Holmium silicate nanostructures: Simple auto-combustion preparation, characterization, and scrutiny of photocatalytic performance

Though industrial progress has improved mankind's standard of living, it has also degraded the environment. The lack of freshwater in the cosmos has led researchers to pay close attention to water contamination. The holmium silicate nanostructures with Ho₂Si₆O₉ formula were prepared through a multifuel auto-combustion process involving starch, fructose, and maltose. Obtaining Ho₂Si₆O₉ in the presence of starch results in a pure and morphologically desirable sample. Considering the suitable bandgap (3.01 eV) of Ho₂Si₆O₉, this compound could be a good candidate for the degradation of toxic organic compounds in the UV range. Several factors play a crucial role in the purification of water, such as the type of organic contamination, the content of catalysts, and the concentration of pollutants. Results showed that 50 mg of Ho₂Si₆O₉ decomposed 5 ppm thymol blue in a high percentage (91.4%). The scavenger test revealed that superoxide (•O₂⁻) species played a significant role in photodegradation. The kinetics study confirmed that the maximum efficiency has a maximum rate constant (k = 0.0191 min⁻¹).