Effects of annealing conditions and nanostructures on photocatalytic and degradation properties of In${}_2$O${}_3$

Indium oxide (In${}_2$O${}_3$) is widely accepted as a photocatalyst for its unique optical and electrical properties, as well as its favorable chemical stability. This study investigated the impact of annealing conditions and morphology on photocatalytic properties, by preparing four different nanostructures of In${}_2$O${}_3$ using glancing angle deposition based on electron beam evaporation. The results indicated that In${}_2$O${}_3$ annealed at 500 °C for 4 h exhibited optimal crystallization quality and photocatalytic performance. Given the fabricated structures, the slant nanorods structure of In${}_2$O${}_3$ demonstrated superior photocatalytic performance, achieving a photocurrent density of 0.34 mA/cm${}^2$, which was 2.1 times higher than that of the nanofilms (0.16 mA/cm${}^2$). Furthermore, this particular structure showed enhanced photodegradation efficiency for Rhodamine B with a degradation rate of 45.69%, suggesting an improvement of about 27% compared to nanofilms. The analysis of Nyquist plots revealed that the slant nanorod structure facilitated enhanced charge transfer capability, thereby significantly improved the photoelectrochemical properties.