Department of Chemistry, University of California , Berkeley, California 94720, United States.
Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States.
Nano Lett. 2016 Sep 14;16(9):5675-80. doi: 10.1021/acs.nanolett.6b02321. Epub 2016 Aug 5.
Reducing carbon dioxide with a multicomponent artificial photosynthetic system, closely mimicking nature, represents a promising approach for energy storage. Previous works have focused on exploiting light-harvesting semiconductor nanowires (NW) for photoelectrochemical water splitting. With the newly developed CO2 reduction nanoparticle (NP) catalysts, direct interfacing of these nanocatalysts with NW light absorbers for photoelectrochemical reduction of CO2 becomes feasible. Here, we demonstrate a directed assembly of NP catalysts on vertical NW substrates for CO2-to-CO conversion under illumination. Guided by the one-dimensional geometry, well-dispersed assembly of Au3Cu NPs on the surface of Si NW arrays was achieved with facile coverage tunability. Such Au3Cu NP decorated Si NW arrays can readily serve as effective CO2 reduction photoelectrodes, exhibiting high CO2-to-CO selectivity close to 80% at -0.20 V vs RHE with suppressed hydrogen evolution. A reduction of 120 mV overpotential compared to the planar (PL) counterpart was observed resulting from the optimized spatial arrangement of NP catalysts on the high surface area NW arrays. In addition, this system showed consistent photoelectrochemical CO2 reduction capability up to 18 h. This simple photoelectrode assembly process will lead to further progress in artificial photosynthesis, by allowing the combination of developments in each subfield to create an efficient light-driven system generating carbon-based fuels.
利用类似于自然的多组分人工光合作用系统来减少二氧化碳，代表了一种有前途的储能方法。以前的工作主要集中在利用光收集半导体纳米线（NW）进行光电化学水分解。随着新型 CO2 还原纳米颗粒（NP）催化剂的开发，这些纳米催化剂与 NW 光吸收体的直接界面对于 CO2 的光电化学还原变得可行。在这里，我们展示了在光照下将 NP 催化剂定向组装到垂直 NW 基底上以进行 CO2 到 CO 的转化。在一维几何的引导下，实现了 Au3Cu NPs 在 Si NW 阵列表面上的良好分散组装，具有易于控制的覆盖率。这种 Au3Cu NP 修饰的 Si NW 阵列可以很容易地用作有效的 CO2 还原光电电极，在 -0.20 V 相对于 RHE 的情况下表现出接近 80%的高 CO2 到 CO 的选择性，同时抑制了氢气的产生。与平面（PL）相比，观察到 120 mV 的过电位降低，这是由于 NP 催化剂在高表面积 NW 阵列上的优化空间排列所致。此外，该系统在 18 小时内表现出一致的光电化学 CO2 还原能力。这种简单的光电电极组装工艺将通过允许每个子领域的发展相结合来创造一个高效的光驱动系统，从而产生基于碳的燃料，从而在人工光合作用方面取得进一步进展。
