Light‐Driven Metal Exsolution‐Redissolution of High‐Entropy Oxide Enabling High‐Performance Dry Reforming of Methane

Abstract Solar‐driven dry reforming of methane (DRM) is attractive for syngas production as an energy‐efficient and environmentally friendly process. However, the remaining challenges of low yield and coke‐induced inability in this route severely limit its applicability. Here, a light‐induced metal exsolution‐dissolution strategy is reported using high‐entropy oxide (HEO) as a support for highly active and durable photothermal DRM. As evidenced by structural characterizations and theoretical simulations, the metal exsolution‐dissolution process triggers the chemical looping of oxygen vacancies on HEO, in which CH ₄ is activated to CO and H ₂ by lattice oxygen while oxygen from CO ₂ can fill the oxygen vacancy and release CO. Such a pathway greatly improves product formation and coking resistance, overcoming the limitations. As a result, the optimized CoNiFeZnCr‐HEO supported Rh nanocomposite achieves a high H ₂ /CO production of 0.242/0.246 mol g ⁻¹ h ⁻¹ with a balance selectivity of 0.98 and impressive long‐term stability (200 h). The yield is ≈300 and 450 times higher than that of quaternary and ternary oxides‐based catalysts, respectively. This work paves the way for new insights into the light‐driven DRM process and highlights the integration of dynamic surface evolution with molecular activation to enhance catalytic performance.