One Solution, Two Problems
Two major issues facing the world today are finding clean, affordable energy and disposing of waste in ways that don't cause harm to the environment. Climate change is making the clean, affordable, sustainable fuel problem more pertinent every day. A new study in Nature Energy has some suggestions on both scores, showing how natural light can be used to convert biomass into hydrogen.
Biomass has been used for energy and heat throughout history. Oil, as an example, is nothing more than a derivative of ancient biomass, transformed by the heat and pressure of the planet. Until now, lignocellulose — the main component of plant biomass — has been convertible into hydrogen only through a high temperature gasification process. This is mostly because lignocellulose plays an important role in providing structural stability in trees and plants.
Clean, Cheap Power
This new technology is based on a simple photocatalytic conversion process. The biomass is suspended in alkaline water, to which catalytic nanoparticles are added. The mixture is then exposed to light. The solution absorbs the light and produces gaseous hydrogen. The nanoparticles use the solar energy they absorb to catalyze complex chemical reactions, producing organic chemicals such as carbonate and formic acid as well as hydrogen. The hydrogen is collected at the top, free of substances like carbon monoxide, which makes it ideal for use as a power source.
This is a tremendous advance: although raw biomass is filled with chemical energy, it's unrefined — meaning it wouldn't work to power complex machinery. This new system bypasses this issue, using the power of the sun to transform the chemical energy in biomass into usable gaseous hydrogen. There are many ways to achieve the outcome, too: leaves, paper, and wood all worked in the system without any processing.