Increasing the performance of seawater electrolyser and enabling direct natural seawater feed by asymmetric electrolyte flow scheme.

No abstract

A modular, multicomponent catalyst design principle is introduced and exemplified using a three-component, oxygen reduction reaction/oxygen evolution reaction (ORR/OER) catalyst designed for the oxygen electrode of unitized reversible fuel cells (URFCs). The catalyst system exhibited unprecedented catalytic performance in liquid electrolyte and in single unitized reversible fuel cell tests. The distinct components, each active for either ORR or OER, are prepared and optimized independently of each other and physically mixed during electrode preparation. The new modular URFC catalyst, Cu-α-MnO 2 /XC-72R/NiFe-LDH, combined a carbon-supported, Cu-stabilized α-MnO 2 ORR catalyst with a NiFe-LDH OER catalyst and displayed improved activity and stability under URFC cycling compared to platinum group metal references.Stepwise modular optimization of the carbon and the interlayer anions of the OER component led to a further improved derivative, Cu-α-MnO 2 /O-MWCNTs/NiFe-LDH-Cl − . This URFC catalyst outperformed all previous materials in terms of its combined overpotential η ORR-OER and performance stability in the rotating disk electrode (RDE) scale. Its single-cell performance is analyzed and discussed.

Anion exchange membrane water electrolysis (AEMWE) is an attractive emerging green hydrogen technology. However, the scaling of trends in activity of anode catalysts for the oxygen evolution reaction (OER) from a liquid-electrolyte, three-electrode environment to the two-electrode single-cell format has remained poorly considered. Herein, we critically investigate the scaling of kinetic and catalytic properties of a family of highly active Ni foam (NF) supported, anion (A–)-tuned NiFe­(-A–)-OER catalysts. Trends in catalytic activity suggest impressive improvements of up to 91-fold in three-electrode setups (3LC) compared to uncoated NF. While we demonstrate the successful qualitative structure–performance tunability in a 5 cm2 AEMWE single cell, we also find serious limitations in the quantitative predictability of three-electrode setups for single-cell performance trends. Cell environments appear to equalize the cell performances of designer catalysts, which has important ramifications for electrode development. We succeed in analyzing and discussing some of these translation limitations in terms of previously overlooked effects summarized in the activity improvement factor f.