Core-Shell Structured V-Doped CoPx@FeOOH for Efficient Seawater Electrolysis

As a renewable energy conversion method, the hydrogen from seawater electrolysis needs to overcome problems such as chlorination reaction and corrosion resistance. Considering these questions, it is vital to design a highly efficient and corrosion-resistant catalyst. Here, we developed a vanadium-doped cobalt phosphide encapsulated within an iron oxyhydroxide shell (V-CoPx@FeOOH) as an efficient core-shell electrocatalyst for the oxygen evolution reaction (OER) in seawater electrolytes. In particular, the OER overpotential of the V-CoPx@FeOOH catalyst at 100 mA cm⁻² was 270 mV. Notably, V-CoPx||V-CoPx@FeOOH was able to operate in alkaline seawater at 500 mA cm⁻² for more than 1000 h, showing excellent stability. Density functional theory (DFT) calculations indicate that the enhanced HER activity is attributed to the introduction of V, which strengthens the bonding between Co sites and H atoms, and the optimized OER activity results from the presence of both V and Fe, which together optimize the bonding strength between Co sites and OOH intermediates. The highly efficient catalyst of the core-shell structure has great prospects for overall water/seawater electrolysis.