Flow-through porous electrode for enhanced oxygen evolution reaction by promoting gas bubble release from water splitting

•CoS2@Ni flow-through porous electrodes were prepared for OER.•Flow-through operation can shorten bubble growth time and reduce bubble size.•Overpotential for OER can be decreased by about 100 mV.•Energy required for hydrogen production reduced by 0.22 kWh/Nm3. Several CoS2/Ni flow-through porous electrodes are fabricated to promote gas bubble release for enhanced oxygen evolution reaction. Structural characterization shows that CoS2 catalyst is immobilized on the porous Ni substrate. The bubble average diameter can be decreased from 29.21 ± 17.9 μm to 13.38 ± 5.05 μm, and the desorption time is decreased from 1.615 s to 0.067 s, with the electrolyte velocity increasing from 0 cm/s to 2.89 cm/s at the current density of 100 mA/cm2. A mathematical model is proposed to describe gas bubble growth, which is found that higher current density is not bring much bigger gas bubble. The overpotential of the CoS2/Ni electrode for OER is 498 mV at 100 mA/cm2. The overpotential of CoS2/Ni electrode can be decreased from 754 mV to 661 mV with the electrolyte velocity increase from 0 cm/s to 9.42 cm/s at 200 mA/cm2 with the energy required for hydrogen production reduced by 5.01 kWh/kmol.