VAVenu Gopal Agarwal

← Research · Collaboration

Field-enhanced dissociation of buffer species

ACS Electrochemistry · 2025
Schematic: Near a hydrogen-evolving electrode the strong interfacial field dissociates buffer molecul
Near a hydrogen-evolving electrode the strong interfacial field dissociates buffer molecules, raising the local free-proton concentration above the bulk.

Strong interfacial electric fields can accelerate the dissociation of protonated buffer species, changing the local pH near electrodes and membranes.

Key findings

  • Generalised modified Poisson–Nernst–Planck model with electric-field-enhanced (second Wien effect) dissociation, for unbuffered KClO4 and buffered carbonate and phosphate electrolytes.
  • With buffers, field-enhanced protolysis lets free protons act as HER reactants above several hundred mA cm−2.
  • In the diffuse layer the effective proton concentration exceeds the bulk value.
  • A strong field sensitivity can overestimate water dissociation, especially in unbuffered electrolytes.

What I did

  • Numerical analysis of field-enhanced homogeneous dissociation of protonated buffer species.
M. Wada, K. Obata, V. G. Agarwal, F. Lorenzutti, S. Haussener, K. Takanabe, ACS Electrochemistry (2025).