Ting Gao,Jingqi Lin,Ke Zhang,Mohsen Padervand,Yifan Zhang,Wei Zhang,Menglin Shi,Chuanyi Wang
Since conventional techniques are ineffective for NO removal at low concentrations, photocatalysis has become attractive in this regard, recently. However, in practice, photocatalytic NO removal has drawbacks such as limited light absorption and the proclivity of producing toxic by-products. To address these issues, novel defective Bi/Bi3NbO7structures with good porosity were fabricated by a solvothermal method and used for enhanced photocatalytic NO removal under visible light irradiation. The morphological and structural properties of the prepared materials were comprehensively analyzed. The optimal photocatalytic activity of pore-defective Bi/Bi3NbO7for NO removal was 60.3%, when the molar ratios of urea and Bi(NO)3•5H2O to pristine Bi3NbO7were 1:25 and 1:2, respectively, under the following operational conditions: NO concentration of 700 ppb, catalyst dosage of 50 mg and irradiation time of 14 min. The induced defects and the surface plasmon resonance (SPR) effect of Bi nanodots made remarkable contributions to improving the photocatalytic NO removal as well as inhibiting the toxic byproduct NO2. The photocatalytic NO removal pathway over the prepared photocatalysts was further mechanistically clarified taking advantage of EPR results and scavenging experiments. Considering the increased NO generation in the atmosphere, this work may provide novel insights for designing effective porous photocatalysts to treat gaseous toxic pollutants.Keywords:photocatalysis;Bi3NbO7;surface plasmon resonance;NO removal;defects
Yao Wang,Pengzhan Zhang,Fan Li,Liang Zhang,Bing Xu,Kangkang Wang,Zhixian He,Yuyan Sun,Shengnan Zhang
Bi 3 NbO 7 loaded on porous carbon (BNO/PC) composite materials has been prepared by the in-suit sol-gel method. The photocatalytic efficacy of the BNO/PC composite has been evaluated by degrading tetracycline (TC) in an environment of visible light and hydrogen peroxide. Moreover, the relevant influencing factors of TC degradation efficiency have been explored through a series of condition optimization experiments. UV–vis DRS and PL tests showed that the loading on porous carbon significantly broadens the visible light response range of the catalyst and improves the separation efficiency of photogenerated carriers. Compared with the bare BNO, the specific surface area and average pore diameter of the BNO/PC composite material increased greatly. The optimal sample of 35 % BNO/PC exhibited outstanding visible light response ability and excellent charge separation efficiency. The “cata + H 2 O 2 +vis” system had the highest photocatalytic activity, with TC degradation reaching 86.9 % after 60 min of visible light illumination. The addition of hydrogen peroxide (H 2 O 2 ) promoted the formation of more powerful active substances. Following this, a mechanism for photocatalytic degradation has been proposed.
LaFeO 3 /Bi 3 NbO 7 p-n heterojunction photocatalysts were prepared successfully through an in-situ growth method. The phase structure, optical property , morphology and microstructures of the obtained samples were studied by X-Ray diffractometer (XRD), Ultraviolet–visible absorption spectrum (UV–vis DRS), photoluminescence (PL) spectroscopy, transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM) and scanning electron microscope (SEM). The visible light responsive photocatalytic activity of as-obtained samples were investigated by the photo-reduction of Cr (Ⅵ). The effects of preparation conditions (proportion of BNO/LFO and temperature) on the activity were studied. Results showed that the as-obtained BNO-LFO-200-5 composite behaved the best photocatalytic activity (with rate constant of 0.0212 min −1 ) among all the obtained samples. The rate constant was about 42.4-times and 17.7-times as that of pristine BNO (0.0005 min −1 ) and LFO (0.0012 min −1 ), respectively. The enhanced photocatalytic property of the as-prepare LaFeO 3 /Bi 3 NbO 7 composites can be ascribed to the formation of p-n junction between BNO and LFO, which significantly increased the separation efficiency of photo-excited electron-holes.
Lianpeng Song,Zhong Liang,Mingzi Sun,Bolong Huang,Yaping Du
The selectivity in the electrocatalysis of carbon dioxide reduction reaction (CO2RR) has attracted tremendous attention but still faces a great challenge. Constructing an interface has become an advanced strategy to effectively modulate electroactivity and selectivity. Herein, we report the synthesis of a CeO2/Bi3NbO7 fibrous tubular structure through a simple electrospinning method, which has shown a much-improved selectivity of 84.73% towards formic acid with remarkable durability in the CO2RR. Theoretical calculations have demonstrated that the construction interface has supplied highly electroactive regions with efficient electron transfer, which not only improves the adsorption of key adsorbates but also alleviates the reaction energy barriers. The modulation induced by the interface enables the high selectivity and yield of HCOOH. This work has supplied a novel and advanced strategy to utilize the interfacial effect in developing superior CO2RR electrocatalysts in the future.
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