Desert Beetle Inspired Heterogeneous Electrode for Large Current Density Hydrogen Evolution Reaction

Abstract

The hydrogen (H₂) evolution reaction (HER) is a pivotal process in the production of green H₂, which will play a crucial role in future sustainable energy systems. Despite extensive efforts to optimize catalyst activity, great challenges related to H₂ mass transfer at the electrode interface still impede the improvement of HER efficiency. Here, a catalytic system inspired is designed by the desert-beetle's hydrophilic/hydrophobic patterned back, a natural structure capable of condensing and transporting fog droplets. This catalytic system is composed of superaerophobic (SAB) electrocatalytic catalyst dots surrounded with superaerophilic (SAL) coating, which can efficiently enhance the gaseous and dissolved H₂ mass transfer to achieve exceptional HER performance. Such a desert beetle-inspired structure using platinum (Pt) as catalyst achieves an excellent current density of HER (−1252 mA cm⁻²) at −0.5 V versus RHE, which is 2 times higher than the conventional Pt electrode (−408.5 mA cm⁻²). The overpotential required to achieve −10 mA cm⁻² is only −7 mV, compared to −25 mV on the conventional electrode. This catalytic system is also applicable to various catalysts (e.g., Re-Co, Co-Cu, Co-Mo, Cu-Mo, and Ni-Mo), which exhibit a minimum 200% current density increase, as compared with their conventional electrode structures.