化工学报 ›› 2022, Vol. 73 ›› Issue (11): 4998-5010.DOI: 10.11949/0438-1157.20220912

• 催化、动力学与反应器 • 上一篇    下一篇

Ni2+取代对ZnTi-LDH选择性光氧化去除NO的性能增强

杜智华1(), 杨娟1,2(), 戴俊1,2, 冷冲冲1, 张鸽1   

  1. 1.河南理工大学安全科学与工程学院,河南 焦作 454003
    2.煤炭安全生产与清洁高效利用省部共建协同创新中心,河南 焦作 454003
  • 收稿日期:2022-06-29 修回日期:2022-10-07 出版日期:2022-11-05 发布日期:2022-12-06
  • 通讯作者: 杨娟
  • 作者简介:杜智华(1998―),女,硕士研究生,zhihuadu@home.hpu.edu.cn
  • 基金资助:
    国家自然科学基金项目(52074103);河南省自然科学基金项目(202300410181);河南省科技攻关重点项目(222102320095);河南省高等学校重点科研项目(21A440008)

Performance enhancement of selective photo-oxidation for NO removal on ZnTi-LDH by Ni2+ substitution

Zhihua DU1(), Juan YANG1,2(), Jun DAI1,2, Chongchong LENG1, Ge ZHANG1   

  1. 1.School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, Henan, China
    2.State Collaborative Innovation Center of Coal Work Safety and Clean-efficiency Utilization, Jiaozuo 454003, Henan, China
  • Received:2022-06-29 Revised:2022-10-07 Online:2022-11-05 Published:2022-12-06
  • Contact: Juan YANG

摘要:

以NiCl2·6H2O为镍源,采用水热法首次合成了不同Ni2+取代量的锌钛层状双金属氢氧化物(NiZnTi-LDH),通过X射线衍射、透射电镜、低温氮吸附、X射线光电子能谱与紫外-可见漫反射等测试研究了Ni2+取代对ZnTi-LDH晶相结构、微观形貌、孔结构、表面氧空位与光吸收性能的影响。以NiZnTi-LDH为催化剂,分别考察了模拟太阳光与可见光照射下的NO光氧化消除性能。结果表明:Ni2+部分取代Zn2+可在ZnTi-LDH的能带结构中形成一新的中间能级,产生可见光响应,同时Ni取代可于ZnTi-LDH表面形成氧空位(OV)。可见光照射下,ZnTi-LDH无NO氧化活性,最优催化剂27% NiZnTi-LDH的NO去除率为52.1%,NO x 脱除选择性高达97.4%。模拟太阳光照射下,27% NiZnTi-LDH的NO光氧化去除率为64.8%,是ZnTi-LDH的2.76倍,NO x 脱除选择性可达96.9%,且NO3-生成量占总硝酸盐的95.6%。Ni2+取代及由此形成的OV不仅促进光生电荷分离,同时利于超氧自由基(·O2-)的生成,在增强NO消除性能的同时,抑制有毒NO2的产生,实现NO至NO3-的深度光氧化。

关键词: 锌钛LDH, 镍取代, 深度光氧化, 一氧化氮, 氧空位, 性能增强

Abstract:

Ni-substituted Zn-Ti layered double hydroxide (NiZnTi-LDH) with different Ni2+ substitution ratios were firstly synthesized by using NiCl2·6H2O as nickel source via hydrothermal method. The effects of Ni2+ substitution on the crystal phase, morphology, pore structure, surface oxygen vacancy and light absorption properties of ZnTi-LDH were investigated by X-ray diffraction, transmission electron microscopy, low temperature nitrogen adsorption, X-ray photoelectron spectroscopy and UV-visible diffuse reflectance. Using NiZnTi-LDH as catalyst, the photo-oxidation and elimination performance of NO under simulated sunlight and visible light irradiation were investigated respectively. The results showed that partial Ni2+ substitution for Zn2+ formed a new intermediate energy level in the band structure of ZnTi-LDH that consequently produced visible light response, meanwhile Ni2+ substitution generated oxygen vacancies (OV) on ZnTi-LDH surface. Under visible light irradiation, ZnTi-LDH had no NO oxidation activity, and the optimal 27% NiZnTi-LDH catalyst showed a NO removal rate of 52.1% with a De-NO x selectivity up to 97.4%. Under simulated solar light irradiation, 27% NiZnTi-LDH exhibited a NO photo-oxidation removal rate of 64.8% that was 2.76 times of ZnTi-LDH and De-NO x selectivity was 96.9%, meanwhile the produced NO3- accounted for 95.6% of total nitrate. Ni2+ substitution and the resulting OV not only promoted the separation of photogenerated carriers, but also facilitated the generation of superoxide radical (·O2-). As a result, the photo-oxidative activity of NO removal was enhanced and the production of toxic NO2 was effectively inhibited, consequently achieving deep photo-oxidation of NO to NO3-.

Key words: ZnTi-LDH, Ni2+-substitution, deep photo-oxidation, NO, oxygen vacancy, performance enhancement

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