The synthesis of Vis-light driven catalysts with high photocatalytic performance and efficient activation of persulfate requires new strategies. Herein, a multistage structural tuning graphitic carbon nitride co-modified by Co, S (pg-C 3 N 4 /Co 3 O 4 /CoS) was synthesized for the first time through in-situ template method and microwave sulfurization treatment. A photocatalysis-PMS oxidation coupling system was also proposed. The results showed that the introduction of cobalt could improve the photocatalysis and PMS activation efficiency of the graphitic carbon nitride. Further sulfurization treatment could generate more active sites for PMS activation and increase the interlayer distance of carbon nitride to broaden the absorption range of Vis-light. Density functional theory (DFT) calculations indicated the migration of electrons from carbon nitride to CoS promoted the recycling of Co 3+ /Co 2+ . In the coupling system, BPF 50 mL (30 mg L -1 ) was degraded by 99% in 10 min with 0.1 g L -1 catalyst and 0.32 mmol L -1 PMS. The degradation rate was 4 times faster than that of pure PMS system under visible light. Notably, BPF was effectively mineralized and TOC removal rate reached 90%. The stability and recycling experiments showed that pg-C 3 N 4 /Co 3 O 4 /CoS maintained high catalytic performance under complex matrix and multiple cycles, and could be quickly separated and recovered due to the magnetic Co 3 O 4 . This work will provide a new strategy for the development of multi performance catalytic materials, and the proposed photocatalysis-PMS coupling system has huge potential for the wastewater treatment.
Transition metal co-catalysts exhibit considerable potential in the photocatalytic water splitting process, but their limited activity and poor stability inhibit their extensive application, and therefore effective schemes are required to further enhance their co-catalytic performance. In this article, 2D/2D C3N4/CdS heterogeneous photocatalysts are first synthesized, and then CoNi alloyed NPs are selectively loaded on their CdS nanosheets by a convenient photodeposition method. The CoNi loading amount and Co/Ni ratio are adjusted by the photodeposition time and precursor Co2+/Ni2+ ratio, respectively. Meanwhile, Co–S bonds are formed between CdS and CoNi NPs. Their optimal hydrogen evolution rate can reach up to 2936.65 μmol g−1 h−1, which is higher than that of C3N4/CdS with Co, Ni or Pt as co-catalysts (i.e. 844.59, 2385.96 and 2486.66 μmol g−1 h−1), respectively. The enhanced photocatalytic performance should be due to the following three points: (1) the formation of the 2D/2D C3N4/CdS heterojunction; (2) the optimized Gibbs free energy of the CoNi co-catalysts; (3) the formation of Co–S bonds between CoNi and CdS. Our work provides a cost-effective scheme to exploit stable and efficient photocatalysts.
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