Revealing the Double‐Edged Sword Role of Graphene on Boosted Charge Transfer versus Active Site Control in TiO2 Nanotube Arrays@RGO/MoS2 Heterostructure,Small

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Revealing the Double‐Edged Sword Role of Graphene on Boosted Charge Transfer versus Active Site Control in TiO2 Nanotube Arrays@RGO/MoS2 Heterostructure
Small ( IF 13.0 ) Pub Date : 2018-04-18 , DOI: 10.1002/smll.201704531
Quan Quan _{1,

2} , Shunji Xie ₃ , Bo Weng _{1,

2} , Ye Wang ₃ , Yi-Jun Xu _{1,

2}

Affiliation

Charge separation/transfer is generally believed to be the most key factor affecting the efficiency of photocatalysis, which however will be counteracted if not taking the active site engineering into account for a specific photoredox reaction. Here, a 3D heterostructure composite is designed consisting of MoS₂ nanoplatelets decorated on reduced graphene oxide‐wrapped TiO₂ nanotube arrays (TNTAs@RGO/MoS₂). Such a cascade configuration renders a directional migration of charge carriers and controlled immobilization of active sites, thereby showing much higher photoactivity for water splitting to H₂ than binary TNTAs@RGO and TNTAs/MoS₂. The photoactivity comparison and mechanistic analysis reveal the double‐edged sword role of RGO on boosted charge separation/transfer versus active site control in this composite system. The as‐observed inconsistency between boosted charge transfer and lowered photoactivity over TNTAs@RGO is attributed to the decrease of active sites for H₂ evolution, which is significantly different from the previous reports in literature. The findings of the intrinsic relationship of balanced benefits from charge separation/transfer and active site control could promote the rational optimization of photocatalyst design by cooperatively manipulating charge flow and active site control, thereby improving the efficiency of photocatalysis for target photoredox processes.

中文翻译：

揭示石墨烯在TiO2纳米管阵列@ RGO / MoS2异质结构中对促进电荷转移与活性位点控制的双刃剑作用

通常认为电荷分离/转移是影响光催化效率的最关键因素，但是，如果不将活性位点工程考虑到特定的光氧化还原反应中，则该电荷分离/转移将被抵消。在这里，设计了一种3D异质结构复合材料，该复合材料由装饰在还原的氧化石墨烯包裹的TiO ₂纳米管阵列（TNTAs @ RGO / MoS ₂）上的MoS ₂纳米片组成。这种级联构型使电荷载流子定向迁移并控制了活性位点的固定，因此与二元TNTAs @ RGO和TNTAs / MoS ₂相比，水分解为H _2的光活性更高。。光活性的比较和机理分析揭示了在该复合系统中，RGO在增强电荷分离/转移与活性位点控制方面的双刃剑作用。在TNTAs @ RGO上观察到的电荷转移增强和光活性降低之间的不一致，是由于H ₂析出的活性位点减少所致，这与文献中先前的报道有显着差异。通过电荷操纵和活性位点的协同控制，电荷分离/转移与活性位点控制之间的平衡利益内在关系的发现可以促进光催化剂设计的合理优化，从而提高目标光氧化还原过程的光催化效率。

更新日期：2018-04-18

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