Linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) answer different questions about an electrocatalyst. Using each for what it does best, and reading them together, is the core skill of electrocatalysis evaluation.
LSV delivers polarization curves, overpotentials at reference current densities and Tafel slopes. Discipline: compensate series resistance and state the method; control scan rate and direction, hysteresis often signals surface restructuring; and precondition identically before each sweep. Comparing catalysts at different iR regimes or scan histories compares artifacts.
EIS separates solution resistance, charge-transfer resistance and diffusion elements across frequency. Run at a defined potential on the polarization curve, not at open circuit, and validate with Kramers-Kronig checks or at least replicate spectra. Fitting models should be physically motivated; a perfect fit with unphysical constants is decoration, not analysis.
CA at fixed potential reveals deactivation, activation and photocurrent transients under chopping. Run long enough to see the behavior you claim: a 100-second hold proves nothing about a catalyst meant to run for days. Report current density versus time with the potential and any preceding history.
Reading kinetic parameters from uncompensated data; comparing Tafel slopes across different electrolytes; using EIS without stating the potential; and stability claims from short holds. Each error is common, each is avoidable, and reviewers check for all four.
Perfectlight's electrochemical workstations support all three techniques with the automation needed for campaigns; see solutions.
