Research Motivation
Large scale ammonia production is done using the energy-intensive Haber-Bosch process. The whole process results in the consumption of ~2% of worldwide fossil fuels and emission of about 1.4% of worldwide CO2, annually. Population-based predictions indicate that the market size for ammonia in 2050 will increase from 175 to between 220 and 402 million tons, resulting in the emission of between 640-1170 million tons per year of anthropogenic CO2-eq. Photocatalytic ammonia synthesis is an emerging zero carbon emission technology. However, the adsorption and activation of the N2 molecule on the photocatalyst surface is a great challenge due to its intrinsically inert properties, which makes the protonation, oxidation and reduction of this molecule very difficult. To boost the efficiency of the photocatalytic ammonia synthesis, highly active photocatalyst should be designed.
Layered-double-hydroxide (LDH) materials are attractive candidates for the study of N2 reduction to ammonia due to their tunable metal ions in a wide range without altering their structure, which allows the introduction of different surface dopants.
Project Assumptions
Supporting LDH nano-sheets (NS) on the surface of metal oxides enhances the charge transfer properties, resulting in better photocatalytic efficiency. The metal oxide acts as a Lewis-acid, trapping the excited electrons, leading to better charge separation.
Project Goal
Overall goal: Catalyze the N2 reduction to ammonia using layered-double-hydroxide nano-sheets supported on different metal oxide supports.
Sub-goals:
1) Study the effect of photo-catalytically active support (e.g. TiO2).
2) Study the effect of non-photo-catalytically active support (e.g. SiO2).
3) Study the effect of two different dopants.
4) Study the effect of 3 different dopant concentrations.
5) Compare the activity of supported LDH-NS vs unsupported NS.
Methodology:
1) LDH synthesis via co-precipitation in the presence of MO2.
2) Calcination of the precipitate at elevated temperature to obtain mixed oxides grafted on the MO2 surface.
3) Characterization of the obtained materials to confirm the formation of LDH and interaction with the support.
4) Studying the photocatalytic activity by in-situ FTIR measurements.
Student Tasks:
1) Synthesize LDH according to a given procedure with different dopant concentrations and in the presence of different metal oxide types.
2) Calcine the obtained powder in a calcination furnace.
3) Run in-situ FTIR measurements according to a given procedure.
4) Analyze the results.
5) Write a final report with all findings.
6) Prepare a presentation and present the results in front of the supervisor and other colleagues.
Expected outcomes:
By the end of the internship period the student will achieve the following skills/outcomes:
1) Brief introduction regarding the work in an experimental research lab.
2) Brief introduction to the field of photocatalysis.
3) Learn how to synthesize LDH.
4) Learn several characterization methods, most notably in situ FTIR spectroscopy.
5) Improve writing and presentation skills.
