Manzoor, U., Mujica Roncery, L., Raabe, D. & Souza Filho, I. R. Sustainable nickel enabled by hydrogen-based reduction. Nature 641, 365–373 (2025).
Spreitzer, D. & Schenk, J. Reduction of iron oxides with hydrogen—a review. Steel Res. Int. 90, 1900108 (2019).
Chee, S. W., Lunkenbein, T., Schlögl, R. & Roldán Cuenya, B. Operando electron microscopy of catalysts: the missing cornerstone in heterogeneous catalysis research? Chem. Rev. 123, 13374–13418 (2023).
Chenna, S., Banerjee, R. & Crozier, P. A. Atomic-scale observation of the Ni activation process for partial oxidation of methane using in situ environmental TEM. ChemCatChem 3, 1051–1059 (2011).
Zeng, L., Cheng, Z., Fan, J. A., Fan, L. S. & Gong, J. Metal oxide redox chemistry for chemical looping processes. Nat. Rev. Chem. 2, 349–364 (2018).
Wei, S., Ma, Y. & Raabe, D. One step from oxides to sustainable bulk alloys. Nature 633, 816–822 (2024).
Kim, J. Y., Rodriguez, J. A., Hanson, J. C., Frenkel, A. I. & Lee, P. L. Reduction of CuO and Cu2O with H2: H embedding and kinetic effects in the formation of suboxides. J. Am. Chem. Soc. 125, 10684–10692 (2003).
Wang, X., Hanson, J. C., Frenkel, A. I., Kim, J.-Y. & Rodriguez, J. A. Time-resolved studies for the mechanism of reduction of copper oxides with carbon monoxide: complex behavior of lattice oxygen and the formation of suboxides. J. Phys. Chem. B 108, 13667–13673 (2004).
Rodriguez, J. A., Hanson, J. C., Frenkel, A. I., Kim, J. Y. & Pérez, M. Experimental and theoretical studies on the reaction of H2 with NiO: Role of O vacancies and mechanism for oxide reduction. J. Am. Chem. Soc. 124, 346–354 (2002).
Luo, L. et al. Atomic origins of water-vapour-promoted alloy oxidation. Nat. Mater. 17, 514–518 (2018).
Sun, X. et al. Dislocation-induced stop-and-go kinetics of interfacial transformations. Nature 607, 708–713 (2022).
Zou, L., Li, J., Zakharov, D. N., Stach, E. A. & Zhou, G. In situ atomic-scale imaging of the metal/oxide interfacial transformation. Nat. Commun. 8, 307 (2017).
Yuan, W. et al. Visualizing H2O molecules reacting at TiO2 active sites with transmission electron microscopy. Science 367, 428–430 (2020).
Lagrow, A. P., Ward, M. R., Lloyd, D. C., Gai, P. L. & Boyes, E. D. Visualizing the Cu/Cu2O interface transition in nanoparticles with environmental scanning transmission electron microscopy. J. Am. Chem. Soc. 139, 179–185 (2017).
Sun, X. et al. Atomic origin of the autocatalytic reduction of monoclinic CuO in a hydrogen atmosphere. J. Phys. Chem. Lett. 12, 9547–9556 (2021).
Frey, H., Beck, A., Huang, X., van Bokhoven, J. A. & Willinger, M. G. Dynamic interplay between metal nanoparticles and oxide support under redox conditions. Science 376, 4–8 (2022).
Rukini, A., Rhamdhani, M. A., Brooks, G. A. & Van den Bulck, A. Metals production and metal oxides reduction using hydrogen: a review. J. Sustain. Metall. 8, 1–24 (2022).
Chen, J. & Hayes, P. C. Mechanisms and kinetics of reduction of solid NiO in CO/CO2 and CO/Ar gas mixtures. Metall. Mater. Trans. B 50, 2623–2635 (2019).
Krasuk, J. H. & Smith, J. M. Kinetics of reduction of nickel oxide with CO. AIChE J. 18, 506–512 (1972).
Antola, O., Holappa, L. & Paschen, P. Nickel ore reduction by hydrogen and carbon monoxide containing gases. Miner. Process. Extr. Metall. Rev. 15, 169–179 (1995).
Scholz, J. J. & Langell, M. A. Kinetic analysis of surface reduction in transition metal oxide single crystals. Surf. Sci. 164, 543–557 (1985).
Wang, J. et al. Effect of the chemical states of copper on methanol decomposition and oxidation. J. Phys. Chem. C 128, 4559–4572 (2024).
Swallow, J. E. N. et al. Revealing the role of CO during CO2 hydrogenation on Cu surfaces with in situ soft X-ray spectroscopy. J. Am. Chem. Soc. 145, 6730–6740 (2023).
Peck, M. A. & Langell, M. A. Comparison of nanoscaled and bulk NiO structural and environmental characteristics by XRD, XAFS, and XPS. Chem. Mater. 24, 4483–4490 (2012).
Furstenau, R. P., McDougall, G. & Langell, M. A. Initial stages of hydrogen reduction of NiO(100). Surf. Sci. 150, 55–79 (1985).
Norby, T. Protonic defects in oxides and their possible role in high temperature oxidation. J. Phys. IV 3, C9-99–C9-106 (1993).
Li, S., Ding, W., Meitzner, G. D. & Iglesia, E. Spectroscopic and transient kinetic studies of site requirements in iron-catalyzed Fischer–Tropsch synthesis. J. Phys. Chem. B 106, 85–91 (2002).
