Synthesis of Fe₃O₄@CdS@CQDs ternary core-shell heterostructures as a magnetically recoverable photocatalyst for...

Photocatalytic aerobic oxidation of aromatic alcohols to corresponding aldehydes coupled with producing hydrogen peroxide (H₂O₂) represents one of the most efficient strategies for converting solar energy into chemical energy. In this work, a magnetically recoverable photocatalyst of Fe₃O₄@CdS@CQDs ternary core-shell heterostructures is elaborately fabricated through the hydrothermal growth of CdS on Fe₃O₄ nanospheres with in-situ incorporation of carbon quantum dots (CQDs) and used for selective alcohol oxidation coupled with H₂O₂ production. The Fe₃O₄@CdS@CQDs photocatalyst possess distinct advantages of full solar spectral absorption, efficient charge separation, and high stability. The Fe₃O₄-nanosphere cores not only endow photocatalyst with the characteristics of magnetic recovery but also form Fe₃O₄@CdS Z-scheme heterojunction to prevent CdS from photocorrosion. The in-situ modified CQDs act as charge mediators to accelerate the photogenerated electron-hole separation and afford active sites to facilitate H₂O₂ production. As a result, the Fe₃O₄@CdS@CQDs photocatalyst exhibits excellent performance in selectively converting benzyl alcohol to benzaldehyde accompanied with H₂O₂ production. The generation rates of benzaldehyde and H₂O₂ reach up to 57.22 and 27.06 mmol·g_CdS^-1·h^-1, respectively. This work highlights a rational construction of magnetic heterostructure photocatalyst and its application in the photo-redox coupling reactions.