Successful synthesis of a ceramic-supported ultrathin carbon membrane with unprecedently high hydrogen permeance and outstanding H₂/CO₂, H₂/N₂ and H₂/CH₄ selectivities at elevated temperatures.

Hydrogen (H₂) produced from renewables will have a growing impact on the global energy dynamics towards sustainable and carbon‐neutral standards. The share of green H₂ is still too low to meet the net‐zero target, while the demand for high‐quality hydrogen continues to rise. These factors amplify the need for economically viable H₂ generation technologies. The present article aims at evaluating the existing technologies for high‐quality H₂ production based on solar energy. Technologies such as water electrolysis, photoelectrochemical and solar thermochemical water splitting, liquid metal reactors and plasma conversion utilize solar power directly or indirectly (as carbon‐neutral electrons) and are reviewed from the perspective of their current development level, technical limitations and future potential.

We show manufacturing of 25 cm² BZCY half-cells by tape-casting of assemblies with electrolyte thickness 10–20 μm. BaY₂NiO₅ transient liquid phase formation is analysed and proton conductivity with values of σ = 0.003 S cm⁻¹ at 600 °C is shown.

Lanthanum tungstate (LWO) and LWO with 20 at.% and 35 at.% molybdenum substituting tungsten were prepared by the Pechini method. Phase purity and successful Mo substitution inside these dense LWO membrane materials were confirmed by conventional and high resolution transmission electron microscopy techniques. The split of La₂/W₂ site by around 0.3 Å was proven. Extra reflections show up in the diffraction patterns from Mo-substituted LWO, and together with simulations, these reflections were recognized as forbidden reflections in a non-substituted LWO system, while the extinction rules are broken by Mo substitution due to the different scattering factors of W and Mo. Energy-dispersive X-ray chemical mapping allowed direct visualization of individual atomic columns, and revealed that all Mo is located at the W₁ sites in the Mo-substituted LWO. Moreover, the diffuse scattering in diffraction patterns provides direct evidence of short range clustering of oxygen vacancies and could be further related to the oxygen conduction of the LWO membranes.