High efficient photocatalytic reduction of nitrate to N2 by Core-shell Ag/SiO2@cTiO2 with synergistic effect of light scattering and surface plasmon resonance
High efficient photocatalytic reduction of nitrate to N2 by Core-shell Ag/SiO2@cTiO2 with synergistic effect of light scattering and surface plasmon resonance
复制标题
光散射和表面等离子体共振协同作用的核壳Ag/SiO2@cTiO2高效光催化还原硝酸盐为N2
DOI：
10.1016/j.cej.2021.128863
复制
发表时间：
2021-02-18
影响因子：
15.1
通讯作者：
Francois-Xavier, Corvini Philippe
中科院分区：
文献类型：
--
作者：
Hou, Zhiang;Chu, Jiangfeng;Francois-Xavier, Corvini Philippe
光催化脱氮以其高效、环保的特点受到了广泛的关注。然而，由于硝酸盐和光催化剂之间的光子竞争，将高浓度硝酸盐选择性光催化还原为N-2仍然是一个具有挑战性的问题。本文构建了包裹在TiO2晶壳（Ag/SiO2@cTiO(2)）中的Ag/SiO2核，以提高光催化脱氮性能。时域有限差分（FDTD）仿真表明，强光散射改善了光约束的光捕获。同时，Ag的表面等离子体共振和电子汇效应不仅提高了光生电子密度，而且促进了Ag/SiO2@cTiO载流子的分离(2)。更重要的是，tio2 -壳的e(cb)（-）可以立即转移到Ag上，保持Ag-0和Ag+之间的平衡，这有助于Ag/SiO2@cTiO具有良好的稳定性(2)。5 wt%Ag/SiO2@cTiO(2)在4 h内脱除了95.8%的硝酸盐（C-0 = 2000 mg/L）， N-2选择性为93.6%。即使在5个循环后，5 wt%Ag/SiO2@cTiO(2)仍保持了较高的光催化脱氮效率（92.2%）。值得注意的是，由于TiO2-shell阻止了Ag与Cl-的反应，在高浓度Cl-存在下，5.3 h内硝酸盐的去除率可达92%以上。
Photocatalytic denitrification has attracted great attention owing to its high efficiency and environmentally friendly features. However, selectively photocatalytic reduction of high concentration nitrate to N-2 is still a challenging problem due to the competition of photons between nitrate and photocatalysts. Herein, the Ag/SiO2 core encapsulated in the crystalline TiO2 shell (Ag/SiO2@cTiO(2)) was constructed for improvement of photocatalytic denitrification. Finite difference time domain (FDTD) simulation demonstrated that strong light scattering improved light harvesting via optical confinement. Meanwhile, surface plasmon resonance and electron sink effect of Ag not only enhanced the photogenerated electrons density but also promoted charge carriers separation of Ag/SiO2@cTiO(2). More importantly, e(cb)(-), of TiO2-shell could be immediately transferred to Ag to keep the balance between Ag-0 and Ag+, which contributed to the good stability of Ag/SiO2@cTiO(2). 95.8% nitrate (C-0 = 2000 mg/L) was removed by 5 wt%Ag/SiO2@cTiO(2) with N-2 selectivity of 93.6% within 4 h. Even after five cycles, 5 wt%Ag/SiO2@cTiO(2) still remained high photocatalytic denitrification efficiency (92.2%). Notably, since TiO2-shell prevented the reaction between Ag and Cl-, more than 92% nitrate could be removed within 5.3 h in the presence of high concentration Cl-.