Potassium-Promoted Formic Acid Dehydrogenation on Cu(111): Visualizing HCOO–‑K+ Intermediates - Jing Xie; Yi Zeng; Ziqi Sun; Jiawang Liu; Chen Zhang; Yue Wang; Wenyu Sun; Jiahui Wang; Duanyun Cao; Qing Guo; Jing Guo (JACS Au)