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 electrocatalysts 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, there still exists challenges in achieving high efficiency without resorting to expensive noble metal catalysts. HER electrocatalysts from transition metal-doped biomass are promising, cost efficient, durable and renewable alternative 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 (CNTs) by chemical vapor deposition which enhanced HER activity with overpotential reaching only 408 mV at a current density of −10 mA cm⁻², an increase in performance by 30% when compared to that of 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.