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 MoS2 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/nm2, 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.