Du Yu-Bing,Wang Nan,Li Xiang-Nan,Li Juan,Wu Liang-Peng,Peng Quan-Ming,Li Xin-Jun
Construction of high-efficient and low-cost heterostructure photocatalyst is crucial for hydrogen production in solar driven water splitting. Herein, g-C 3 N 4 -modified TiO 2 nanotubes (TNTs) with confined Pt nanoparticles were prepared via a facile two-step process. The results of structure characterizations by XRD, TEM, and XPS reveal that Pt nanoparticles with the average size of 2–3 nm are embedded in the inner cavity of the TiO 2 nanotube, and amorphous g-C 3 N 4 is attached to the outer wall of anatase TNTs. The as-prepared g-C 3 N 4 /TNTs@Pt ternary composite displays an enhanced visible light-induced absorbance capacity and improved charge carrier recombination rate than that of pure TNTs. The photocatalytic performance is evaluated by hydrogen evolution from water splitting by using methanol as sacrifice agent under solar light illumination. Compared with TNTs@Pt and g-C 3 N 4 /Pt photocatalysts, the as-prepared ternary nanocomposite exhibits the highest photocatalytic performance with a H 2 evolution rate of 15.36 mmol h −1 g −1 . A possible mechanism of photocatalytic H 2 production over the ternary g-C 3 N 4 /TNTs@Pt composite is also proposed. This work not only provides a promising low-cost heterostructure candidate for water splitting, but also paves the way to rational design high-performance photocatalysts in solar-to-fuel conversion.
He Zhang,Wenmei Luo,Yuping Du,Hao Shi,Guangyong Zeng,Xinxing Yan,Xiaoke Li
Although solar steam generation (SSG) technology has shown promising advantages in the desalination of seawater, the treatment of organic pollutants in wastewater using SSG technology remains a challenge. Furthermore, the efficacy of evaporation materials is often hindered by the presence of organic pollutants, thereby limiting their practical application in the desalination of high-salinity wastewater. To address this issue, a synergistic approach combining photoevaporation and photocatalysis has been proposed as a potential solution. In this study, a novel rGO/MWCNTs aerogel (GMA) modified by photocatalyst g-C 3 N 4 was fabricated by hydrothermal synthesis in the integrated treatment of unconventional waters. At one solar radiation (1 kW·m −2 ), GMA achieved an evaporation rate of 2.07 kg·m −2 ·h −1 and a remarkable solar evaporation efficiency of 92.7 %. In addition, GMA demonstrated excellent desalination performance with over 98 % removal of waste metal ions from seawater and brackish water after desalination. First applied aerogel to the lithium chloride wastewater evaporation and concentration, achieving the concentration of lithium chloride wastewater from 700 mg/L to 5.18 g/L. Additionally, the coordinated photocatalysis of g-C 3 N 4 and rGO resulted in catalytic degradation rates of RhB and TB up to 91.6 % and 87.9 %, respectively. This study provides a new idea for SSG technology in high-salinity wastewater treatment .
Photocatalytic property of nano Ag is weak and its enhancement is important to enlarge its application. Herein, a novel strategy of constructing silver g-C 3 N 4 biochar composite (Ag-CN@BC) as photocatalyst is developed and its photocatalytic degradation of bisphenol A (BPA) coupled with peroxydisulfate (PDS) oxidation process is characterized. Characterization result showed that silver was evenly embedded into the g-C 3 N 4 structure of the nitrogen atoms format, impeding agglomeration of Ag by distributing stably on biochar. In optimum condition, BPA of 10 mg/L could be degraded completely at pH of 9.0 with a 0.5 g/L photocatalyst, 2 mM PDS in Ag-CN@BC-2 (Ag/melamine molar ratio of 0.5)/PDS system (99.2%, k = 4.601 h −1 ). Ag-CN@BC shows superior mineralization ratio in degrading BPA to CO₂ and H₂O via active radical way, including holes ( h ⁺), superoxide radicals (•O 2 ⁻ ), sulfate radicals (SO 4 • ⁻ ), and hydroxyl radicals (•OH). Proper amount of silver can be dispersed effectively by gC 3 N 4 , which is responsible for improving the visible-light absorbing capability and accelerate charge transfer during activation of PDS for BPA degradation, while biochar as carrier in the composite is supposed to enhance the photoelectric degradation of BPA by reducing the band gap and increasing the photocurrent of Ag-CN@BC catalyst. Ag-CN@BC exhibits excellent catalyst stability and photocatalytic activity for treatment of toxic organic contaminants in the environment.
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