Photothermal synergy of 1D Cd0.9Zn0.1S and 3D Mn3O4 for achieving forcefully active and highly selective aromatic alcohol oxidation

Abstract

Constructing photothermal catalysts is a promising strategy to improve the efficiency of selective photocatalytic oxidation of aromatic alcohol to aromatic aldehyde. Herein, Mn3O4/Cd0.9Zn0.1S (CZS) photothermal catalysts have been prepared by introducing an as-prepared CZS photocatalyst during Mn3O4 preparation. The Mn3O4/CZS samples exhibit higher catalytic performance for selective oxidation (SO) of aromatic alcohol. Especially, the optimized 10% Mn3O4/CZS sample possesses 7 times yield of CZS with an over 90% selectivity. The photothermal synergetic catalytic mechanism of Mn3O4/CZS for the SO of aromatic alcohol was proposed. Mn3O4 (2MnO•MnO2) severs as the center of thermal catalysis and O2 adsorption. The high-valent MnO2 oxidized aromatic alcohols into aromatic aldehydes and the generated low-valent MnO was oxidized to MnO2 by adsorbed O2, forming a thermal cycling reaction. Meanwhile, the photoexcited electrons (e–) originating from CZS were transferred to Mn3O4 due to the matching energy level of MnO and CZS and further reduced the adsorbed O2 to active oxygen (•O2–) and lattice oxygen (O2–), availably accelerating the separation of photoexcited carriers. Finally, •O2–, O2– and photoexcited holes (h+) can also selectively oxidize aromatic alcohol. This study provides an alternative paradigm for the efficient SO of aromatic alcohol.