Dirac Nodal Arc Semimetal PtSn₄: An Ideal Platform for Understanding Surface Properties and Catalysis for Hydrogen Evolution

Abstract

Conductivity, carrier mobility, and a suitable Gibbs free energy are important criteria that determine the performance of catalysts for a hydrogen evolution reaction (HER). However, it is a challenge to combine these factors into a single compound. Herein, we discover a superior electrocatalyst for a HER in the recently identified Dirac nodal arc semimetal PtSn4. The determined turnover frequency (TOF) for each active site of PtSn4 is 1.54 H2 s−1 at 100 mV. This sets a benchmark for HER catalysis on Pt‐based noble metals and earth‐abundant metal catalysts. We make use of the robust surface states of PtSn4 as their electrons can be transferred to the adsorbed hydrogen atoms in the catalytic process more efficiently. In addition, PtSn4 displays excellent chemical and electrochemical stabilities after long‐term exposure in air and long‐time HER stability tests.

Topological Engineering of Pt‐Group‐Metal‐Based Chiral Crystals toward High‐Efficiency Hydrogen Evolution Catalysts

“…The observation of the topological order in materials provides an extra reasonable solution for the design of high‐efficiency catalysts. To date, the introduction of the topological order is theoretically and experimentally demonstrated to be effective in tailoring adsorption and catalytic processes in the fields of hydrogen evolution, oxygen evolution, and CO oxidation, etc 14–20. The situation looks perfect!…”

“…Therefore, the chemical reaction of the catalytic process mainly occurs with Fermi arcs from the top four Pt atom layers. In addition, the large proportion of d orbitals in the surface states, rather than the s or p orbitals in the other topological catalysts,13,16,17 indicating a favorable interaction between the adsorbate and the catalysts surface based on the d‐band theory 15…”

Effect of magnetic field on the hydrogen evolution activity using non-magnetic Weyl semimetal catalysts

“…10,11 Topological materials, such as topological insulators, Weyl semimetals or nodal line semimetals, are robust against surface modifications and defects derived from dangling bonds, vacancies, or doping which otherwise destroy surface states. [12][13][14][15] Topological surface states (TSSs) are a result of the inversion of bulk bands, with the electron spin locked up with its momentum at the crystal surface in the presence of large spin-orbit coupling. Resultantly, backscattering is notably suppressed which otherwise dominates in materials that are constantly associated with surface defects to some extent.…”

“…16 Topological materials are therefore good candidates as catalysts because they possess high conductivity, topologically protected surface states, and suitable carrier concentration around the Fermi level. 12,13 Furthermore, owing to their rich and exotic physical properties, they provide a model platform to explore the interplay among surface states, electron transfer, and surface catalytic reactions. 12,17 It is now accepted that even an electron can act as a catalyst.…”

Topological Quantum Materials from the Viewpoint of Chemistry

“…In magnetic Weyl semimetals large anomalous Hall [30][31][32][33][34][35][36][37] , anomalous Nernst [38][39][40] and magneto optic effects 41 have been predicted or measured recently. Redox catalysis may also profit from topological properties 42 such as topological protected surface states [43][44][45] , chiral surface states 46 , giant electron mobilities 47,48 , despite insulating and semiconducting bulk electronic structures. In the second part of our review, we discuss several examples of giant responses in greater detail to stimulate further research by chemistry groups.…”