![]() investigated the electrochemically active iridium nanoparticles for OER in acidic conditions and revealed that the catalytic activity is from the formation of shared electron-holes in the O 2p and Ir 5d, which leads to the generation of electron-deficient oxygen species 30. For instance, using in situ and ex situ x-ray spectra, Juan-Jesús Velasco-Vélez et al. In addition, some practical advantages demonstrated that the Ir with a high valence state is responsible for the high OER. Besides, the theoretical finding that bound Mo-Ir oxides system has high acid-stability potential has not been experimentally reported in the literature 15. Ulissi and coworkers performed systematic high-throughput calculations to discover catalysts that could replace state-of-the-art iridium oxide catalysts. Nørskov and coworkers identified 68 acid-stable candidates, such as Sb, and Mo, from 47, 814 nonbinary metal oxides for OER 16. The large-scale density functional theory (DFT) computations and emerging machine-learning techniques are greatly accelerating the innovation and discovery of catalysts 15, 28, 29. Therefore, modulating the Ir-based catalysts to achieve enhanced OER activity, while simultaneously preserving high acid-stability serves are a promising route to develop OER catalysts suitable for large-scale applications. Notably, Compared to Ru-based catalysts, Ir-based catalysts show higher stability and lower OER activity under acidic conditions 14, 25, 26, 27. However, only the performance of the state-of-the-art Ir-based and Ru-based catalysts have been expected to improve their catalytic activity and stability further 22, 23, 24. Recently, Sargent and coworkers suggested that modulating the 3d transition metal in metal (CoFe) oxyhydroxides by suitable transition metal (W) doping may provide further avenues to OER optimization 21. Xin Wang and coworkers proposed a lattice oxygen oxidation mechanism pathway using metal oxyhydroxides, when two adjacent oxidized oxygen atoms can hybridize their oxygen holes without sacrificing metal-oxygen hybridization 20. investigated (Ni, Fe)oxyhydroxides layer structures 19. developed the amorphous metal oxide ( a-Fe 100-y-zCo yNi zO x) materials 17, and Friebel et al. Among others, the first-row (3d) transition-metal oxides showed good promise as OER catalysts. Significant progress has been achieved in developing active OER catalysts, though the stability under acidic conditions is still a big issue 15, 16, 17, 18. Thus, developing low-cost and high-efficiency OER catalysts, especially those stable in acidic media, has been a pressing need but remains a grand challenge 14. As a half-reaction of water splitting, oxygen evolution reaction (OER) is a major bottleneck due to its sluggish kinetics, while the current OER catalysts typically degrade rapidly under acidic conditions, are not stable in highly oxidative environments and are of high cost 11, 12, 13. Though the alkaline water electrolysis technology is dominating the large-scale production of H 2, proton exchange membrane (PEM) water electrolysis has clear advantages such as compact configuration, larger maximum current densities, higher energy efficiency, less H 2 impurity, and dynamic flexibility of operation 7, 8, 9, 10. Among different ways of producing H 2, electrochemical water splitting plays a vital role in utilizing renewable energy sources 3, 4, 5, 6. Hydrogen (H 2) fuel, as a clean energy carrier, is promising to provide an environmentally benign solution for global energy needs 1, 2. This study suggests high stability with high catalytic performance in these materials by creating electron-deficient surfaces and provides a general, unique strategy for guiding the design of other metal-semiconductor nanocatalysts. Furthermore, the proton dissociation pathway is suggested via surface oxygen serving as proton acceptors. Remarkably, IMO with an electron-deficient metal surface (Ir x+ x > 4) exhibit a low overpotential of only ~156 mV at 10 mA cm −2 and excellent durability in acidic media due to the high oxidation state of metal on MoO 3. We systematically investigate IMO’s structure, electron transfer behaviors, and OER catalytic performance by combining experimental and theoretical studies. Herein, we introduce electron-deficient metal on semiconducting metal oxides-consisting of Ir (Rh, Au, Ru)-MoO 3 embedded by graphitic carbon layers (IMO) using an electrospinning method. The poor catalyst stability in acidic oxidation evolution reaction (OER) has been a long-time issue.
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