Hydrogen Boride Sheets and Copper Nanoparticle Composites as a Visible-Light-Sensitive Hydrogen Release System.

Hydrogen boride (HB) sheet is a new class of 2D materials comprising hydrogen and boron, synthesized through ion-exchange and exfoliation techniques. HB sheets can release hydrogen (H) under light irradiation and is predicted to be a promising H storage material. However, its application is limited to the UV region. One approach to enable a visible-light-driven system is the utilization of plasmonic metallic nanoparticles. The present study reports H release from copper (Cu) nanoparticle-modified HB sheet (HB/Cu) under visible-light irradiation. Copper nanoparticles possess unique and strong plasmonic responses in the visible-light range, making them ideal light absorbers in this system. HB/Cu nanocomposites are synthesized using a simple mixture of copper acetate and HB sheets in acetonitrile, where HB sheets reduced copper ions to metal copper nanoparticles. The photoirradiation results shows that HB/Cu nanocomposites released more H than the bare HB sheets under visible-light irradiation. This is probably due to the plasmonic photothermal effect of copper metal, which enhances H generation from the HB sheets. This material offers a viable and cost-effective approach for developing visible-light-sensitive systems.