Electrocatalytic degradation of organic pollutants is a promising strategy for water purification as it does not require toxic 

chemicals, heating, or harsh conditions. It is energy efficient compared to photocatalysis and produces little to no harmful 

side-products. An essential part of the electrocatalytic system is the anode layer of the electroactive substrate. Numerous 

metal oxide systems, BDD, and their modifications have been developed recently as electrocatalysts, demonstrating exceptional

activity and energy efficiency. However, most of these developments were tested only in batch processes, while 

flow testing is critical for validating electrocatalytic systems. This study investigates the anodic oxidation of the organic 

dye pollutant Reactive Black 5 (RB-5, 20 mg/L) in a flow electrochemical reactor using a novel Ti/SnO2-Sb/α,β-PbO2-Ho 

anode. Complete decolorization of RB-5 was achieved within 90 min at 15 mA/cm2

 and 190 mL/min with low energy 

consumption (12.5 kWh/m3

). The optimized flow regime provided high efficiency and reusability of the Ho-doped PbO2

anode. Despite long-term stability of the anode, it exhibited significant Pb leaching caused by hydrodynamic shear stress 

and non-uniform current distribution. Leaching was crystal facet selective, eroding the most thermodynamically stable 

one. Active volt-induced recrystallization of β-PbO2 layer was hypothesized to through active dissolution-redisposition 

of Pb-species.