Constructing the novel ultrafine amorphous iron oxyhydroxide/g-CN nanosheets heterojunctions for highly improved photocatalytic performance.

Ultrafine particles, more heterojunction interfaces and amorphous materials can effectively enhance the photocatalytic activity of photocatalysts. In this work, a facile in-situ precipitation method was developed to prepare ultrafine amorphous iron oxyhydroxide/ultrathin g-CN nanosheets heterojunction composites. The amorphous iron oxyhydroxide possessed an ultrafine particle size and a wide range of visible light absorption. In this process, the ultrafine particles not only shortened the diffusion distance of photogenerated carriers, but also facilitated the formation of more heterojunctions with ultrathin g-CN nanosheets. The photocatalytic activities were evaluated using rhodamine B, methylene blue, and methyl orange as pollution models under visible light irradiation. Notably, the optimal photocatalytic activity of a-FeOOH/CNNS-800 composite is ~17.8 times higher than that of CNNS towards the degradation of rhodamine B under visible light. The outstanding photocatalytic activities were ascribed to the narrower band gap, the enhanced visible light absorbance, abundant heterojunction interfaces, and the effective separation of the photogenerated charges driven by the matched band edge in the heterostructures. We trusted that the facile and easy-to-extend synthesis method can be further expanded to synthesize other ultrafine semiconductors coupled with g-CN for enhancing the photocatalytic activities.