Klingenhof, M.; Trzesniowski, H.; Koch, S.; Zhu, J.; Zeng, Z.; Metzler, L.; Klinger, A.; Elshamy, M.; Lehmann, F.; Buchheister, P.W.; Weisser, A.; Schmid, G.; Vierrath, S.; Dionigi, F.; Strasser, P.: High-performance anion-exchange membrane water electrolysers using NiX (X = Fe,Co,Mn) catalyst-coated membranes with redox-active Ni-O ligands. Nature Catalysis 7 (2024), p. 1213-1222
10.1038/s41929-024-01238-w
Abstract:
Recent efforts in anion-exchange membrane water electrolysis (AEMWE) focus on developing superior catalysts and membrane electrode assemblies to narrow the performance gaps compared with proton-exchange membrane water electrolysis (PEMWE). Here we present and characterize Ir-free AEMWE cells with NiX (X = Fe, Co or Mn) layered double hydroxide (LDH) catalyst-coated membranes with polarization characteristics and hydrogen productivities approaching those of acidic PEMWE cells, achieving >5 A cm−2 at <2.2 V. Operando spectroscopy revealed a correlation between Ni4+ centres and redox-active O ligands with an O K-edge feature, attributed to µ3-O ligands in the γ-LDH catalytic phase via density functional theory calculations. This computational–experimental study challenges the previously assumed correlation between spectral O K-edge features and oxygen evolution reaction performance in Ni-based LDH catalysts and provides insights from the molecular to the technological level demonstrating how redox-active Ni–O species and innovative catalyst-coated membrane preparation boost AEMWE performance to values rivalling state-of-the-art PEMWE cell technology.