Sang Lixia, Lei Lei, Burda Clemens
Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education and Key Laboratory of Heat Transfer and Energy Conversion, Beijing Municipality, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing, 100124, People's Republic of China.
Department of Chemistry, Center for Chemical Dynamics and Nanomaterials Research, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
Nanomicro Lett. 2019 Nov 7;11(1):97. doi: 10.1007/s40820-019-0329-2.
Effective utilization of hot electrons generated from the decay of surface plasmon resonance in metal nanoparticles is conductive to improve solar water splitting efficiency. Herein, Ag nanoparticles and reduced graphene oxide (rGO) co-decorated hierarchical TiO nanoring/nanotube arrays (TiO R/T) were facilely fabricated by using two-step electrochemical anodization, electrodeposition, and photoreduction methods. Comparative studies were conducted to elucidate the effects of rGO and Ag on the morphology, photoresponse, charge transfer, and photoelectric properties of TiO. Firstly, scanning electron microscope images confirm that the Ag nanoparticles adhered on TiO R/T and TiO R/T-rGO have similar diameter of 20 nm except for TiO R-rGO/T. Then, the UV-Vis DRS and scatter spectra reveal that the optical property of the Ag-TiO R/T-rGO ternary composite is enhanced, ascribing to the visible light absorption of plasmonic Ag nanoparticles and the weakening effect of rGO on light scattering. Meanwhile, intensity-modulated photocurrent spectroscopy and photoluminescence spectra demonstrate that rGO can promote the hot electrons transfer from Ag nanoparticles to Ti substrate, reducing the photogenerated electron-hole recombination. Finally, Ag-TiO R/T-rGO photoanode exhibits high photocurrent density (0.98 mA cm) and photovoltage (0.90 V), and the stable H evolution rate of 413 μL h cm within 1.5 h under AM 1.5 which exceeds by 1.30 times than that of pristine TiO R/T. In line with the above results, this work provides a reliable route synergizing rGO with plasmonic metal nanoparticles for photocatalysis, in which, rGO presents a broad absorption spectrum and effective photogenerated electrons transfer.
有效利用金属纳米颗粒表面等离子体共振衰减产生的热电子有助于提高太阳能水分解效率。在此，通过两步电化学阳极氧化、电沉积和光还原方法，轻松制备了银纳米颗粒和还原氧化石墨烯（rGO）共修饰的分级TiO纳米环/纳米管阵列（TiO R/T）。进行了对比研究以阐明rGO和Ag对TiO的形貌、光响应、电荷转移和光电性能的影响。首先，扫描电子显微镜图像证实，除了TiO R-rGO/T外，附着在TiO R/T和TiO R/T-rGO上的银纳米颗粒直径相似，均为20nm。然后，紫外-可见漫反射光谱和散射光谱表明，Ag-TiO R/T-rGO三元复合材料的光学性能得到增强，这归因于等离子体银纳米颗粒的可见光吸收以及rGO对光散射的减弱作用。同时，强度调制光电流光谱和光致发光光谱表明，rGO可以促进热电子从银纳米颗粒转移到Ti基底，减少光生电子-空穴复合。最后，Ag-TiO R/T-rGO光阳极表现出高光电流密度（0.98 mA cm）和光电压（0.90 V），在AM 1.5条件下1.5小时内稳定的析氢速率为413 μL h cm，比原始TiO R/T高出1.30倍。与上述结果一致，这项工作提供了一条将rGO与等离子体金属纳米颗粒协同用于光催化的可靠途径，其中，rGO具有宽吸收光谱和有效的光生电子转移。