Janbroers, S., Crozier, P. A., Zandbergen, H. W. & Kooyman, P. J. A model study on the carburization process of iron-based Fischer–Tropsch catalysts using in situ TEM–EELS. Appl. Catal. B 102, 521–527 (2011).
Andersson, D. A., Simak, S. I., Skorodumova, N. V., Abrikosov, I. A. & Johansson, B. Optimization of ionic conductivity in doped ceria. Proc. Natl Acad. Sci. USA 103, 3518–3521 (2006).
Matsubu, J. C. et al. Adsorbate-mediated strong metal-support interactions in oxide-supported Rh catalysts. Nat. Chem. 9, 120–127 (2017).
Sun, X. et al. Atomic‐scale mechanism of unidirectional oxide growth. Adv. Funct. Mater. 30, 1906504 (2020).
Boyes, E. D. & Gai, P. L. Environmental high resolution electron microscopy and applications to chemical science. Ultramicroscopy 67, 219–232 (1997).
Gai, P. L. et al. Atomic-resolution environmental transmission electron microscopy for probing gas-solid reactions in heterogeneous catalysis. MRS Bull. 32, 1044–1050 (2007).
Gai, P. L., Lari, L., Ward, M. R. & Boyes, E. D. Visualisation of single atom dynamics and their role in nanocatalysts under controlled reaction environments. Chem. Phys. Lett. 592, 355–359 (2014).
LaGrow, A. P., Lloyd, D. C., Gai, P. L. & Boyes, E. D. In situ scanning transmission electron microscopy of Ni nanoparticle redispersion via the reduction of hollow NiO. Chem. Mater. 30, 197–203 (2018).
Helveg, S. et al. Atomic-scale imaging of carbon nanofibre growth. Nature 427, 426–429 (2004).
Yoshida, H. et al. Visualizing gas molecules interacting with supported nanoparticulate catalysts at reaction conditions. Science 335, 317–319 (2012).
Xie, D. G. et al. In situ study of the initiation of hydrogen bubbles at the aluminium metal/oxide interface. Nat. Mater. 14, 899–903 (2015).
Leapman, R. D., Grunes, L. A. & Fejes, P. L. Study of the L23 edges in the 3d transition metals and their oxides by electron-energy-loss spectroscopy with comparisons with theory. Phys. Rev. B 26, 614–635 (1982).
Sparrow, T. G., Williams, B. G., Rao, C. N. R. & Thomas, J. M. L3/L2 white-line intensity ratios in the electron energy-loss spectra of 3d transition-metal oxides. Chem. Phys. Lett. 108, 547–550 (1984).
Grosvenor, A. P., Biesinger, M. C., Smart, R. S. C. & McIntyre, N. S. New interpretations of XPS spectra of nickel metal and oxides. Surf. Sci. 600, 1771–1779 (2006).
Carley, A. F., Jackson, S. D., O’Shea, J. N. & Roberts, M. W. The formation and characterisation of Ni3+—an X-ray photoelectron spectroscopic investigation of potassium-doped Ni (110)–O. Surf. Sci. 440, L868–L874 (1999).
McIntyre, N. S. & Zetaruk, D. G. X-ray photoelectron spectroscopic studies of iron oxides. Anal. Chem. 49, 1521–1529 (1977).
Zhao, X. et al. Multiple metal-nitrogen bonds synergistically boosting the activity and durability of high-entropy alloy electrocatalysts. J. Am. Chem. Soc. 146, 3010–3022 (2024).
Anisimov, V. I., Zaanen, J. & Andersen, O. K. Band theory and Mott insulators: Hubbard U instead of Stoner I. Phys. Rev. B 44, 943 (1991).
Kresse, G. & Furthmüler, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).
Kresse, G. & Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 6, 15–50 (1996).
Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).
Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758 (1999).
Xu, Q., Cheah, S. & Zhao, Y. Initial reduction of the NiO(100) surface in hydrogen. J. Chem. Phys. 139, 024704 (2013).
Ferrari, A. M., Pisani, C., Cinquini, F., Giordano, L. & Pacchioni, G. Cationic and anionic vacancies on the NiO(100) surface: DFT + U and hybrid functional density functional theory calculations. J. Chem. Phys. 127, 174711 (2007).
Jeon, J., Yu, B. D. & Hyun, S. Adsorption properties of transition metal atoms on strongly correlated NiO(001) surfaces with surface oxygen vacancies. Curr. Appl. Phys. 15, 679–682 (2015).
Silvi, B. & Savin, A. Classification of chemical bonds based on topological analysis of electron localization functions. Nature 371, 683–686 (1994).
Jónsson, H., Mills, G. & Jacobsen, K. W. in Classical and Quantum Dynamics in Condensed Phase Simulations (eds Berne, B. J. et al.) 385–404 (World Scientific, 1998).
He, Y., Dulub, O., Cheng, H., Selloni, A. & Diebold, U. Evidence for the predominance of subsurface defects on reduced anatase TiO2(101). Phys. Rev. Lett. 102, 106105 (2009).
Yu, J., Rosso, K. M. & Bruemmer, S. M. Charge and ion transport in NiO and aspects of Ni oxidation from first principles. J. Phys. Chem. C 116, 1948–1954 (2012).
Wagner Jr, J. B. in Defects and Transport in Oxides (eds Seltzer, M. S. & Jaffee, R. I.) 283–301 (Springer, 1974).
Malyshev, O. B. & Middleman, K. J. In situ ultrahigh vacuum residual gas analyzer ‘calibration’. J. Vac. Sci. Technol. A 26, 1474–1479 (2008).
