Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, and Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou 510006, China.
Nanoscale. 2018 Feb 15;10(7):3518-3525. doi: 10.1039/c7nr09235k.
Silicon nanowires (SiNWs) are widely used as photocathodes because of their large electrochemically available surface-area density and inherent ability to decouple light absorption from the transport of minority carriers. In order to minimize overpotential for solar-driven hydrogen (H) production, a combination of an ultrathin molybdenum disulfide (MoS) layer with SiNWs as photocathode has attracted much attention. Herein, for the first time, this study presents the synthesis of a composite photocathode via direct growth of ultrathin MoS nanosheets on SiNWs (referred to as SiNWs/MoS) by one-step chemical vapor deposition (CVD). Due to the high surface-area density of the arrays of SiNWs, the discontinuous MoS nanosheets grown on the SiNWs achieved a much higher density of active sites. Moreover, the coating of MoS on the SiNWs was found to protect the photocathode during the photoelectrochemical (PEC) reaction. A high efficiency with photocurrent j of 16.5 mA cm (at 0 V vs. reversible hydrogen electrode) and an excellent stability over 48 h of PEC operation were achieved under a simulated 1 sun irradiation.
硅纳米线 (SiNWs) 由于其具有较大的电化学可用表面积密度和固有能力，可以将光吸收与少数载流子的输运分离，因此被广泛用作光电阴极。为了将太阳能驱动的制氢 (H) 反应的过电势最小化，将超薄二硫化钼 (MoS) 层与 SiNWs 结合作为光电阴极的组合受到了广泛关注。在此，本研究首次通过一步化学气相沉积 (CVD) 直接在 SiNWs 上生长超薄 MoS 纳米片来合成复合光电阴极 (简称 SiNWs/MoS)。由于 SiNWs 阵列具有高表面积密度，因此在 SiNWs 上生长的不连续 MoS 纳米片实现了更高密度的活性位点。此外，在光电化学 (PEC) 反应过程中，MoS 对 SiNWs 的涂层被发现可以保护光电阴极。在模拟的 1 个太阳光照射下，实现了 16.5 mA cm 的高光电流密度 j（相对于可逆氢电极的 0 V）和超过 48 小时的 PEC 运行稳定性。
