Proton selective adsorption on Pt-Ni nano-thorn array electrodes for superior hydrogen evolution activity

Conventional acidic water electrolysis for large-scale hydrogen production needs to involve a noble metal catalyst for the anode to resist electrochemical oxidation, while alkaline electrolysis can provide better anode protection, but hydrogen ions become a minority species, which leads to sluggish hydrogen evolution reaction (HER) kinetics. Herein, by developing a unique nano-thorn-like Pt-Ni nanowire electrode as a superior HER catalyst, we enable a local pseudo-acidic environment near the cathode surface in an alkaline electrolyzer. In such a situation, we observed dramatic enhancement of selective H+ adsorption versus K+, leading to an extremely high HER performance towards real applications, with low overpotentials (eta(geo-surface area)) of 23 mV and 71 mV at current densities of 10 mA cm(-2) and 200 mA cm(-2), respectively. This result is exceptionally better than the state-of-the-art Pt-based catalysts in an alkaline electrolyte at large current densities (>= 200 mA cm(-2)). The simulation result suggests that a strong local electric field around a nano-thorn structure can exponentially increase the diffusion rate of H+ towards the electrode surface as compared with K+, which promotes faster mass transfer and reaction kinetics for the HER in an alkaline medium.

Automated summary

By developing a unique nano-thorn-like Pt-Ni nanowire electrode as a superior HER catalyst, a local pseudo-acidic environment near the cathode surface in an alkaline electrolyzer is enabled, leading to an extremely high HER performance towards real applications. This innovative catalyst shows significantly better performance than the state-of-the-art Pt-based catalysts in an alkaline medium at large current densities.