δ-MnO2-Mn3O4Nanocomposite for Photochemical Water Oxidation: Active Structure Stabilized in the Interface.
Pure phase manganese oxides have been widely studied as water oxidation catalysts, but further improvement of their activities is much challenging. Herein, we report an effective method to improve the water oxidation activity by fabricating a nanocomposite of Mn3O4and δ-MnO2with an active interface. The nanocomposite was achieved by a partial reduction approach which induced an in situ growth of Mn3O4nanoparticles from the surface of δ-MnO2nanosheets. The optimum composition was determined to be 38% Mn3O4and 62% δ-MnO2as confirmed by X-ray photoelectron spectra (XPS) and X-ray absorption spectra (XAS). The δ-MnO2-Mn3O4nanocomposite is a highly active water oxidation catalyst with a turnover frequency (TOF) of 0.93 s-1, which is much higher than the individual components of δ-MnO2and Mn3O4. We consider that the enhanced water oxidation activity could be explained by the active interface between two components. At the phase interface, weak Mn-O bonds are introduced by lattice disorder in the transition of hausmannite phase to birnessite phase, which provides active sites for water oxidation catalysis. Our study illustrates a new view to improve water oxidation activity of manganese oxides.
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China.
Zhibin
Z
Geng
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China.
Yanxiang
Y
Wang
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China.|Inner Mongolia Key Lab of Chemistry of Natural Products and Synthesis of Functional Molecules, College of Chemistry and Chemical Engineering, Inner Mongolia University for the Nationalities (IMUN) , Tongliao 028000, People's Republic of China.
Jinghai
J
Liu
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China.
Guangshe
G
Li
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China.
Liping
L
Li
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China.
Keke
K
Huang
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China.
Long
L
Yuan
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University , Changchun 130012, People's Republic of China.
Shouhua
S
Feng
active interface; manganese oxides; nanocomposite; water oxidation; weak Mn−O bond