Operando methods for the elucidation of electrolyte effects in electrocatalysis

The electrolyte pH, ion composition, and solvent are important design parameters in electrocatalytic systems, which directly impact the system’s catalytic activity, selectivity and stability. However, the relationship between the electrolyte composition and electrocatalytic performance is complex, and at present difficult to predict. To elucidate the underlying principles that govern electrolyte effects in electrocatalysis, operando techniques capable of resolving the active site structures at the electrode–electrolyte interface play a crucial role. Here, we review the current capabilities of these operando techniques and analyze how they can be used to find the rules of the game for electrolyte engineering. • In electrocatalysis, ion-solvent-electrode interactions steer the system's performance. • Experimental methodologies to resolve these interactions are reviewed. • The need for a more generalized view of electrolyte effects with predictive value is highlighted.