Absolutely Sealed Gas-Tight Replaceable Membrane H-Cell

What it is and how it works

The Absolutely Sealed Gas-Tight Replaceable Membrane H-Cell is a two-compartment electrochemical reactor designed for experiments that require (i) separation of anode and cathode products and (ii) controlled headspace conditions. The compartments are separated by an ion-exchange membrane (AEM/CEM), which allows ionic conduction while reducing molecular crossover. This improves selectivity and interpretability in electrolysis and electrocatalysis studies, especially when products are sampled for analysis.

Standard construction features

• Cell body: chemically resistant borosilicate glass for aqueous and many non-aqueous electrolytes
• Replaceable membrane clamp: compression sealing for repeatable assembly and rapid membrane swaps
• Gas-tight electrode ports: PTFE cap/cover with O-ring or compression sealing to minimise oxygen ingress and solvent evaporation
• Two-chamber geometry: supports independent electrolyte compositions (e.g., different pH, different supporting salts, different catalysts)
  
  

Optional configurations & accessories (application-driven)

• Valve / gas-handling ports: for purge/vent, controlled gas feed (e.g., CO₂), headspace sampling, and pressure equalisation
• Optical window (e.g., quartz): for photoelectrochemistry or spectroelectrochemistry where optical access is required
• Jacketed temperature-control version: for circulating thermostated fluid to stabilise kinetics, solubility, and gas–liquid equilibria
• Electrode fixtures/adaptors: to suit planar electrodes, gas-diffusion electrodes, or specific reference electrode formats
  
  

Gas-tight (absolutely sealed) vs standard screw-cap H-cell: which to choose

Choose gas-tight when you need:

• Quantitative gas experiments (CO₂RR/HER/OER) where leaks or air ingress distort faradaic efficiency and gas composition
• Stable electrolyte concentration during long runs (reduced evaporation and CO₂ loss)
• Air-sensitive chemistries (oxygen/moisture-sensitive catalysts, non-aqueous electrolytes, metal plating/stripping)
• Reproducible headspace control for mechanistic comparisons across conditions
  
  

Choose a screw-cap H-cell when:

• Running routine aqueous screening where minor air exchange is acceptable
• You are not quantifying gas products and short experiments minimise evaporation impacts
• You prioritise fast setup and lower complexity for early-stage catalyst benchmarking or teaching labs
  
  

Typical applications and instrumentation pairing

Common uses include CO₂ reduction, selective electrolysis with product separation, membrane screening, corrosion inhibitor studies, and half-cell investigations. Pair with a suitable potentiostat/galvanostat, reference electrodes, and (when needed) gas handling and downstream analytics. ScienceGears can help specify membrane type, sealing consumables, and compatible electrochemical instrumentation and accessories.