Department of Applied Physics and Astronomy, University of Sharjah, Sharjah 27272, United Arab Emirates Sharjah; Centre for Advanced Materials Research, Research Institute of Sciences and Engineering, University of Sharjah, Sharjah 27272, United Arab Emirates Sharjah; Laboratoire de Photovoltaïque, Centre de Recherches et des Technologies de l'Energie, Technopole de Borj-Cédria, Hammam-Lif 2050, Tunisia.
Department of Applied Physics and Astronomy, University of Sharjah, Sharjah 27272, United Arab Emirates Sharjah; Centre for Advanced Materials Research, Research Institute of Sciences and Engineering, University of Sharjah, Sharjah 27272, United Arab Emirates Sharjah.
J Environ Sci (China). 2021 Mar;101:123-134. doi: 10.1016/j.jes.2020.08.010. Epub 2020 Aug 25.
Homogeneous and vertically aligned silicon nanowires (SiNWs) were successfully fabricated using silver assisted chemical etching technique. The prepared samples were characterized using scanning electron microscopy, transmission electron microscopy and atomic force microscopy. Photocatalytic degradation properties of graphene oxide (GO) modified SiNWs have been investigated. We found that the SiNWs morphology depends on etching time and etchant composition. The SiNWs length could be tuned from 1 to 42 µm, respectively when varying the etching time from 5 to 30 min. The etchant concentration was found to accelerate the etching process; doubling the concentrations increases the length of the SiNWs by a factor of two for fixed etching time. Changes in bundle morphology were also studied as function of etching parameters. The SiNWs diameter was found to be independent of etching time or etchant composition while the size of the SiNWs bundle increases with increasing etching time and etchant concentration. The addition of GO was found to improve significantly the photocatalytic activity of SiNWs. A strong correlation between etching parameters and photocatalysis efficiency has been observed, mainly for SiNWs prepared at optimum etching time and etchant concentrations of 10 min and 4:1:8. A degradation of 92% was obtained which further improved to 96% by addition of hydrogen peroxide. Only degradation efficiency of 16% and 31% has been observed for bare Si and GO/bare Si samples respectively. The obtained results demonstrate that the developed SiNWs/GO composite exhibits excellent photocatalytic performance and could be used as potential platform for the degradation of organic pollutants.
采用银辅助化学刻蚀技术成功制备了均匀垂直排列的硅纳米线（SiNWs）。使用扫描电子显微镜、透射电子显微镜和原子力显微镜对制备的样品进行了表征。研究了氧化石墨烯（GO）修饰的 SiNWs 的光催化降解性能。我们发现，SiNWs 的形态取决于刻蚀时间和刻蚀剂组成。当刻蚀时间从 5 分钟变化到 30 分钟时，SiNWs 的长度可以分别从 1 µm 调节到 42 µm。发现刻蚀剂浓度会加速刻蚀过程；在固定的刻蚀时间下，将浓度加倍会使 SiNWs 的长度增加一倍。还研究了束状形态随刻蚀参数的变化。发现 SiNWs 的直径与刻蚀时间或刻蚀剂组成无关，而 SiNWs 束的尺寸随着刻蚀时间和刻蚀剂浓度的增加而增加。添加 GO 被发现显著提高了 SiNWs 的光催化活性。观察到刻蚀参数与光催化效率之间存在很强的相关性，主要是在最佳刻蚀时间和刻蚀剂浓度为 10 分钟和 4:1:8 的 SiNWs 中。降解率达到 92%，通过添加过氧化氢进一步提高到 96%。裸 Si 和 GO/裸 Si 样品的降解效率分别仅为 16%和 31%。所得结果表明，所开发的 SiNWs/GO 复合材料表现出优异的光催化性能，可作为降解有机污染物的潜在平台。
