Thermal responsive Rh<sub>1</sub>-Pd single-atom catalyst for controlling activity in direct formic acid fuel cells.

Su, Keying; Yang, Shan; Liang, Yujia; Sun, Dongmei; Gong, Mingxing; Tang, Yawen; Qiu, Xiaoyu · Nat Commun · 2025

basic_science · Level V

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Abstract

Single-atom catalysts are highly active for specific reactions; however, their sinter-resistance and clean surfaces make it difficult to impart them with a "smart" property. Herein we design a thermosensitive single-atom Rh<sub>1</sub>-Pd nanosheets (NSs) by employing amino functionalized poly(N-isopropylacrylamide) as thermal responsive gate for the "open"/"closed" control of electro-catalytic activity. Using formic acid electro-oxidation as model reaction, the thermosensitive Rh<sub>1</sub>-Pd NSs exhibit high mass activity (2.29 A mg<sub>PGM</sub><sup>-1</sup>), strong poisoning resistance, and reversible thermo-responsibility at a lower critical solution temperature (LCST) of 35 <sup>o</sup>C. In-situ spectroscopy and theoretical investigations reveal that the d-electron deficient Rh<sub>1</sub>-Pd NSs favor the direct formate pathway and weaken the binding of self-poisonous species, contributing to the high activity and anti-self-poisoning talent. Most importantly, for the direct formic acid fuel cells (DFAFCs), the thermosensitive Rh<sub>1</sub>-Pd NSs exhibit a high power density operated below the LCST, while the power drops sharply once above the LCST, realizing the intelligent battery thermal protection for DFAFCs.