Membrane photocathode assembly suitable for gas-phase operation with performance suitable for integration into a tandem cell for 10% STH efficiency

A set of photocathode membrane assemblies with included protection layers and/or HER electrocatalysts, with at least one asssembly that achieves (or has a concrete action plan to achieve) a water splitting photocurrent of 8.2 mA/cm2 under standard solar illumination.