ZnO Nanosheets Decorated with Graphite-Like Carbon Nitride Quantum Dots as Photoanodes in Photoelectrochemical Water Splitting
ZnO Nanosheets Decorated with Graphite-Like Carbon Nitride Quantum Dots as Photoanodes in Photoelectrochemical Water Splitting
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DOI：
10.1021/acsanm.0c00081
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发表时间：
2020-02-01
影响因子：
5.9
通讯作者：
Basu, Mrinmoyee
中科院分区：
文献类型：
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作者：
Mahala, Chavi;Sharma, Mamta Devi;Basu, Mrinmoyee
高效利用太阳能正成为将其转化为可储存、清洁和可再生能源的重要策略。为了从太阳能中产生作为化学燃料的H-2，正在尝试建立光电化学（PEC）水分解作为一种有效的、更绿色的途径。在这里，ZnO 2D纳米片的表面由石墨状氮化碳（g-C3 N4）量子点（QD）装饰，旨在开发高效的光阳极。C3 N4量子点对ZnO纳米片的敏化作用使其光电转换性能比裸ZnO的光电转换性能更强。在PEC中观察到的增强是由于高光吸收和光子产生的电荷载流子分离。最佳获得的ZnO/C3 N4光阳极表现出近2.29倍的高光电流密度相比，裸ZnO。ZnO二维片在0.5994 V对可逆氢电极（RHE）下可以产生0.414 mA cm（-2）的光电流密度，而ZnO/C3 N4在0.5994 V对RHE下可以产生0.952 mA cm（-2）的光电流密度。此外，由于载流子密度的增强，观察到的异质结构的PEC活性得到改善。与裸ZnO片相比，异质结构中的载流子密度提高了近2.2倍。ZnO/C3 N4的最大光电转换效率（eta）为0.70%。ZnO二维片和ZnO/C3 N4异质结构在短时间光照射1000 s下表现出有效的稳定性。ZnO/C3 N4的稳定性也在连续光照下测定了1小时。
The efficient utilization of solar power is becoming an important strategy for its conversion into a storable, clean, and renewable energy source like H-2. To generate H-2 as a chemical fuel from solar power, attempts are being made to establish photoelectrochemical (PEC) water splitting as an efficient, greener pathway. Here, the surfaces of ZnO 2D nanosheets are adorned by graphite-like carbon nitride (g-C3N4) quantum dots (QDs) with the intention of developing efficient photoanodes. Sensitization of ZnO nanosheets with C3N4 QDs leads to a more enhanced PEC performance than that of bare ZnO. The observed enhancement in PEC is due to the high light absorbance and photon-generated charge-carrier separation. The best-obtained ZnO/C3N4 photo anode exhibits a nearly 2.29 times as high photocurrent density compared to bare ZnO. ZnO 2D sheets can generate a photocurrent density of 0.414 mA cm(-2) at 0.5994 V versus reversible hydrogen electrode (RHE), whereas ZnO/C3N4 can produce 0.952 mA cm(-2) at 0.5994 V versus RHE under uninterrupted conditions of light illumination. Further, there is improvement in the observed PEC activity of the heterostructure because of enhancement in the carrier density. The carrier density enhances nearly 2.2 times in the heterostructure compared to the bare ZnO sheet. ZnO/C3N4 shows a maximum photoconversion efficiency (eta) of 0.70%. Both ZnO 2D sheets and the ZnO/C3N4 heterostructure show efficient stability under chopped irradiation of light for 1000 s. The stability of ZnO/C3N4 is also determined for 1 h under continuous illumination.