Degrading dye waste using inexpensive synthetic photocatalysts is intriguing since it provides the dual advantage of treating water and managing waste simultaneously. There is considerable interest in the construction of heterojunctions for their efficiency in using solar energy for the degradation of wastewater contaminants and enhancing the solar conversion efficiency. Herein, BiVO4 microspheres and 2D g-C3N4 nanosheets were used to synthesize a direct Z-scheme BiVO4/g-C3N4 heterojunction through a hydrothermal calcination approach. The distinct 0D/2D intimate contact heterostructure displayed a high interfacial area and broader visible-light absorption range together with high photoexcited charge pair mobility. Optimizing the content of the BiVO4 microspheres in the heterostructure led to the maximum efficiency for the visible-light photodegradation of rhodamine B (RhB), which was about 12.5 and 2.4 times higher than that for pure BiVO4 and g-C3N4, respectively. Moreover, the quenching effects of various scavengers demonstrated that ˙O2− and ˙OH radicals were the principal active species responsible for ameliorating the photocatalytic performance for RhB degradation. The demonstrated strategy for boosting the photocatalytic performance with Z-scheme systems may help the advancement of high-performance photocatalysts for sustainable and efficient pollutant degradation and energy applications.
Xudong Yin,Xiaojie Sun,Yufeng Mao,Ruzhen Wang,Dehao Li,Wenyu Xie,Zhenghui Liu,Zhisen Liu
The elimination of tetracycline hydrochloride (TC-HCl) from water has attracted extensive research attention. This study hydrothermally synthesized composite photocatalysts composed of BiVO 4 microspheres containing coexisting phases of monoclinic scheelite (M-BiVO 4 ) and tetragonal zircon (T-BiVO 4 ), i.e., MT-BiVO 4 , loaded onto P-doped g-C 3 N 4 nanosheets (PCNS). Furthermore, their morphology, structure, and photoelectrochemical properties were comprehensively characterized, and the performance and stability of photocatalytic degradation of TC-HCl were examined. Additionally, the effects of humic acid (HA), coexisting anions/cations, and actual water samples on the degradation efficiency of TC-HCl were investigated, and the degradation mechanism and pathways were examined. The findings indicated that the percentage of M-BiVO 4 in MT-BiVO 4 considerably influences the photocatalytic activity of the composite catalyst. Furthermore, the excellent photocatalytic performance of 5% BVO/PCNS was attributed to the synergistic effects of P-doping the modified g-C 3 N 4 , MT-BiVO 4 isotype heterojunction effects, and the Z-scheme heterojunction constructed from MT-BiVO 4 and PCNS, which can enhance the absorption range of the visible light and accelerate the transfer and separation of charge carriers between catalysts. The free radical capture experiments and electron spin resonance tests indicated that holes and O 2 - were the dominant active species in the photocatalytic degradation process. With high reusability and stability, the 5% BVO/PCNS composite has great potential for practical wastewater treatment applications. This study offers a new approach for preparing photocatalysts synergized by isotype and Z-scheme heterojunctions.
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