Lu Zhang,Meng Zhang,Xiaozhe Song,Hui Wang,Zhaoyong Bian
Here, we report enhancement of the photoelectrochemical (PEC) performance of MnO x /graphite-like carbon nitride (g-C 3 N 4 ) nanocomposites synthesized by one-step thermal decomposition for degradation of clofibric acid (CA). MnO x showed enhanced broadband ultraviolet–visible light regions, efficient charge generation–separation, and enhanced PEC performance when combined with g-C 3 N 4 . Photogenerated holes can be efficiently captured by introducing Mn 2+ /Mn 3+ /Mn 4+ valence band transitions. In addition to a good visible-light response, the MnO x /g-C 3 N 4 -10 (g-C 3 N 4 with 10% Mn(NO 3 ) 2 ·6H 2 O) photoanode showed enhanced photocurrent density of 0.03 × 10 −3 A cm −2 at 0.63 V vs. Ag/AgCl, which was approximately 100 times that of pristine g-C 3 N 4 . The superoxide radical and positive holes played dominant roles in PEC degradation of CA. The MnO x /g-C 3 N 4 -10 photoanode showed the highest photoelectrocatalytic performance under acidic conditions because of electrostatic attraction between the electrode and CA. The CA degradation ratio using the MnO x /g-C 3 N 4 -10 photoanode was 100% under visible light in 6 h at pH = 3. This work provides a simple and sustainable strategy to modify g-C 3 N 4 for captured holes to improve PEC degradation of CA, and it is promising for application to different materials in a variety of fields.
The degradation of ofloxacin (OFX) at low concentration in aqueous solution by UVA-LED/TiO 2 nanotube arrays photocatalytic fuel cells (UVA-LED/TiO 2 NTs PFCs) was investigated. TiO 2 nanotube arrays (TiO 2 NTs) photoanode prepared by anodization-constituted anatase–rutile bicrystalline framework. The results indicated that the degradation efficiency of OFX by UVA-LED/TiO 2 NTs PFC was significantly enhanced by 14.3% compared with UVA-LED/TiO 2 NTs photocatalysis. The pH affected the degradation efficiency markedly; the highest degradation efficiency (95.0%) and the pseudo-first-order reaction rate constant k value (0.049 min −1 ) were achieved in neutral condition (pH 7.0). The degradation efficiency increased with the increasing concentration of dissolved oxygen (DO) in the UVA-LED/TiO 2 NTs PFC. The main reactive species of OFX degradation are positive holes (h + ) and superoxide ion radicals (O
·− 2
) in a DO sufficient condition. Furthermore, the possible pathways of OFX degradation were proposed.
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