3D‐Printed Electrode Support Development for pH‐Neutral Oxygen Evolution Reaction Electrocatalysis

Abstract Developing a high‐performance, low‐cost, all pH‐responsive conductive support electrode for oxygen evolution reaction (OER) is challenging for advanced water electrolyzers. In this study, we developed a practical and single‐step scalable approach for activating porous 3D‐printed electrodes (3DPE) using heat treatment. Interestingly, an interconnected particle morphology with uniform pores (149.4 ± 70.2 nm) evolved in ammonia tread 3DPE, which was absent in the argon environment‐activated electrode. Also, the enhanced anodic/cathodic ion diffusion coefficient from Ar‐300 (1.26 × 10 −4 cm 2 s −1 ) to Am‐300 (1.659 × 10 −4 cm 2 s −1 ) signified the active participation of the macropore in the presence of inner redox probe (ferro/ferricyanide). The improved electron transfer rates of 5.36 × 10 −4 and 2.79 × 10 −4 cm 2 s −1 were observed in the Am‐300 and Ar‐300 electrodes, respectively. The activated Am‐300 support electrode showed an OER activation overpotential of 466 mV and 686 mV under N 2 ‐saturated 0.5 M KOH and 0.5 M H 2 SO 4 electrolyte. The notable activity of the Am‐300 electrodes has been attributed to the combined effect of enhanced electronic conductivity, high density of macro/mesoporosity, and remarkable modulation of the double layer capacitance ( C dl ), which enabled higher accessibility of reactant. The electrode activation strategy developed in the present study can provide a simple and scalable approach toward developing a free‐standing electrode and its direct impact on the active site support for the pH‐neutral OER catalysts.