Enhanced visible light photocatalytic reduction of cr (vi) by bi2wo6 nanosheet/cufe2o4 nanofiber heterojunctions by Musa, Makiyyu Abdullahi, Shao, Hong, Xu, Da, Sun, Feng, Dong, Xiangting, Azis, Raba'ah Syahidah, Ugya, Adamu Yunusa, Ari, Hadiza Abdullahi