posted on 2023-11-14, 16:37authored byShanshan Lu, Zhipu Zhang, Bin Zhang, Yanmei Shi
The difference between solution pH and local pH near
an electrode
surface greatly determines the electrocatalytic performance. However,
there is still a lack of a facile and universal method for the local
pH detection of various electrode reactions, leaving the origin of
local pH changes unclear. Herein, by using phosphate species in phosphate
buffer solution (PBS) as the pH probe, we demonstrate a universal
local pH detection strategy through in situ Raman
spectroscopy for various electrode reactions. Oxygen evolution is
chosen as the example to detect the potential-dependent local pH change.
Then the strategy extends to nitrate reduction, nitrobenzene reduction,
and benzylamine oxidation. By comparing the local pH changes in different
reactions, we reveal that the local pH change is strongly dependent
on the reaction current, the ability of the system to replenish the
local H+/OH–, and the number of H+/OH– per electron transfer of the electrode
reaction.