Electrochemical Pumping for Challenging Hydrogen Separations

Abstract

Conventional hydrogen separations from reformed hydrocarbons often deploy a water gas shift (WGS) reactor to convert CO to CO2, followed by adsorption processes to achieve pure hydrogen. The purified hydrogen is then fed to a compressor to deliver hydrogen at high pressures. Electrochemical hydrogen pumps (EHPs) featuring proton-selective polymer electrolyte membranes (PEMs) represent an alternative separation platform with fewer unit operations because they can simultaneously separate and compress hydrogen continuously. In this work, a high-temperature PEM (HT-PEM) EHP purified hydrogen to 99.3%, with greater than 85% hydrogen recovery for feed mixtures containing 25–40% CO. The ion-pair HT-PEM and phosphonic acid ionomer binder enabled the EHP to be operated in the temperature range from 160 to 220 °C. The ability to operate the EHP at an elevated temperature allowed the EHP to purify hydrogen from gas feeds with large CO contents at 1 A cm–2. Finally, the EHP with the said materials displayed a small performance loss of 12 μV h–1 for purifying hydrogen from syngas for 100 h at 200 °C.

Gas Diffusion Electrodes for CO2 and N2 Reduction: A Virtual Issue

“…28,29 An electrochemical hydrogen pump for purifying hydrogen up to 99.3% from reformed hydrocarbon mixtures (e.g., gases that contain 3%, 25%, and 40% CO) has been demonstrated using the permeability of H + ions in ion-pair high-temperature polymer electrolyte membranes and phosphonic acid ionomer binders in the temperature range from 160 to 220 °C. 30 The papers included in this Virtual Issue provide the recent developments in the reduction of CO 2 and N 2 using a GDE that collectively pave the way to improve the design of devices with controlled selectivity, higher rates, higher efficiencies, and longer reactor lifetimes.…”

“…Solar-driven CO 2 reduction using a GDE directly powered by a GaInP/GaInAs/Ge triple-junction photovoltaic cell exhibited a solar-to-CO energy conversion efficiency of 19.1% under 1 sun illumination conditions . Further, GDEs have been used for NO reduction to NH 3 with liquid- and solid-state electrolytes, demonstrating the versatility of this method. , An electrochemical hydrogen pump for purifying hydrogen up to 99.3% from reformed hydrocarbon mixtures (e.g., gases that contain 3%, 25%, and 40% CO) has been demonstrated using the permeability of H + ions in ion-pair high-temperature polymer electrolyte membranes and phosphonic acid ionomer binders in the temperature range from 160 to 220 °C …”

Hydrogen deblending future and emerging technology watch

“…11,56 EHP can simultaneously separate and compress H2, and has been demonstrated to produce 99.3% purity H2 from syngas. 57…”

Photoelectrocatalytic Reforming of Polyol‐based Biomass into CO and H2 over Nitrogen‐doped WO3 with Built‐in Electric Fields

“…Targeting this problem, different from the current study that tried to suppress the CO formation [29][30][31][32] or remove CO after reaction, [33,34] herein, we report the photoelectrocatalytic reforming of biomass into CO and H 2 under room temperature using a divided photoelectrochemical (PEC) cell. In such a divided PEC cell (Scheme 1), photogenerated holes migrate on the photoanode surface for the oxidation of biomass to CO and H + , and the photogenerated electrons from the photoanode inflow into the cathode for reduction of H + to H 2 .…”