Pt Atomic Chain: Local Asymmetry One-Dimensional Array for Enhanced Electrochemical Reactions

Atomically dispersed arrays enhance the intrinsic catalysis activity of isolated atoms by synergistic effects. However, uneven charge distribution limits the formation of local asymmetric structures within the array, making it difficult to break the linear proportional relationship in complex multi-intermediate chemical reactions. Here, by creating ordered in-plane vacancies in the Mo_1.33C surface to induce a looser lattice skeleton and then promoting the in situ substitution of Mo by Pt atoms, we report a locally asymmetric 1D sawtooth-shaped Pt atomic chain (Pt AC). The bridging sites within this asymmetric structure reduce the energy barriers for hydrolysis and intermediate adsorption, allowing Pt AC to show superior hydrogen evolution reaction (HER) activity (12.52 A mg_Pt ^-1) than isolated Pt single atoms (Pt SA, 1.32 A mg_Pt ^-1) and commercial Pt/C (0.18 A mg_Pt ^-1). In addition, the three-fold hollow sites in the asymmetric structure are prone to adsorb and oxidize dopamine (DA), which is key to triggering the high sensing performance of Pt AC. Pt AC has much higher sensitivity (0.1-1 µm: 19.5 µA µM^-1 and 1-100 µm: 1.6 µA µM^-1) compared to Pt SA. This work opens a door for the development of atomically dispersed arrays with asymmetric structures for surface chemistry applications.