pH-Controlled photocatalytic abatement of RhB by an FeWO4/BiPO4 p–n heterojunction under visible light irradiation

Abstract

A novel p–n heterostructure of an FeWO₄/BiPO₄ nanocomposite was designed and synthesized through a simple hydrothermal method. Among all the nanocomposites prepared with different weight percentages of FeWO₄, 30% FeWO₄/BiPO₄ (S3) showed the highest photocatalytic performance for the degradation of Rhodamine B and tetracycline under visible light irradiation. The degradation efficiency of RhB for the S3 sample was 87% under neutral conditions within 300 min but interestingly, at pH 3, 99% degradation efficiency was observed within 30 min with good recyclability. The enhanced photocatalytic performance should be due to the maximum electron–hole pair decoupling efficiency of the S3 catalyst. The mineralization of RhB during the catalytic process was detected by GC-MS. Consequently, based on the experimental results, a possible photocatalytic mechanism over the FeWO₄/BiPO₄ composite was anticipated, which indicated the substantial potential of the composite for the treatment of textile and pharmaceutical wastewater.