Ultrathin Alumina Passivation for Improved Photoelectrochemical Water Oxidation Catalysis of Tin Oxide Sensitized by a Phosphonate-Functionalized Perylene Diimide First Without, and Then With, CoOy
Ultrathin Alumina Passivation for Improved Photoelectrochemical Water Oxidation Catalysis of Tin Oxide Sensitized by a Phosphonate-Functionalized Perylene Diimide First Without, and Then With, CoOy
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超薄氧化铝钝化用于改进氧化锡的光电化学水氧化催化，先由磷酸盐官能化苝二酰亚胺敏化，先不含 CoOy，然后再添加 CoOy
DOI：
10.1039/d1se00908g
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Finke, R. G.
中科院分区：
文献类型：
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作者：
Jewell, C. F.;Subramanian, A.;Finke, R. G.
先前，由涂覆有二萘嵌苯二酰亚胺染料N，N ′-双（膦酰基甲基）-3，4，9，10-二萘嵌苯二酰亚胺（PMPDI）的纳米结构的SnO2加上光电化学沉积的氧化钴（CoOy）组成的光电阳极显示出以31 ± 7%的法拉第效率光电化学氧化水。该现有系统的非理想部分在于，由于电荷-载流子复合的增加，已知的CoOy水氧化催化剂（WOC）的添加导致总光电流的减少而不是预期的增加。在此，我们表明通过原子层沉积（ALD）在SnO2/PMPDI光阳极上施加的氧化铝覆盖层的沉积可以提高系统的光活性和催化活性;添加ca. 1nm厚的AlOx层沉积在4000nm（即，4微米）厚的中孔阳极系统可以并且确实通过减少电荷-载流子复合而在稳态光电流方面具有29 ± 9%法拉第效率，与没有氧化铝钝化的对照阳极相比具有2.5倍的正改善。此外，ALD沉积的AlOx层确实有助于支持对在SnO2/PMPDI DS-PEC上共沉积CoOy WOC的"反催化"的理解-特别是直接CoOy-SnO2接触介导的复合的图片-但是AlOx层不能改善净SnO2/PMPDI/AlOx（/CoOy）系统中的光电流。我们归因于CoOy WOC的性能增强的缺乏，每个SnO2纳米粒子的AlOx的不完全覆盖。总的来说，我们发现添加优化的SnO2/AlOx层（0.6 nm厚;在85 ° C下沉积）将SnO2/PMPDI/AlOx系统的光活性提高了高达约1倍。3-减少重组。这些结果证明，通过低温ALD的金属氧化物钝化可以是用于改善甚至纳米结构的染料敏化光电化学电池的水氧化性能的有效策略。
Previously, a photoanode composed of nanostructured SnO2 coated with the perylene diimide dye N,N′-bis(phosphonomethyl)-3,4,9,10-perylenediimide (PMPDI) plus photoelectrochemically deposited cobalt oxide (CoOy) was shown to photoelectrochemically oxidize water at 31 ± 7% faradaic efficiency. A non-ideal part of that prior system is that the addition of the known CoOy water oxidation catalyst (WOC) resulted in a reduction of the total photocurrent rather than the anticipated increase, due to an increase in charge-carrier recombination. Herein, we show deposition of an ultrathin alumina overlayer applied by atomic layer deposition (ALD) on the SnO2/PMPDI photoanode can improve the photoactivity and catalytic activity of the system; the addition a ca. 1 nm-thick AlOx layer deposited on a 4000 nm (i.e., 4 micron) thick mesoporous anode system can and does have a positive, 2.5-fold improvement in the steady-state photocurrent with 29 ± 9% faradaic efficiency vs. the control anode without alumina passivation by reducing charge-carrier recombination. Moreover, ALD-deposited AlOx layer does help support the understanding of the “anti-catalysis” of co-depositing a CoOy WOC on the SnO2/PMPDI DS-PECs—specifically the picture of direct CoOy–SnO2 contact-mediated recombination—but that AlOx layer was unable to improve the photocurrent in a net SnO2/PMPDI/AlOx(/CoOy) system. We attribute the lack of a performance enhancement by CoOy WOC to incomplete coverage of each SnO2 nanoparticle by the AlOx. Overall, we find the addition of an optimized ultrathin AlOx layer (0.6 nm thick; deposited at 85 °C) improves the SnO2/PMPDI/AlOx system's photoactivity by a factor of up to ca. 3-fold with reduced recombination. These results document that metal-oxide passivation by low-temperature ALD can be an effective strategy for improving the water oxidation performance of even nanostructured dye sensitized-photoelectrochemical cell.