Solar Thermochemical Water-Splitting Reaction Enhanced by Hydrogen Permeation Membrane

TL;DR

This study demonstrates that using a hydrogen permeable membrane significantly enhances the efficiency and conversion rate of solar thermochemical water splitting at high temperatures, offering a promising approach for hydrogen production.

Contribution

First thermodynamic analysis of hydrogen permeable membrane in solar water splitting, showing substantial efficiency improvements over oxygen permeation membranes.

Findings

Conversion rate increased to 87.8% at 1500°C

Thermodynamic efficiency reached 59.1%

Simulated solar-to-electric efficiency of 3.05%

Abstract

The low conversion rate and efficiency always weaken the performance of thermochemical water-splitting reaction. Herein, we, for the first time, conducted the thermodynamic study of a hydrogen permeable membrane (HPM) in an isothermal thermochemical water-splitting reaction driven by solar energy, which has showed a sharply enhanced conversion rate of 87.8% at 1500 oC and 10-5 atm at permeated side (versus 1.26% with oxygen permeation membrane). According to thermodynamic analysis, the first-law thermodynamic efficiency can reach as high as 59.1%. When taking solar-to-electric efficiency and vacuum pump efficiency into account (for converting separation work into solar energy), we simulated the appreciable efficiency of 3.05% at 1500 oC. The numerical model will provide guidance for the actual production of hydrogen by high temperature solar water splitting. Such novel work manifests the great significance of constructing a HPM reactor for efficient solar thermochemical water splitting, which shows a novel approach for high-temperature solar water splitting.