Search

Low-temperature synthesis of YBaCo4O7+δ leads to the formation of nanosized particles and stacking faults with specific oxygen storage properties.

The oxygen intake/release characteristics were systematically studied for Ca2AlMnO5+δ samples synthesized under precisely controlled oxygen pressures. Both the oxygen storage capacity (OSC) and operating temperature were systematically lowered as the oxygen pressure in the firing atmosphere increased. Notably, the sample fired under a 1% O2 atmosphere exhibited sufficiently large OSC and superior oxygen intake/release kinetics to the pristine sample synthesized in an anaerobic condition. The high-angle annular dark-field scanning TEM observation revealed that the samples contain defects in their atomic arrangement when fired in oxygen-rich atmospheres. This result indicates that the oxygen intake/release characteristics of Ca2AlMnO5+δ are sensitive to the synthesis condition and widely tunable even without chemical substitutions.

The oxygen intake/release characteristics were systematically studied for Ca

A visible light sensitive ultrathin nanosheet Sn3O4 was synthesized by hydrothermal reaction using structure directing agent such as polyvinylpyrrolidone (PVP). Nanosheet Sn3O4 with 2 nm thick, corresponding to two-fold Sn-O-Sn sheet stacked layer, significantly catalyzed hydrogen evolution from aqueous methanol solution under irradiation of visible light (λ > 400 nm), even without co-catalyst loading. The hydrogen evolution of the nanosheet Sn3O4 was much superior to bulk Sn3O4 and representative hydrogen evolution photocatalysts such as CdS and g-C3N4. The apparent quantum yield was 0.3 % competitive to that of co-catalyst loaded doped photocatalyst. The enhanced hydrogen evolution is attributed to the synergistic effect of structural advantage of nanosheet and negative CBM position appropriate for hydrogen evolution in visible light. The nanosheet Sn3O4 will prompt the further exploration for simple semiconductor photocatalyst composed of abundant, cheap, and environmentally benign metal oxides for hydrogen evolution from water.