Diamond and Metal Photo-Electrocatalysts for Hydrogen Evolution and Carbon Dioxide Reduction

Project Information

DIMPEL CAT

Grant agreement ID: 895388

DOI

10.3030/895388

Project closed

EC signature date 11 March 2020

Start date 1 January 2021

End date 31 December 2022

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 224 933,76

EU contribution

€ 224 933,76

Coordinated by

UNIVERSITY COLLEGE LONDON
United Kingdom

Periodic Reporting for period 1 - DIMPEL CAT (Diamond and Metal Photo-Electrocatalysts for Hydrogen Evolution and Carbon Dioxide Reduction)

Reporting period: 2021-01-01 to 2022-12-31

Summary of the context and overall objectives of the project

Climate change, increased energy demand, and greenhouse gases have major impacts on the environment. Following the recent International Climate Change conferences in Paris and Glasgow, many nations have initiated measures to fulfil their agreements to reduce carbon emissions and promote renewable energy. In addition, EU Horizon 2020 has the major priority to invest funds in development of secure, clean and efficient energy methods. In particular, greenhouse gases have major impacts on the environment which has led researchers to find alternative sustainable energy sources (e.g. hydrogen), and ways to convert greenhouse gases such as carbon dioxide to valuable chemicals. Therefore, there is a strong incentive to develop alternative, sustainable catalysts based on cheap, earth abundant materials.
The material developed in this action and in the long term (more than 10 years) will help in recycling carbon dioxide to other useful chemicals and production of hydrogen at ambient conditions. This will further help in reaching net-zero carbon emissions, the target set by several countries, and also the European Union. This project further decreases the cost of the use of expensive metals such as platinum, and complexes containing ruthenium, a rare earth metal, which requires high energy mining and purification methods while deeply affecting natural habitats and the environment.
In this project, we explored the use of diamonds as nano materials which can release electrons into solution upon illumination; the electrons can be used by transition metal complexes tethered on the diamond surface for the production of hydrogen and to convert carbon dioxide into valuable chemicals such as CO and formic acid. This project had two major research objectives: (i) To develop novel catalysts with diamonds and transition metal complexes (TMCs) as photo- and electro- catalysts for hydrogen evolution and carbon dioxide reduction. (ii) To get deep understanding of the functioning and degradation of these catalysts through mechanistic studies.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The major objective of this proposal is successfully achieved which is CO2 reduction and H2 evolution under ambient conditions. We have synthesized five transition metal complexes, also electroplated manganese and cerium oxides onto diamond and tested these for CO2 reduction activity. The newly synthesized complexes were attached to the boron-doped diamond plates and tested for H2 evolution and CO2 reduction. Further, mechanistic studies (objective 2) were performed using set of advanced spectroscopic techniques, such as in situ infrared spectroscopy. Important achievements were the observation of selective CO2 reduction under the reaction conditions to acetic acid, by using diamond and manganese oxide deposited electrochemically under thin layer conditions.
In parallel, to understand the photochemistry of the diamond modified surfaces, we have built a spectrometer from scratch in collaboration with Dr Michael Parkes at UCL, and several experiments were conducted to understand the solvated electrons that can be formed during the photo electrochemical conditions, a great deal of progress was made to build the spectrometer from scratch, and initial results of the photocurrents were obtained. Future experiments are planned and going to be carried out with advance transient tools from the basic setup and design on an advance Transient Absorption Spectroscopy (TAS) setup at the Advanced Laser Facility at UCL.
In summary we have successfully performed synthesis of transition metal complexes that have amine groups that can be easily attached to the diamonds surface. Successful deposition of various metal oxide and hydroxides were performed on the electrodes and these were tested for hydrogen generation and CO2 reduction in aqueous solutions. The research was heavily hampered by the combination of Brexit and Covid-19 international pandemic at the starting of the project. Nevertheless, excellent progress was made towards the research goals and one paper is in final stage of revision, one soon to be submitted, and more in preparation.
MCIF has disseminated the results to a broad scientific community by participating in conferences, meetings, and seminars. A draft of the key results from manganese oxide with and other experiments with diamond modification has been made and under submission. Further a news article was released in UCL department of Chemistry Newsletter where he has explained about past and future endeavours along with a glimpse of his motivation for the work at UCL. A personal website was made where he has updated his scientific activities and future goals. All dissemination activities undertaken where acknowledged by EU funding. As well as any publications in future resulting from this funding will be acknowledged with EU funding, will be open access and uploaded on the UCL publications repository.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

This proposal involves for the first-time combination of transition metal complexes with electrons from diamonds for hydrogen evolution and carbon dioxide reduction. DIMPEL CAT has brought together two important breakthroughs in photo and electro catalysis field . The major outcomes here are CO2 reduction testing in aqueous conditions, less catalyst loading, and more reactants for reduction. Here, we have attached several transition metal complexes to the diamond, also tested hydroxyl group termination and further amine groups on diamonds under photo electrocatalytic conditions in CO2 reduction and H2 evolution. We have explored for the first-time diamond modified with manganese oxides and employed it in CO2 reduction using the diamond and manganese oxide combination and the results has shown significant selectivity in CO2 reduction, and we have investigated in-depth mechanistic studies to understand the catalysts behaviour during reduction conditions, which was beyond the state of art.
The major scientific impact is that the results obtained are in the field of diamond and transition metal complexes by attaching the later ones to the surface of diamonds, and able to obtain products such as acetone, acetic acid, CO. We also majorly achieved the selectivity with fine control on the conditions, in depth mechanistic studies and most importantly in aqueous conditions. In future high surface diamonds surface were planned with the current deposition methods from DIMPEL CAT both to increase the catalyst loading by multiple folds and obtain products with great selectivity. Another important point to note is that diamond’s stability under saline conditions means it can be exploited as an electrode material for generation of green hydrogen from saline waters. Ultimately this would help in reducing the dependencies on the petroleum-based products and to use sustainable resources for future energy needs. Additionally, diamonds are far less toxic compared to quantum dots and synthetically highly feasible, highly sustainable (mostly carbon) to have clean and sustainable production of valuable fuels such as H2 or CO or formic acid. This research has another major scope to extend further in direction of nitrogen reduction to form ammonia, which is highly important, and currently the process is highly energy demanding. The outcomes of this proposal so far has contributed in development of novel catalysts and mechanistic studies which comes under Sustainable Energy field and the goals of EU Horizon 2020.

Microscope and raman spectra of diamond modified with managnese oxide

diamond modified with transition metal complex under catalytic studies

Diamond with transition metals