Composites of Co-Al hydrotalcites and carbon nanomaterials for photocatalytic H2 production

Abstract

Hydrogen is considered one of the main energy sources for the near future. Numerous efforts are currently underway for the direct transformation of solar energy into H2. Hydrotalcites are two-dimensional materials whose composition can be tuned relatively easily and, by themselves or in combination with other materials, are proving to be useful for the H2 evolution reaction. In this work, composites of a Co-Al hydrotalcite with carbon microspheres or nanotubes have been prepared. It has been shown that, in general, such composites improve H2 production. The influence of the nature, structure, and characteristics of the different materials on the reaction has been studied, as well as the role of each component and its mechanism. In particular, proper integration of both components and improved textural properties, as is the case of the composite with carbon microspheres, leads to a yield of 3820 µmol H2 g-1 at 5 h, more than twice that obtained with hydrotalcite alone, in the presence of Ru(bpy)3Cl2 as a photosensitizer and triethanolamine as an electron donor at 450 nm. The present methodology opens the door to the preparation of other composites for the improvement of the performance of photocatalytic systems for H2 production.