Materials and molecules for pollution free clean energy
- Autores: Yuanyuan Shi
- Directores de la Tesis: Antoni Llobet Dalmases (dir. tes.), Mario Lanza Martinez (codir. tes.)
- Lectura: En la Universitat Rovira i Virgili ( España ) en 2018
- Idioma: español
- Tribunal Calificador de la Tesis: Stefania Maria Serena Privitera (presid.), Xavier Sala Román (secret.), Fernando Bozoglián (voc.)
- Programa de doctorado: Programa de Doctorado en Nanociencia, Materiales e Ingeniería Química por la Universidad Rovira i Virgili
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
The combustion of fossil fuels produces a myriad of toxic air pollutants and carbon dioxide, which is significant greenhouse gas and changes our climate. These emissions have been the most significant threat to globally environmental problems, which influence the health and future of the whole human society. Except for the air pollution and climate change from consumption of fossil fuels, these fossil fuels are formed from the remains of the living plants and animals that lived millions of years ago, which are not renewable energy sources. The BP statistical Review of World Energy 2016 has calculated how long it leaves until all the fossil fuels reserves run out based on the known reserves and annual production levels in 2015. The reserves-to-product ratio shows that the global coal will run out in 115 years, however the oil and natural gas remaining will run out in ~50 years,respectively.19 In order to build a sustainable future for next generations, the human activities should become less dependent on the fossil fuels, and the study of renewable and clean energy has been investigated to let it become the major energy provider for the next century. The US Energy Information Administration predicts that around half of the world energy consumption will come from renewables by the early 2040s. As one of the main renewable energy sources (wind, hydropower, solar, etc.), solar energy plays a very important role in the development of renewables, since sunlight is decentralized and inexhaustible in the world. Moreover, the Earth’s surface can receive ~ 1.2 × 10E14 kJ solar energy per second.
With the motivation to make our contribution to improving the globally environmental and energy problems, in this PhD thesis I carried out an investigation about of airbone pollutants, and then peformed the exploration of novel materials and molecules for pollution free clean energy, which maily focused on solar energy converted hydrogen through water splitting in this thesis. During the past years investigation, I have learned how to grow thin but high quality metal/metal oxide thin films through physical vapor depositions, such as sputtering, e-beam evaporation and atomic layer deposition (ALD). I have learned how to built the configurations for various solar-driven water splitting devices. The (photo)electrochemical analysis is one of the most important characterization methods in my research, and I have gained lots of experiences form this basic analysis to understand my metal oxides or molecular catalysts better. I have also learned how to perform a series of morphological/topographical, electrical, mechanical and chemical characterizations at nanoscale/microscale through atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS).
In this first part of my thesis, I have statistically analyzed more than 500 airbone pollutant particles, PM2.5 particles, which were in situ collected from polluted air. I decided to study the PM2.5 particles because they are very small which can invade even the smallest airways and penetrate to the lungs. From my stduy we can draw the following conclusions:
• The PM2.5 particles mainly show three main shapes, which are fluffy soot aggregates, elongated minerals, and spherical fly ash. The soot aggregates are rich in carbon, whcih are mainly from incomplete combustion of hydrocarbons. The elongated minerals are with high content of metals from coal-fired power plants. And the spherical fly ash is mainly made of metal silicates from road dust, construction, coal combustion and secondary atmospheric reactions.
• The carbon-rich fluffy soot aggregates are always more unstable and much stickier, which show very high adhesiveness and aggregation. This result indicates the soot aggregates can be more toxic/dangerous for the human bodies.
• More than 50% PM2.5 particels strongly interact with the substrate through a ultran thin (< 10 nm) dark trace layer. The statiscal analysis shows that this dark trace layer is very stable even under mechanical stress and it is consisted of alkali metals, hydrogen and CH groups. This result may provide new ideas to remove the PM2.5 particels in our body from biomedical views.
