A direct Z-scheme g-C3N4/SnS2 photocatalyst with superior visible-light CO2 reduction performance
A direct Z-scheme g-C3N4/SnS2 photocatalyst with superior visible-light CO2 reduction performance
复制标题
具有卓越可见光二氧化碳减排性能的直接 Z 型 g-C3N4/SnS2 光催化剂
DOI：
10.1016/j.jcat.2017.06.006
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发表时间：
2017-08-01
影响因子：
7.3
通讯作者：
Xu, Jingsan
中科院分区：
文献类型：
--
作者：
Di, Tingmin;Zhu, Bicheng;Xu, Jingsan
将CO2光催化还原为太阳能燃料是同时解决全球变暖和能源危机问题的理想途径。构建直接Z型异质结是克服单组分或传统多相光催化剂在光催化还原CO2方面的缺点的有效途径。在此，通过简单的一步水热法在g-C3 N4表面原位沉积SnS 2量子点，构建了一种新型的直接Z型g-C3 N4/SnS 2异质结。L-半胱氨酸不仅作为硫源，而且在水热过程中将氨基接枝到g-C3 N4上，大大提高了复合材料的CO2吸收能力。XPS分析和密度泛函理论（DFT）计算表明，在平衡状态下，g-C3 N4与SnS 2之间发生了电子转移，形成了界面内电场（IEF）。结果表明，在光激发下，SnS 2中的电子与g-C3 N4中的空穴发生了Z型电荷转移，提高了g-C3 N4中光生电子的提取和利用率。与单独的g-C3 N4和SnS 2相比，g-C3 N4/SnS 2杂化物显示出上级光催化CO2还原，这应归因于IEF诱导的直接Z方案以及改善的CO2吸附能力。原位红外光谱表明，HCOOH是CO2转化过程中的中间产物，根据光生电子的能级，HCOOH只能由g-C3 N4生成，进一步证实了gC（3）N（4）/SnS 2体系的Z构型. (C)2017爱思唯尔公司All rights reserved.
Photocatalytic reduction of CO2 to solar fuels is an ideal approach to simultaneously solve the global warming and energy crisis issues. Constructing a direct Z-scheme heterojunction is an effective way to overcome the drawbacks of single-component or conventional heterogeneous photocatalysts for photo catalytic CO2 reduction. Here, a novel type of direct Z-scheme g-C3N4/SnS2 heterojunction was constructed by depositing SnS2 quantum dots onto the g-C3N4 surface in situ via a simple one-step hydrothermal method. L-Cysteine not only acted as the sulfur source, but also grafted ammine groups onto g-C3N4 in the hydrothermal process, which greatly enhanced the CO2 uptake of the composite. XPS analysis and density functional theory (DFT) calculation show that electron transfer occurred from g-C3N4 to SnS2, resulting in the formation of interfacial internal electric fields (IEF) between the two semiconductors at equilibrium. As a result, Z-scheme charge transfer took place under photoexcitation, with the electrons in SnS2 combining with the holes in g-C3N4, which improved the extraction and utilization of photoinduced electron in g-C3N4. The g-C3N4/SnS2 hybrid shows superior photocatalytic CO2 reduction as compared with individual g-C3N4 and SnS2, which should be attributed to the IEF-induced direct Z scheme as well as improved CO2 adsorption capacity. In situ FTIR spectra illustrate that HCOOH appeared as an intermediate during the CO2 conversion, which can only be generated by g-C3N4 according to the energy level of the photoinduced electrons, further confirming the Z-scheme configuration for the gC(3)N(4)/SnS2 system. (C) 2017 Elsevier Inc. All rights reserved.