IrO_x 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–1 Ir, 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.

Progress and Perspectives for Solar‐Driven Water Electrolysis to Produce Green Hydrogen

“…The negatively charged BaCO 3 in IrO x -Cs@BaCO 3 catalyst plays a role of repelling Cl − in seawater through Coulomb's law and endowing inhibition of the Cl − diffusion near the electric double layer, thus contributing to the reduced ClER selectivity. [196] Similar results can be seen in the NiFe/NiS x -Ni catalyst, wherein the NiFe hydroxide layer coated on a NiS x layer formed on Ni foam, the NiS x layer generated a cation-selective polyatomic anion-rich anode stable against chloride etching or corrosion. [197] Furthermore, self-powered direct seawater electrolysis has been fabricated to guarantee an unintermittent and stable H 2 generation.…”

Synergetic Function of the Single-Atom Ru–N4 Site and Ru Nanoparticles for Hydrogen Production in a Wide pH Range and Seawater Electrolysis

“…The development and application of hydrogen have become the focus of energy and technology since this century, and it is likely to have a transformative impact on lifestyle and industry production. , The fuel cell industry, which is the most related to hydrogen energy, has an indispensable demand for clean hydrogen sources. Electrocatalytic water splitting has become an important way to produce clean hydrogen. − Due to the global shortage of freshwater resources, electrolytic seawater has become a research hotspot. − The principle of seawater electrolysis is basically the same as that of freshwater electrolysis, but it is more corrosive than freshwater due to the complex composition of seawater . More importantly, due to the high concentration of chloride ions in seawater, chloride-ion oxidation reaction will occur in the process of electrolyzing water to produce highly corrosive substances such as hypochlorite, which will accelerate the corrosion of electrolyzed water devices. , To overcome the sluggish kinetics and high overpotentials of the hydrogen evolution reaction (HER), efficient catalysts are needed to facilitate the dissociation of the H 2 O molecule or the desorption of the H 2 molecule.…”

Recent Advances on Hydrogen Evolution and Oxygen Evolution Catalysts for Direct Seawater Splitting

“…Du et al prepared IrO x -Cs@BaCO 3 [32] whose charge transfer interaction between IrO x -Cs and BaCO 3 could force a more negative charge on BaCO 3 , so as to repel Cl − anions in seawater. The IrO x -Cs@BaCO 3 with low content of Ir achieved a high mass activity of 1402 A g −1 in the real seawater, and its stability is close to that of IrO 2 [32]. Haq et al embedded Au-modified Gd-Co 2 B nanosheets into TiO 2 nanosheets grown on Ti chaff (Au-GdCo 2 B@TiO 2 ) (Figure 5a) [33].…”