Electrocatalytic Hydrogen Generation from Seawater at Neutral pH on a Corrosion-Resistant MoO3/Ti-Felt Electrode

Using seawater can reduce the dependence on freshwater resources to generate hydrogen by electrocatalytic water splitting. However, the stability and activity of hydrogen evolution reaction (HER) electrocatalysts are highly influenced by the pH of seawater. In this regard, the development of the practical application of HER depends on the creation of highly active non-noble metal electrocatalysts. Here, we propose a technique to optimize the electrocatalytic activity and stability of MoO₃ by utilizing titanium felt as the substrate. We show an HER overpotential as low as 83 mV at −10 mA cm^–2 in neutral pH conditions. The present results show that electrocatalysts based on earth-abundant metals can perform well in saltwater HER, especially at a near-neutral pH (pH ∼ 7). In a neutral saltwater electrolyte (0.55 M PBS + 0.5 M NaCl), this electrocatalyst showed stable performance for 250 h at a constant current density of −100 mA cm^–2, indicating its promising application in seawater-based hydrogen generation. Compared with noble metals, this electrocatalyst provides a cost-effective option for economic seawater hydrogen generation, promoting the potential of seawater electrolysis.

A technique to optimize the electrocatalytic activity and stability of MoO₃ by utilizing titanium felt as the substrate is proposed, and an HER overpotential as low as 83 mV at −10 mA cm⁻² in neutral pH conditions is achieved.