activities, mainly attributed to the prolonged charge separation. RGO was found to be involved in visible-light harvesting and acted as a solid-state electron mediator at the CdS/BiVO₄ interface to realize an effective Z-scheme electron transfer pathway, avoid photocatalyst self-oxidation, and lengthen the life span of charge carriers. The results of reactive species scavenging experiments, photoluminescence measurements, and transient photocurrent measurements, as well as the calculated band potentials of the synthesized photocatalysts, supported the Z-scheme electron/hole pair separation mechanism. Additionally, the intermediates formed during the degradation of ISN and DX were identified, and a possible fragmentation pattern was proposed. This systematic work aims to develop photostable Z-scheme composites as unique photocatalytic systems for the efficient removal of harmful organic pollutants.
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