p-n异质结ZnO/HRP催化剂的制备及其光催化性能研究

Preparation of p-n heterojunction ZnO/HRP catalyst and study on its photocatalytic properties

p型半导体红磷(HRP)和n型半导体ZnO复合后形成p-n型异质结复合半导体催化剂ZnO/HRP。以Cr(Ⅵ)为模型污染物,研究了ZnO质量分数对催化剂光催化还原性能的影响。结果发现,ZnO/HRP复合光催化剂的光催化还原速率随ZnO质量分数的增加而增大,当ZnO的质量分数为0.25%时,ZnO/HRP复合光催化剂展现出最强的光还原性,其降解速率常数k为5.5×10^-2min^-1,是HRP的14.8倍。光催化机理探究发现,ZnO和HRP复合形成异质结后,可抑制光生电子和空穴的复合,增强光响应性,从而提高了HRP的光催化活性。

The p-type semiconductor red phosphorus(HRP)and the n-type semiconductor ZnO are combined to form a p-n type heterojunction composite semiconductor catalyst ZnO/HRP.Cr(Ⅵ)is selected as a model pollutant to investigate the effect of ZnO content on the photocatalytic reduction performance of the catalyst.It is found that the photocatalytic reduction speed of ZnO/HRP composite photo catalyst is enhanced with the increase of ZnO mass fraction in the catalyst,and decreases after reaching the highest value.When the mass fraction of ZnO is 0.25%,ZnO 0.25/HRP composite photo catalyst exhibits the strongest photocatalytic reduction activity.Its reduction rate can achieve 5.5×10^-2 min^-1,14.8 times that of HRP.It is found through studying the photocatalytic mechanism that a heterojunction formed by ZnO and HRP can inhibit the recombination of photogenerated electrons and holes,and enhance the light responsiveness,thus improving the photocatalytic activity of HRP.