IrOx Nanoclusters Modified by BaCO3 Enable ″Two Birds with One Stone″ in Solar-Driven Direct Unbuffered Seawater Electrolysis.

Abstract

Direct seawater electrolysis (DSE) coupled with renewable energy can maximize the sustainability of hydrogen energy acquisition by effectively alleviating the dependence on pure water resources. In a practical sense, the parallel chlorine evolution reaction (CER) of DSE opens up an opportunity to hit ″two birds with one stone″ by the dual values of anode and cathode. However, the biggest challenge is how to control the selectivity of CER to balance its values and drawbacks. Here, we use the different nucleation rates of iridium and barium ions in a weak basic solution and subsequent acid etching to devise an IrOx nanocluster (IrOx-Cs) supported BaCO3. The catalyst-support interaction between IrOx-Cs and BaCO3 enables repelling the Cl- near the electrode interface layer to achieve a controlled CER selectivity. Additionally, the mass activity of the prepared IrOx-Cs@BaCO3 is as high as 1402 A g-1Ir, which is 7.12 times higher than that of IrO2 oxides in unbuffered seawater. The photovoltaic-electrolysis device paired by IrOx-Cs@BaCO3 with controlled CER activity and Pt demonstrated that valuable active chlorine and H2 can be simultaneously obtained, with the flexibility to bind to different ion exchange membranes.