Search Results
Engineering grain boundaries at the 2D limit for the hydrogen evolution reaction
2020, He, Yongmin, Tang, Pengyi, Hu, Zhili, He, Qiyuan, Zhu, Chao, Wang, Luqing, Zeng, Qingsheng, Golani, Prafful, Gao, Guanhui, Fu, Wei, Huang, Zhiqi, Gao, Caitian, Xia, Juan, Wang, Xingli, Wang, Xuewen, Zhu, Chao, Ramasse, Quentin M., Zhang, Ao, An, Boxing, Zhang, Yongzhe, Martí-Sánchez, Sara, Morante, Joan Ramon, Wang, Liang, Tay, Beng Kang, Yakobson, Boris I., Trampert, Achim, Zhang, Hua, Wu, Minghong, Wang, Qi Jie, Arbiol, Jordi, Liu, Zheng
Atom-thin transition metal dichalcogenides (TMDs) have emerged as fascinating materials and key structures for electrocatalysis. So far, their edges, dopant heteroatoms and defects have been intensively explored as active sites for the hydrogen evolution reaction (HER) to split water. However, grain boundaries (GBs), a key type of defects in TMDs, have been overlooked due to their low density and large structural variations. Here, we demonstrate the synthesis of wafer-size atom-thin TMD films with an ultra-high-density of GBs, up to ~1012 cm−2. We propose a climb and drive 0D/2D interaction to explain the underlying growth mechanism. The electrocatalytic activity of the nanograin film is comprehensively examined by micro-electrochemical measurements, showing an excellent hydrogen-evolution performance (onset potential: −25 mV and Tafel slope: 54 mV dec−1), thus indicating an intrinsically high activation of the TMD GBs.
Self-cross-linked arrays enabled flexible mechanical sensors for monitoring the body tremor
2020, Wang, Xuewen, Fu, Wei, Gao, Guanhui, Mehay, Mandeep Singh, Wang, Hong, Zhao, Wu, Loh, Kian Ping, Zhang, Ting, Huang, Wei, Liu, Zheng
Thin-film electronics played an important role in flexible healthcare sensor applications. The common status of their constituent blocks are solid film and network structures. However, the solid film could only sustain bend in a narrow range due to cracks, and the network structure decreased the sensitivity of flexion sensors due to the strong interactions between nanowires. New materials and technologies are urgently required for flexible sensing electronics, to produce the reliable data for assessment of the human body. Here, we report on a novel three-dimensional (3D) carbon nanorods array (CNA) that is characterized as vertically aligned nanorods and self-cross-linked junctions. We also demonstrate the CNA-based flexible healthcare sensors in monitoring the Parkinsonian tremors. Comparing with two-dimensional (2D) carbon nanotube networks and solid thin films, such self-cross-linked geometries are highly resistant to crack and fragmentation under strain. In the meantime, it shows high sensitivity and good stability (~10,000 times) to detect the flexions. These CNA-based flexible devices are capable of recording low-frequency vibrations (<6 Hz) and make it excellent to monitor the rest tremor of the human body, which is an initial symptom of Parkinson’s disease. The 3D self-cross-linked CNA film shows great potential in the fabrication of cost-effective and durable flexible sensors for early diagnosis of disease by monitoring the health-related rest tremors. © 2020, The Author(s).