Pt-O bond as an active site superior to Pt<sup>0</sup> in hydrogen evolution reaction.

Yu, Fei-Yang; Lang, Zhong-Ling; Yin, Li-Ying; Feng, Kun; Xia, Yu-Jian; Tan, Hua-Qiao; Zhu, Hao-Tian; Zhong, Jun et al. · Nat Commun · 2020

basic_science · Level V

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Abstract

The oxidized platinum (Pt) can exhibit better electrocatalytic activity than metallic Pt<sup>0</sup> in the hydrogen evolution reaction (HER), which has aroused great interest in exploring the role of oxygen in Pt-based catalysts. Herein, we select two structurally well-defined polyoxometalates Na<sub>5</sub>[H<sub>3</sub>Pt<sup>(IV)</sup>W<sub>6</sub>O<sub>24</sub>] (PtW<sub>6</sub>O<sub>24</sub>) and Na<sub>3</sub>K<sub>5</sub>[Pt<sup>(II)</sup><sub>2</sub>(W<sub>5</sub>O<sub>18</sub>)<sub>2</sub>] (Pt<sub>2</sub>(W<sub>5</sub>O<sub>18</sub>)<sub>2</sub>) as the platinum oxide model to investigate the HER performance. Electrocatalytic experiments show the mass activities of PtW<sub>6</sub>O<sub>24</sub>/C and Pt<sub>2</sub>(W<sub>5</sub>O<sub>18</sub>)<sub>2</sub>/C are 20.175 A mg<sup>-1</sup> and 10.976 A mg<sup>-1</sup> at 77 mV, respectively, which are better than that of commercial 20% Pt/C (0.398 A mg<sup>-1</sup>). The in situ synchrotron radiation experiments and DFT calculations suggest that the elongated Pt-O bond acts as the active site during the HER process, which can accelerate the coupling of proton and electron and the rapid release of H<sub>2</sub>. This work complements the knowledge boundary of Pt-based electrocatalytic HER, and suggests another way to update the state-of-the-art electrocatalyst.