Mitrofanovite, Layered Platinum Telluride, for Active Hydrogen Evolution

Abstract

Two-dimensional (2D) layered catalysts have been considered as a class of ideal catalysts for hydrogen evolution reaction (HER) because of their abundant active sites with almost zero Gibbs energy change for hydrogen adsorption. Despite the promising performance, the design of stable and economic electrochemical catalyst based on 2D materials remains to be resolved for industrial-scale hydrogen production. Here, we report layered platinum tellurides, mitrofanovite Pt3Te4, which serves as an efficient and stable catalyst for HER with an overpotential of 39.6 mV and a Tafel slope of 32.7 mV/dec together with a high current density exceeding 7000 mA/cm2. Pt3Te4 was synthesized as nanocrystals on a metallic molybdenum ditelluride (MoTe2) template by a rapid electrochemical method. X-ray diffraction and high-resolution transmission microscopy revealed that the Pt3Te4 nanocrystals have a unique layered structure with repeated monolayer units of PtTe and PtTe2. Theoretical calculations exhibit that Pt3Te4 with numerous edges shows near-zero Gibbs free-energy change of hydrogen adsorption, which shows the excellent HER performance as well as the extremely large exchange current density for massive hydrogen production.

Unveiling the Mechanisms Ruling the Efficient Hydrogen Evolution Reaction with Mitrofanovite Pt3Te4

“…When the current density reaches 10 mA cm –2 , the HER overpotentials for Pt 3 T 4 is only 46 mV, which is very close to than that of Pt electrode. A similar value was also reported for Pt 3 Te 4 nanocrystals, 28 in spite of the reduced surface-to-volume ratio in bulk compared to nanocrystals in ref ( 28 ). Moreover, all the Pt 3 T 4 samples (both pristine one and those ones modified by electrochemical treatments) show almost identical catalytic behavior at the low overpotential region.…”

“… 27 Very recently, Bae et al have reported the synthesis of mitrofanovite Pt 3 Te 4 nanocrystals on a metallic molybdenum ditelluride (MoTe 2 ) template by an electrochemical method, which shows good HER performance. 28 However, the relationship between the HER activity and the physicochemical properties of Pt 3 Te 4 remains ambiguous, also considering the improper analysis of electronic band structure, with subsequent misleading theoretical model (see Section S16 in the Supporting Information for more details). Furthermore, such synthesis procedure is unsuitable for large-scale production and fails in reproducibility, due to its complexity.…”

Efficient Hydrogen Evolution Reaction with Bulk and Nanostructured Mitrofanovite Pt3Te4

“…Moreover, the Te termination evolved into a nanometric oxide layer, whose thickness was estimated by quantitative XPS. Conversely, in the case of the Pt 3 Te 4 -nanocrystal, tellurium–oxide was always present [ 20 ].…”

“…Additionally, from the inspection of Figure 6 b it is evident that the Tafel slope of Pt 3 Te 4 decreases with the dimensionality. In fact, in the case of Pt 3 Te 4 nanocrystals, the reported Tafel slope was 33 mV/dec and the reported current density was as high as 7000 mA/cm 2 , which should be attributed to the formation of numerous edges and defects in the growth process and the consequent near-zero Gibbs free-energy change of hydrogen adsorption [ 20 ].…”

“…In particular, mitrofanovite is a recently discovered mineral [ 17 ], which was demonstrated to be a topological metal with spin-polarized surface states, with subsequent capabilities for applications in spintronics [ 18 ]. Nevertheless, recent findings from different groups highlight the huge potential of mitrofanovite for hydrogen production [ 19 , 20 ]. In this Feature Article, the main features of electrocatalysis with mitrofanovite are discussed, with a particular focus on the effects of dimensionality on the catalytic performances.…”