High Electrocatalytic Response of Ultra-refractory Ternary Alloys of Ta-Hf-C Carbide toward Hydrogen Evolution Reaction in Acidic Media

Abstract

Transition metal carbide alloys are promising materials to replace platinum as electrodes in electrocatalysts toward the hydrogen evolution reaction (HER). Although tantalum hafnium carbides (Ta-Hf-C) have shown outstanding refractory and structural properties, there is no clear role of their electrochemical efficiency. Here we report on the electrochemical activity of such thin films, (Ta 2 C) (100−x)% •(Hf 2 C) (x)% , x = 100, 70, 30, and 0, deposited by magnetron sputtering. Grazing incidence X-ray diffraction showed no evidence of phase segregation, and XPS confirms the well-controlled stoichiometry of the electrodes. The HER kinetics was studied in strong acidic conditions, and it was found that the (Ta 2 C) 70% •(Hf 2 C) 30% was the most active material toward HER in this acid media and displayed an onset overpotential of −198 mV vs NHE and a Tafel slope of 129 mV•dec −1 . Our results suggest that the strong affinity of Hf-C toward oxygen reduction reaction could be responsible for the high catalytic response and strong oxidation resistance of the ternary carbide alloys. Finally, we show that, in fact, the Ta-Hf-C alloys can be competitive materials toward HER.

Structural stability, hardness, fracture toughness and melting points of Ta1-xHfxC and Ta1-xZrxC ceramics from first-principles

“…x Hf x C and Ta 1 − x Zr x C systems are consistent with experimental and other DFT calculated results [18,40,67]. Furthermore, the Vickers Hardness (H V ) of Ta 1 − x Hf x C solid solution ceramics exhibited crest and trough shape with increasing Hf content, which is consistent with the available experimental Vickers hardness (H V ) [68,69]. In particular, it can be found that Ta 0.8 Hf 0.2 C has the highest Vickers hardness (H V ).…”

Atomic layer deposition of Pd nanoparticles on self-supported carbon-Ni/NiO-Pd nanofiber electrodes for electrochemical hydrogen and oxygen evolution reactions

“…CNMs can promote the electron transfer reaction kinetics, enhance electrocatalyst activity, and minimize electrode surface fouling. Recently, CNMs have been used to improve the electrocatalytic activity and enhance the chemical stability of transition-metal nanoparticles (NPs) for electrochemical water splitting [18,19]. Indeed, the encapsulation of transition-metal NPs with carbon paste [20,21], carbon nanotubes [22], carbon nanofibers (CNFs) [23], or graphene [24,25], significantly enhances their chemical stability and leads to higher electrochemical activity for OER, HER, and oxygen reduction reactions [26][27][28].…”

Simultaneous hydrogen and oxygen evolution reactions using free-standing nitrogen-doped-carbon–Co/CoOx nanofiber electrodes decorated with palladium nanoparticles

“…14,15,16 Transition metal/metal oxide NPs incorporated in CNFs also show superior electrocatalytic activity, stability, and selectivity in HER/OER. 36,37 Other cheap and effective electrode materials for HER/OER include transition metal carbides, 38 perovskites (ABO3 in which A and/or B are transition metals), and oxide spinel (AB2O4 in which A and/or B are transition metals).…”