Ultrathin ZnIn2S4 nanosheets with active (110) facet exposure and efficient charge separation for cocatalyst free photocatalytic hydrogen evolution
Ultrathin ZnIn2S4 nanosheets with active (110) facet exposure and efficient charge separation for cocatalyst free photocatalytic hydrogen evolution
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具有活性 (110) 面暴露和高效电荷分离的超薄 ZnIn2S4 纳米片，用于无助催化剂的光催化析氢
DOI：
10.1016/j.apcatb.2020.118616
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发表时间：
2020-05-15
影响因子：
22.1
通讯作者：
Majima, Tetsuro
中科院分区：
文献类型：
--
作者：
Shi, Xiaowei;Mao, Liang;Majima, Tetsuro
由于氢（H-2）演化反应（HER）的固有活性位点相对不足，以及光激发载流子的快速重组，无助催化剂的半导体光催化剂的活性仍远低于预期。本文首次从理论上和实验上证明了超薄六方结构ZnIn2S4 （ZIS）纳米片是一种很有前途的无共催化剂光催化剂。根据密度泛函理论（DFT）计算，与Zn和In原子配位的六方ZIS（110）面的S原子显示出H原子的理想吸附自由能(δ G（H)(0)）为-0.16 eV，可以作为HER的活性位点。因此，我们在柠檬酸三钠的帮助下制备了超薄ZIS纳米片（2.6-5.0 nm），暴露了更多（110）个面，以提供更多的活性位点。同时，通过飞秒瞬态吸收进行的光激发电子动力学研究表明，这种ZIS纳米片的平均衰变寿命更长（359 ps），这表明电荷分离效率提高。结果表明，在无助催化剂的情况下，超薄ZIS层在可见光（λ > 420 nm）照射下的HER（-1）达到1.94 mmol g(-1) h(-1)， 420 nm处的AQE为10.1%，是原始ZIS的11.2倍。该研究为结构活性关系研究带来了深刻的见解，并为开发用于H(2)演化的无助催化剂超薄二维光催化剂迈出了重要的一步。
Due to the relative insufficient intrinsic active sites for hydrogen (H-2) evolution reaction (HER) and fast recombination of photoexcited charge carriers, activity of semiconductor photocatalysts without cocatalyst is still far less than the expectations. Here, we for the first time theoretically and experimentally prove that ultrathin hexagonal structural ZnIn2S4 (ZIS) nanosheet is a promising cocatalystfree photocatalyst. According to density functional theory (DFT) calculations, the S atom on (110) facet of hexagonal ZIS coordinating with both Zn and In atoms shows an ideal adsorption free energy of H atom (Delta G(H)(0)) of -0.16 eV, which can act as active site for HER. Thus, we fabricate ultrathin ZIS nanosheets (2.6-5.0 nm) under the assistance of trisodium citrate with more (110) facets exposed to provide more active sites. Simultaneously photoexcited electron dynamics studied by femtosecond transient absorption reveals a longer average decay lifetime (359 ps) in such ZIS nanosheets, which indicates an enhanced charge separation efficiency. As a result, HER of the ultrathin ZIS layers in the absence of cocatalyst increases up to 1.94 mmol g(-1) h(-1) under visible light irradiation (lambda > 420 nm) with AQE at 420 nm of 10.1 %, which is 11.2 times larger than that of pristine ZIS. This work brings a deep insight into structuralactivity relationship study and takes a significant step toward the development of cocatalyst free ultrathin 2D photocatalysts for H(2 )evolution.