Photocatalytic CO2 reduction on porous TiO2 synergistically promoted by atomic layer deposited MgO overcoating and photodeposited silver nanoparticles
Photocatalytic CO2 reduction on porous TiO2 synergistically promoted by atomic layer deposited MgO overcoating and photodeposited silver nanoparticles
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DOI：
10.1016/j.cattod.2019.03.012
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发表时间：
2020
期刊：
影响因子：
5.3
通讯作者：
Xuhui Feng;Fuping Pan;Brandon Z. Tran;Ying Li
中科院分区：
文献类型：
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作者：
Xuhui Feng;Fuping Pan;Brandon Z. Tran;Ying Li
本文以金属有机骨架MIL-125为载体，制备了一种多孔TiO 2光催化剂，并对其进行了光催化还原CO2的实验研究。为了提高光催化性能，采用原子层沉积（ALD）MgO外涂层和光沉积银（Ag）纳米颗粒修饰TiO 2，并以不同顺序进行修饰：先沉积MgO后沉积Ag（即Ag/MgO/TiO 2），或先沉积Ag后沉积MgO（即MgO/Ag/TiO 2）。Ag的加入促进了光生电子的转移，而MgO涂层抑制了表面电荷复合，增强了CO2的吸附。MgO和Ag的组合对CO2光还原的协同促进作用大于单独促进作用的总和。Ag/MgO/TiO 2催化剂的活性比纯TiO 2催化剂高14倍。此外，MgO/Ag修饰顺序对催化剂的活性也有影响。Ag/MgO/TiO 2催化剂比MgO/Ag/TiO 2催化剂的活性更高，这可能是由于电子迁移率和Ag纳米颗粒在表面的分布不同。本工作首次报道了ALD包覆MgO和光沉积Ag纳米颗粒在TiO 2上的新型材料结构，揭示了优化材料形貌和结构对提高催化活性的重要性。
In this work, a porous TiO2photocatalyst derived from metal-organic framework MIL-125 was synthesized and tested for photocatalytic CO2reduction with water. To improve the photocatalytic performance, innovative materials modifications were employed by decorating TiO2with atomic layer deposited (ALD) MgO overcoating and photodeposited silver (Ag) nanoparticles at different orders: MgO deposition followed by Ag (i.e. Ag/MgO/TiO2), or Ag deposition followed by MgO (i.e. MgO/Ag/TiO2). The addition of Ag promoted transfer of photoinduced electrons, while the coating of an ultrathin MgO layer inhibited surface charge recombination and enhanced CO2adsorption. The combination of MgO and Ag resulted in synergistic promotion on CO2photoreduction greater than the sum of individual promotional effects. The Ag/MgO/TiO2catalyst with 7 ALD-layers of MgO and 5% Ag was 14 times more active than the pristine TiO2in terms of CO and CH4production. In addition, the sequence of MgO/Ag decoration influenced the catalytic activity. The Ag/MgO/TiO2catalysts were in general more active than the MgO/Ag/TiO2counterparts, likely due to the different electron mobility and Ag nanoparticle distribution on the surface. This work for the first time reports the novel materials structure of ALD coated MgO and photodeposited Ag nanoparticles on TiO2, and it reveals the importance of optimizing materials morphology and structure to promote the catalytic activity.