Chain-ordered Pt atoms with delocalized electronic structure for improved hydrogen production

As the smallest one-dimensional structure, single-atom chains exhibit many one-dimensional quantized behaviors, such as Tomonaga-Luttinger liquid behavior, high-temperature superconductivity, and fluctuations. In contrast to single-atom catalysts, there is growing interest in exploring whether and how the point-to-point interaction occurs between neighboring metal atoms in 1D chains. Here, we controllably fabricate Pt chains and single atoms in MoS 2 films with similar coordination environments and conduct model studies on their catalytic behaviors in hydrogen production. Combining calculations with field effect transistor and micro-electrochemical measurements, we reveal that the chains exhibit significant delocalized electron densities, which underpins their metallic behavior and engenders a fascinating center site with lower Gibbs free energy than that of single atoms. Notably, we demonstrate that the chain density can be well-tuned, achieving a maximum of 2.82 Pt/nm 2 , which enables a competitive turnover frequency and wafer-scale hydrogen production. This work offers insights into our understanding of the possible synergistic effect between metal atoms in a 1D arrangement for electrocatalysis. Controlling single atoms into one-dimensional chains offers a platform to study atomic interactions. Here, the authors report that Pt chains host delocalized electrons and a distinct active site, giving metallic character and faster hydrogen evolution than isolated atoms.