  Submicron core/shell Ti/TiOx photocatalyst is successfully synthesized via
single-mode magnetic microwave (SMMW) assisted direct oxidation of planetary
ball-milled TiH2. The thickness of TiOx shell including highly concentrated
defects such as Ti3+ and/or oxygen vacancies is controllable in the range from
6 to over 18 nm by varying the treatment time in the SMMW assisted reaction. In
addition to its quite narrow optical bandgap (1.34-2.69 eV) and efficient
visible-light absorption capacity, the submicron Ti/TiOx particle exhibits
superior photocatalytic performance towards H2 production from water under both
UV and visible-light irradiation to compare with a commercial TiO2
photocatalyst (P-25). Such excellent performance can be achieved by the
synergetic effect of enhancement in visible light absorption capacity and
photo-excited carrier separation because of the highly concentrated surface
defects and the specific Ti/TiOx core/shell structure, respectively.
