The Weyl Semimetals M IrTe 4 (M = Nb, Ta) as Efficient Catalysts for Dye‐Sensitized Hydrogen Evolution

The prevalent global energy crisis calls for searching viable pathways for generating green hydrogen as an alternative energy resource. Dye‐sensitized photocatalytic water splitting is a feasible solution to produce green hydrogen. However, identifying suitable catalysts has been one of the bottlenecks in driving dye‐sensitized photocatalysis efficiently. In this work, a new class of electrocatalysts is reported based on the layered Weyl semimetals M IrTe 4 (M = Nb, Ta) for the Eosin Y (EY)‐sensitized hydrogen evolution reaction (HER). NbIrTe 4 and TaIrTe 4 exhibit HER activities of ≈18 000 and 14 000 µmol g −1 respectively, after 10 h of irradiation with visible light. Time‐dependent UV‐Vis spectroscopy and high‐pressure liquid chromatography coupled with mass spectrometry analysis shed light on the reaction dynamics and enable a deeper understanding of the observed trend in hydrogen evolution rates for M IrTe 4 . M IrTe 4 semimetals outperform transition metal‐based Weyl semimetals in terms of catalytic HER activity using EY as photosensitizer and triethanolamine as the sacrificial agent. It is hypothesized that the topology‐related band inversion in M IrTe 4 Weyl semimetals promotes a high density of M d‐states near the Fermi level, driving their high catalytic performance. This study introduces a new class of layered Weyl semimetals as efficient catalysts, and provides perspectives for designing topology‐enhanced catalysts.