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In this thesis, we will focus on the solvothermal synthesis of iron phosphides (FeP, Fe2P) using triphenylphosphine (TPP) as an inexpensive and stable phosphorus source. The obtained iron phosphides were applied as electrocatalysts in hydrogen evolution reaction (HER), oxygen evolution reaction (OER), Rhodamine B (RhB) degradation, Escherichia coli (E. coli) inactivation, nitrates reduction reaction (NO3RR) to ammonia (NH3), and as counter electrodes in dye-sensitized solar cells (DSSCs). Detailed characterizations of catalysts were carried out to investigate the correlations between the material structure and catalytic activity. The first part of the thesis gives an introduction to the topic which cover overview of literature about the use of transition metal phosphide as efficient electrocatalysts in water splitting studies, NO3RR to NH3 and DSSCs. The second part is a description of the experimental methods. The third part discusses the solvothermal synthesis of FeP and Fe2P catalysts using TPP precursor. The phase conversion of iron phosphides at elevated temperatures under reductive atmosphere was reported. Structural characterizations of the obtained materials were achieved using multiple techniques. The electrocatalytic activities of heat-treated iron phosphide films for HER were studied in acidic environment. The fourth part discusses the use of Fe2P nanoparticles (NPs) for OER. The fifth part outlines the use of Fe2P precatalyst in water treatment studies. Using a thin film of Fe2P precatalyst, RhB degradation and E. coli inactivation in the presence of in-situ generated reactive chlorine species were reported. Characterization of Fe2P electrocatalysts before and after the test was carried out using different techniques. The sixth part shows for the first time the use of FeP and Fe2P as a noble metal-free electrocatalysts for NO3RR to NH3. In this chapter we will emphasize the nitrate reaction pathways, which are highly complex and poorly understood. The seventh part demonstrates the use of FeP and Fe2P catalysts as robust and efficient counter electrodes in DSSCs. V diplomskem delu se bomo osredotočili na solvotermično sintezo železovih fosfidov (FeP,Fe2P) z uporabo trifenilfosfina (TPP) kot poceni vira fosforja. Pripravljene železove fosfide smo uporabili kot elektrokatalizatorje za evolucijo vodika (ang. HER – hydrogen evolution reaction), evolucijo kisika (ang. OER- oxygen evolution reaction), razgradnjo barvila Rhodamine B (RhB), inaktivacijo bakterij Escherichia coli (E. coli), redukcijo nitratov (NO3RR) v amoniak (NH3) in kot elektrode v sončnih celicah, kot so organske in barvno občutljive sončne celice (DSSC, ang. dye-sensitized solar cells). Korelacije med strukturo materiala in katalitično aktivnostjo smo dobili s primerjavo različnih tehnik karakterizacije. Prvi del diplomske naloge predstavlja uvod v temo, ki zajema pregled literature o uporabi fosfida prehodne kovine kot učinkovitih elektrokatalizatorjev pri študijah cepitve vode, NO3RR v NH3 in DSSC. Drugi del je opis eksperimentalnih metod. Tretji del obravnava solvotermično sintezo FeP in Fe2P katalizatorjev z uporabo prekurzorja TPP. Proučevali smo fazne transformacije v železovih fosfidih pri povišanih temperaturah v reduktivni atmosferi. Strukturne karakterizacije pridobljenih materialov so bile dosežene z več tehnikami. Preučevali smo elektrokatalitične aktivnosti toplotno obdelanih filmov železovega fosfida za HER. Četrti del zajema uporabo nanodelcev Fe2P (NP) za OER. Peti del opisuje študije za uporabe katalizatorja Fe2P za namen čiščenja vode. Z uporabo tankega filma katalizatorja Fe2P smo dokazali učinkovitost pri razgradnji RhB in inaktivaciji E. coli v prisotnosti interno nastale hipoklorne kisline. Karakterizacija Fe2P elektrokatalizatorjev pred in po testu je bila izvedena z različnimi tehnikami. V šestem delu je prvič prikazana uporaba elektrokatalizatorjev FeP in Fe2P za redukcijo nitratov v NH3. V tem poglavju bomo obdelali reakcijske mehanismi za sintezo amoniaka, ki so zelo zapletene in slabo razumljene. Sedmi del prikazuje in obravnava uporabo FeP in Fe2P katalizatorjev kot elektrod v DSSC. |
