Dataset for: Understanding methane cleavage on medium-entropy oxides

This dataset accompanies the article "Understanding methane cleavage on high-entropy oxides" by Yuan, Song, Wu, and Jiang (Catalysis Science & Technology, 2026). It contains site-resolved DFT-computed adsorption energies and CI-NEB activation barriers for methane C-H scission on a model quaternary high-entropy oxide, Mg0.25Zn0.25Ni0.25Cu0.25O (100). The data are tabulated in a single CSV file with 77 rows and 5 columns: * neb — CI-NEB activation barrier for C-H scission (eV; target variable) * h — adsorption energy of an isolated H atom at the site (eV) * ch4 — adsorption energy of CH4 at the corresponding metal site (eV) * ch3 — adsorption energy of the methyl fragment at the site (eV) * co_adsorption — co-adsorption energy of the H + CH3 fragments after cleavage (eV) Adsorption energies follow the convention E_ads(X) = E_X/slab - E_X(gas) - E_slab; a more negative value indicates stronger binding. Computational details:All calculations were performed with VASP 6 using the PBE functional, PAW pseudopotentials (Ni_pv for Ni), a 450 eV plane-wave cutoff, a 3x3x1 Gamma-centred k-mesh, force and energy thresholds of 0.05 eV/A and 1e-5 eV, DFT+U on Ni 3d (U-J = 6.2 eV, Dudarev), Grimme DFT-D3 dispersion, and spin polarisation. Surface model: five-layer 4x4 Mg0.25Zn0.25Ni0.25Cu0.25O (100) slab with at least 15 A vacuum; the top two layers were relaxed while the bottom three were fixed at bulk geometry. The HEO cation sublattice was generated by random redistribution of equimolar Mg/Zn/Ni/Cu over 200 independent realisations and the configuration with one of the lowest surface energies was retained as the representative model. Transition states were located by the climbing-image nudged elastic band method with five intermediate images. The dataset is released to enable reproduction of the descriptor-based machine-learning analysis reported in the article and to support follow-up studies on methane activation over high-entropy oxide and related multicomponent-oxide catalysts.