Fabrication of In2O3/In2S3 microsphere heterostructures for efficient and stable photocatalytic nitrogen fixation

The synthesis of a novel In 2 O 3 /In 2 S 3 microsphere heterostructures is conducted through a well-designed two-step hydrothermal method. These composites are first applied for efficient fixation of N 2 to NH 3 under mild conditions without any organic scavengers and precious-metal cocatalysts. Here the In 2 S 3 flakes are in situ generated and uniformly assembled on In 2 O 3 microsphere. The phase structures, morphologies and oxygen vacancies of the samples are systematically characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse-reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL), Raman, electron spin resonance (ESR) spectroscopy and photoelectrochemistry. Meanwhile, the investigation of photocatalytic performance can confirm that the nitrogen fixation rate of In 2 O 3 /In 2 S 3 (III) heterostructure is 40.04 μmol g −1  h −1 , which is about 4.7 and 6.0 times higher than that of pure In 2 O 3 and In 2 S 3 , respectively.