Nanoscaling and Heterojunction for Photocatalytic Hydrogen Evolution by Bimetallic Metal-Organic Frameworks

Using sunlight to manufacture hydrogen offers promising access to renewable clean energy. For this, low-cost photocatalyst with effective light absorption and charge transfer are crucial, as current top-performing systems often involve precious metals like Pd and Pt. An integrated organic-inorganic photocatalyst based on the cheap metals of iron and nickel are reported, wherein the metal ions form strong metal-sulfur bonds with the organic linker molecules (2,5-dimercapto-1,4-benzenedicarboxylic acid, H4DMBD) to generate 2D coordination sheets for promoting light absorption and charge transport. The 2D sheets are further modified through ionic metal-carboxylate moieties to allow for functional flexibility. Thus, high-surface-area thin nanosheets of this 2D material, with an optimized Fe/Ni ratio (0.25:1.75), and in heterojunction with CdS nanosheet, achieve a stable photocatalytic hydrogen evolution rate of 12.15 mu mol mg(-1) h(-1). This work synergizes coordination network design and nano-assembly as a versatile platform for catalyzing hydrogen production and other sustainable processes.