TiO2 was important semiconductor oxide photocatalytic material, which was widely applied in photocatalytic water splitting, organic compound conversion, CO2 conversion, etc. Various TiO2 nanostructures, TiO2 hetero-materials were developed. While heterogeneous photocatalyst generally suffer from low efficiency and sluggish photocarrier reaction kinetics, induced by electrons and holes self-recombination, defects quenching. Structure engineering, good crystallinity, loading with electron and hole reservoir were important for reduce the photocarrier's recombination and elevate photocatalytic performance. We fabricate Ag@TiO2 by one-step solvothermal synthesis in glycerol solvent, with AgNO3 and Titanium alkyloxide ester as reactants, which avoid complicated multi-step synthesis and coating procedures. AgNO3 were reduced by glycerol to form Ag nanorods, which yield trace amount of H2O, then Titanium alkoxide were hydrolysis to form atomic thin TiO2 coating layer. When trace amount of H2O was introduced into glycerol before the solvothermal reaction, more Titanium alkoxide were hydrolysis, thicker TiO2 nanoparticle layer were formed on the surface of Ag nanorods. The resultant Ag@TiO2 display good electron-hole separation effect, when irradiated under UV light, pristine white-colored composite would change to black within a minute. When stop from irradiation, the color fully recovered in a few seconds. The thin TiO2 coating layer reduced photocarriers' possible quenching or accumulation in the bulk TiO2, Ag rod modulate the electron transport direction, which elevate the photocarrier separation performance. This indicate that the composite materials could be used as efficient photochromism materials with good stability. And the Ag@TiO2 can prohibit electro-hole recombination effect, which could elevate the photocatalytic performance. Furthermore, this synthesis procedure could be applied in fabricate other materials with atomic thin coating photocatalyst layers.

Synthesis of Ag@TiO2 composite with atomic-thin TiO2 layer for photo chromism and photocatalysis

ACS Fall 2021

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