Boosting Hydrogen Production with Raspberry-Derived Carbon Aerogels with In-Situ Grown Carbon Nanotubes

Abstract

This study explores the use of biomass-based carbon aerogels from raspberry pulp as electrocatalyst for the hydrogen evolution reaction (HER). Producing hydrogen via alkaline water electrolysis, from renewable energy sources, is an attractive way to mitigate climate change, however it still presents challenges in achieving high efficiency without resorting to expensive noble metal catalysts. HER electrocatalysts obtained from metal-doped biomass present a promising alternative for cost efficient, durable and renewable materials. Freeze dried raspberry pulp with added iron salts was pyrolyzed, resulting in carbon aerogels containing iron oxide nanoparticles. These nanoparticles were later used to grow carbon nanotubes (CNT) by chemical vapor deposition which enhanced HER activity reaching an overpotential of only 408 mV at a current density of -10 mA cm^-2, an increase in performance by 30% when compared to aerogels without CNTs. This shows that our synthetic approach is effective for catalysis applications, and its versatility means that efficiency could be improved further by tuning the properties of iron oxide nanoparticles and the three-dimensional interconnected porous network of the carbon aerogel.