Nanostructured Materials for Advanced Energy Conversion and Storage Devices: Safety Implications at End-of-Life Disposal

Abstract

The global demand for electricity has gradually increased to 20,000 TWh in 2016 at approximately 2% per decade. The top four resources to generate electricity are coal, natural gas, nuclear, and renewables. In the USA, natural gas has displaced coal as the primary source for the generation of electricity. In the transport sector, fossil fuels dominate. The two major drawbacks of using fossil fuels for energy and transport are the harmful emission of oxides of carbon, nitrogen, and sulfur and the limited availability of these resources if measured in centuries rather than years. To offset these short- and long-term problems, researchers have proposed the development of fuel cells (FCs) as a potential solution. The FCs convert fuels (such as hydrogen) into water and electricity with zero or near-zero emission of harmful gases. Hydrogen is generated using either water splitting or steam reformation of methane, coal gasification, or from methanol. The above alternative solutions require chemical and electrical energy and are not necessarily carbon dioxide neutral. To improve the efficiency and lower the cost of the fuel cell stack, researchers have focused on replacement of platinum anode/cathodes with other non-precious metals. Their potential toxicity and interactions with the environment, animals, and people have received little attention, unlike our understanding of the toxicity of gasoline volatiles, particulate matter, and organic residues. In this study, we evaluated the potential biological effects using core-shelled Fe3O4 magnetic nanoparticles (MNPs) as an example. The toxicity results indicate that electrocatalyst with appropriate structural support may be biologically benign. The toxicity of these catalysts may be an issue in the near future since the number of electric and hydrogen-powered automobiles with fuel cells is expected to increase. This increased utilization will lower consumption of fossil fuels, as well as emission of greenhouses gases, but will increase a secondary risk of the effects of these electrocatalysts. Our results demonstrate the minimization of oxidative stress and cellular damage if encapsulated with natural product extracts.