Synthesis of a novel Type-II In2S3/Bi2MoO6 heterojunction photocatalyst: Excellent photocatalytic performance and degradation mechanism for Rhodamine B

Abstract Indium sulfide (In2S3) has been proven to be a photocatalyst with giant potential, but its photocatalytic activity is still severely limited by the disadvantages such as the sluggish charge separation. Herein, a series of novel photocatalysts with Type-II In2S3/bismuth molybdate (Bi2MoO6) heterostructures were handily fabricated through hydrothermal route. Under 90 minutes of visible light illumination, all the In2S3/Bi2MoO6 heterostructures demonstrated more splendid activity for Rhodamine B (RhB) degradation than pure In2S3 and Bi2MoO6 at low catalyst dose (0.2 g/L). Especially, the IB-2 displayed the highest degradation efficiency (88.2 %) and the fastest degradation velocity (k=0.02826 min-1), where its k value was nearly 2.48 and 6.51 times stronger than that of In2S3 and Bi2MoO6, respectively. More importantly, the removal efficiency was still above 81.4 % after 4 cycles. The reinforced photocatalytic activity was ascribed to the increase of active sites, extending of visible light response and forceful transfer of carriers. Meanwhile, the Type-II charge transfer mechanism was evidenced by the result of radical trapping test. As a complement, this work offers new insights for establishing efficient and stable In2S3-based composite photocatalysts.