Photocatalytic CO2 Reduction Using a Pristine Cu2ZnSnS4 Film Electrode under Visible Light Irradiation
Photocatalytic CO2 Reduction Using a Pristine Cu2ZnSnS4 Film Electrode under Visible Light Irradiation
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在可见光照射下使用原始 Cu2ZnSnS4 薄膜电极光催化 CO2 还原
DOI：
10.1021/acs.jpcc.8b04241
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Miyauchi Masahiro
中科院分区：
文献类型：
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作者：
Yoshida Toshiki;Yamaguchi Akira;Umezawa Naoto;Miyauchi Masahiro
本研究在高纯CZTS膜电极的理论计算和实验评价的基础上，对金属硫化物Cu2ZnSnS4(CZTS)作为可见光活性光催化剂选择性还原CO2进行了全面的研究。在我们的第一性原理计算中，分别使用Heyd-Scus eria-Ernzerhof泛函和具有足够厚真空层的平板模型确定了准确的带隙数值，并讨论了其导带和价带的合适位置。因此，CZTS有望具有足够的高导带水平来驱动可见光照射下的CO2还原。我们用旋涂法制备了高纯度的CZTS薄膜，元素分析表明，该薄膜由接近化学计量比的CZTS组成。该膜电极在含有CO_2气泡的水介质中起到p型光电阴极的作用，在−为0.8V(vsAg/AgCl)的可见光照射下，即使在没有辅助催化剂修饰的情况下，它也能产生一氧化碳(CO)和氢气(H2)。根据我们用13CO2进行的同位素示踪实验，证实了产生的CO是起泡的CO2。此外，我们还证实了阳极侧的放氧，表明原始的CZTS可以利用水分子作为电子供体从CO2中生成CO。
The present study comprehensively investigated the metal sulfide Cu2ZnSnS4(CZTS) as a visible-light-active photocatalyst for selective CO2reduction on the basis of theoretical calculation and experimental evaluation of a highly pure CZTS film electrode. For our first-principles calculation, the Heyd–Scuseria–Ernzerhof functional and a slab model with a sufficiently thick vacuum layer for the crystal phase were used to determine the accurate band gap value and to discuss the proper positions of its conduction and valence bands, respectively. Consequently, CZTS could be expected to have sufficient high conduction band level to drive CO2reduction under visible light irradiation. We fabricated a highly pure CZTS thin film via spin-coating, and elemental analysis indicated that the film consisted of almost stoichiometric chemical composition of CZTS. Our pristine CZTS film electrode functioned as a p-type photocathode in aqueous media bubbled with CO2, and it could generate carbon monoxide (CO) in addition to hydrogen (H2) production under visible light irradiation with the application of bias at −0.8 V (vs Ag/AgCl) even without cocatalyst modification condition. According to our isotope trace experiment using13CO2, the origin of the produced CO was proved to be bubbled CO2. Furthermore, we confirmed oxygen evolution in the anodic side, indicating that pristine CZTS could produce CO from CO2using water molecules as electron donors.