Ag2 S-CdS p-n Nanojunction-Enhanced Photocatalytic Oxidation of Alcohols to Aldehydes.

Selective oxidation of alcohols to aldehydes under mild conditions is important for the synthesis of high-value-added organic intermediates but still very challenging. For most of the thermal and photocatalytic systems, noble metal catalysts or harsh reaction conditions are required. Herein, the synthesis and use of Ag2 S-CdS p-n nanojunctions as an efficient photocatalyst for selective oxidation of a series of aromatic alcohols to their corresponding aldehydes is reported. High quantum efficiencies (59.6% and 36.9% under 380 and 420 nm, respectively) are achieved in air atmosphere at room temperature. Photoluminescence and photo-electrochemical tests show that the excellent performance is mainly due to the p-n junction-enhanced charge separation and transfer for the activation of both O2 (in air) and substrates. This study demonstrates the potential of p-n junction in photocatalytic synthesis under mild conditions.