The effect of doping variation on band gap energy and crystal structure of Biochar/TiO2 thin layer

Abstract

The biochar/TiO2 thin layer has been made by using the sol-gel method and the coating technique by Doctor Blade method. The variation of biochar on TiO2 were 0%, 1%, 2%, 3% and 4%. The characterization was done by using XRD (X-Ray Diffractometer) to see the crystal structure of samples and UV-Vis spectrophotometer to obtain the value of band gap energy. Based on XRD data, it was obtained that the crystal structure of all samples is anatase TiO2. The crystalline size of all samples has no significant difference by the increasing of doping percentage. The smallest crystal size was at the addition of 3% and 4% bio char which was 118.22 nm. The results of UV-Vis characterization showed the lowest value of band gap energy was at sample doping 1% bio char which was 3.25 eV. Band gap energy value for doping sample above 1% showed an increase of band gap energy of Biochar-TiO2.