The Environmental Engineering Hub

There's a lot of promise behind the biological fuel cells, which normally use an organic fuel, like methanol or ethanol. In these cases, it is the enzymes, instead of conventional chemical catalysts like platinum, that help speed up the electrode reactions. These Fuel Cells attempt to copy nature in a way that energy is obtained from organic fuels. However, these fuel cells are not anywhere near to becoming commercial applications. Reference: LARMINIE, James; DICKS, Andrew. Fuel Cell Systems Explained. 2. ed. West Sussex, England: Wiley & Sons Ltd., 2003. 418 p.

Hydrogen reacts at the anode and releases energy. However, that doesn't mean that the reaction proceeds at an unlimited rate just because energy is liberated. Activation energy must be involved so that the process can get over the "energy hill". If the probability of a molecule having sufficient energy is low, then the reaction won't proceed at normal speeds. This is the case for fuel cell reactions, with the exception of situations which involve high temperatures. The 3 best known ways of dealing with slow reaction rates are: the use of catalysts, increasing the electrode area and raising the temperature. The first two solutions can be employed to any chemical reaction. The third, however, is present in fuel cells only. When considering the following reaction 2H 2 + 4OH - → 4H 2 O + 4e - It can be noticed that fuel gas and OH- ions coming from the electrolyte need to be present alongside the activation energy. Additionally, the "meeting" betw

The basic functioning of a hydrogen fuel cell (FC) is simple. One way of looking at it is to say that the hydrogen is burned or combusted as according to the following reaction:                                                                        2H 2 + O 2 → 2H 2 O However, instead of heat energy being produced, it is electrical energy that is released. At the anode of an acid electrolyte FC, the hydrogen gas suffers ionization, liberating electrons and creating H+ ions (protons):                                                                        2H 2 → 4H + + 4e - Where energy is released from that reaction. In the cathode, oxygen reacts with electrons that are taken from the electrode, and protons from the electrolyte, to generate water.                                                                  O 2 + 4e - + 4H + → 2H 2 O For the reaction to continue, electrons generated at the anode have to pass through an electrical circuit to the ca

The environmental problems that come from the utilization of fossil fuels are a great reason for the future implementation, in large scale, of different energetic matrices. Hydrogen is one of the most promising options, being the theme of intense scientific investigation geared towards a "Hydrogen Economy", a world scenario which consists of having hydrogen and electricity as its protagonists. The hydrogen gas can be obtained through different processes, among some one can point out the electrolysis and the natural gas reformation, with the last one being responsible for over 48% of such worldwide production. The reformation of natural gas has, as an advantage, its low cost, but the hydrogen produced by that process has high levels of carbon monoxide contamination, which is a limiting factor for some applications. The most efficient and cleanest form of extracting electrical energy from hydrogen is through fuel cells (FCs). Differently from internal combustion mach