Expediting Hydrogen Evolution through Topological Surface States on Bi₂Te₃

Abstract

Recently, the development of efficient and non-noble metal electrocatalysts with good durability for the hydrogen evolution reaction (HER) has attracted increasing attention. The exotic and robust metallic surface states of topological insulators (TIs) are theoretically predicted to enhance surface catalytic activity of overlaying catalysts, but no experimental evidence for TIs directly used as electrocatalysts has ever been reported. In this work, we fabricated the TI thin films of Bi2Te3 with different thicknesses using the molecular beam epitaxy method, and found that these thin films exhibit high electrocatalytic activity in HER. The 48 nm Bi2Te3 thin film has the best performance, which is attributed to its largest active area arising from the spiral growth mode of triangular domains as revealed by atomic force microscopy imaging. Importantly, our theoretical calculations reveal that while pure Bi2Te3 is not a good electrocatalyst, the Bi2Te3 thin films with partially oxidized surfaces or Te vacancies have high HER activity. The existence of the corresponding surface oxides on the Bi2Te3 thin films is supported by our X-ray photoelectron spectroscopy data. We have also made a direct comparison between a Bi2Te3 and a Bi2Te3:Fe thin film on their magneto-transport properties and HER performances. Particularly, this work demonstrates that the topological surface states play a key role in enhancing the HER performance. Our study offers a direction to design cost-effective electrocatalysts.

Few‐Layer Tellurium: Cathodic Exfoliation and Doping for Collaborative Hydrogen Evolution

“…As the overpotential increases, Te 0 species are reduced to Te 2 2− species, which enables them to adsorb protons via electrostatic interaction to form H + –Te 2 2− . Similar to previous observations in metal (di)telluride, [ 30 ] the H + –Te–Pt–H ad local structure facilitates the Heyrovsky step, outperforming the HER catalyzed by Pt poly . After the discharge of H 2 atoms from the Pt sites, the surrounding H + –Te sites can provide H + for a rapid reduction on Pt.…”

“…This Volmer–Heyrovsky mechanism is consistent with previous findings for metal (di)tellurides, such as Bi 2 Te 3 , CoTe 2 , and NiTe 2 . [ 24,30 ] Further stability test (Figure 5d) proves the strong interaction between Pt sites and the Te NS substrates under reaction conditions, where a stable current density of 28.9 mA cm −2 is maintained for 2 h (η = 250 mV). Inductively coupled plasma atomic emission spectroscopy suggests an overall 0.75 at% Pt after the 2‐hour reaction, indicating a Pt loss of 4.4%.…”

Role of topological surface states and mirror symmetry in topological crystalline insulator SnTe as an efficient electrocatalyst

“…Our previous study reveals that light doping of Fe in Bi 2 Te 3 can destroy the TSSs of Bi 2 Te 3 as supported by the quenching of the weak antilocalization (WAL) signature. 5 The growth of the top SnTe (111) layer was then followed to complete the growth of this sample.…”

“…222) in this broad-scan profile due to the very small lattice mismatch (0.27%) between ZnSe and GaAs. 5,14,15 Fig. 1b displays the HRXRD profile of the SnTe (001) sample.…”

“…Recently, studies on a number of topological materials were reported both experimentally and theoretically to provide a novel direction for the design of high-efficiency non-noblemetal catalysts for the hydrogen evolution reaction (HER). [1][2][3][4][5] It has been well accepted that the highly desirable functionality in topological insulator (TI)-based HER electrocatalysts is attributed to the topological surface states (TSSs) as revealed by first-principles density functional theory (DFT) calculations. 4,6,7 In the past few years, several bismuth chalcogenide-based TIs have been proved to be promising candidates of photocatalysts, 2 and Bi 2 Te 3 thin films with partially oxidized structures or Te vacancies 5 were shown to display high HER activities, providing evidence of the important role of TSSs in catalytic processes.…”