Solar-driven electrocatalytic formation of hydrogen and syngas for downstream catalytic hydrogenation and hydroformylation reactions

The aim of this thesis is to use solar driven electrocatalysis to produce hydrogen and hydrogen/carbon monoxide from water and water/carbon dioxide, respectively, to support downstream production of useful chemicals using catalytic hydrogenation and hydroformylation. Metal and metal phosphide electrocatalysts were investigated for the electrochemical reduction of CO2 and water into CO and hydrogen, respectively. For the hydrogen evolution reaction, iron phosphide was prepared using two different methods: electroplating and spray-pyrolysis on carbon cloth (FeP/C). The catalytic activities of the two FeP/CC electrocatalysts were compared in terms of overpotential, Tafel slopes, stability and durability in acidic and neutral media. Both electrocatalysts were able to produce H2 at a sufficient rate to support hydrogenation at room temperature and pressure.
Copper and copper phosphide electrocatalysts were used for the CO2 reduction reaction. Copper based electrocatalyst were either based on Cu foils (commercial) or prepared by a novel 3D printing methodology followed by phosphidation. The electrochemical reduction of CO2 using Cu3P favoured proton reduction over CO2 reduction. The water oxidation reaction occurred at a carbon plate in acidic media or using cobalt/phosphate (CoPi) on stainless steel in neutral media.
The electrocatalysts were used as part of a home built proof-of-principle solar powered reactor. The reactor was used to couple the electrocatalytic reactions with downstream catalytic reactions operating at room temperature and pressure.