Work

Interfacial engineering to create ionically bonded heterostructures for ampere-level chlorine-free anodic reactions in seawater

Year: 2024

Type: article

Abstract: Production of hydrogen directly from seawater can be a sustainable method; however, corrosive and competitive chlorine chemistry at the anode interfere with the oxygen evolution reaction (OER). Special materials need to be designed to avoid chlorine chemistry; hence, a two-dimensional metal-organic framework@WO 3 .B 2 O 3 (MOF@WB) heterostructure with ionic bonds was engineered, which can deliver ∼10x better performance and is ∼65 % more economical than commercial IrO 2 for OER. Our system is stable in alkaline seawater for over 1000 h without chlorine evolution and remains functional even after sitting idle for 5 days, making it integrable with renewable power sources. The catalyst also operated stably at the industrial-scale current density of 1.58 A cm −2 for over 100 h with 99 % performance retention in alkaline seawater. Theoretical calculations reveal that B assists in the adsorption of the MOF on the WO 3 substrate via the creation of ionic bonds , resulting in optimized surface geometries for selective reactions, which safeguard against chlorine chemistry. B 2 O 3 helps modulate the B-OH sites at the interface via B-O-B bond hydrolysis, activating the OER kinetics, hence providing an ideal platform for effective direct seawater catalysis to produce low-cost hydrogen.

Source: Applied Catalysis B: Environmental

DOI: 10.1016/j.apcatb.2024.124800