Synergistic effect of homojunction and Ohmic junctions in CdS boosting spatial charge separation for U(VI) photoreduction
Haonan Pei, Zhimin Dong, Zifan Li, Jian Huang, Yuanping Jiang, Zuojia Li, Lin Xu, Xiaohong Cao, Yunhai Liu, Zhibin Zhang, Guo‐Ping Yang
Abstract
Photo-excited holes usually migrate to the surface of the catalyst and rapidly recombine with electrons, reducing the photocatalytic reduction efficiency of uranium(VI) (U(VI)) in radioactive wastewater. Consequently, we employed a straightforward synthesis technique to meticulously shape and manipulate the morphology of CdS to precisely construct CdS-Ni dandelion-like composites with different aspect ratios. Briefly, the introduction of crystal facet homojunction with Ohmic contacts in this unique morphology siqnificantly improves the photocatalytic efficiency. Temperature-dependent photoluminescence spectroscopy (TD-PL) verifies that the composite material positively effects on the dissociation of excitons. Within 30 min, CdS(002)/(102)/Ni-4 removed 98% of the uranium content in solution and showed a rather high apparent rate constant (0.114 min −1 ), which was 4.8 times higher than that of CdS nanospheres (NSs) (0.024 min −1 ) and 3.7 times higher than that of CdS nanorods (NRs) (0.031 min −1 ). This is much higher the most reported photocatalysts for U(VI) reduction. Even after 5 consecutive cycles, the photocatalytic efficiency only decreased by 7%. This offers a fresh perspective on constructing a new perspective for building a green, efficient, and multi mechanism collaborative catalytic system to remediate environmental pollution.