Research Rituraj Borah

Abstract

Conventional electrolyzers for green hydrogen production comprise membranes or dividers that add to the overall complexity, cost, and maintenance of such systems. In addition, they impose stringent water purity requirements, while fresh water is (becoming a) scarce resource. As a solution, I propose an alternative reactor design that is simpler, robust and more cost-effective. Specifically, in this project I will study a membraneless photo-electrolyzer that produces hydrogen gas from (sea)water, solar light and/or renewable electricity sources. This new cell design is based on flow-mediated separation of the hydrogen and oxygen gas evolving from the photo-electrodes. This concept has recently been patented by the applicant. First advances will be made at the level of the photo-electrodes, by applying nanostructuring of the surface to decrease the bubble size, which in turn will favor gas separation and product purity (set at 99.5%). Secondly, for efficient photo-electrolysis, new optical enhancement mechanisms will be studied to push the solar-to-hydrogen efficiency towards the 10% target. Finally, to exploit the robustness of the cell design, the aim is to demonstrate the cell operation for both electrolysis and photo-electrolysis of sea-water through careful understanding of the crucial process parameters (e.g. pH).

Researcher(s)

• Promoter: Verbruggen Sammy
• Co-promoter: De Wael Karolien
• Fellow: Borah Rituraj

Research team(s)

• Antwerp engineering, PhotoElectroChemistry & Sensing (A-PECS)

Project type(s)

• Research Project

Abstract

The conventional electrolyzer technologies for hydrogen production are based on a membrane or divider that keeps the H2 and O2 gases evolving from the electrodes separate while allowing the ionic currents to flow. Due to the complexity and high costs of these systems, an alternative electrolyzer design that is simpler and cheaper is a technological need of the moment. Also for photo-electrolyzers (or photoelectrochemical cells) to produce H2 from water under sunlight, a simple membraneless design is very important for scaling up to large scale. Besides, in many electrolytic processes such as chlor-alkali, glycerol oxidation, etc., a membraneless cell design can significantly improve the existing challenges with membrane failure, maintenance difficulty and so on. In view of these challenges as well as the opportunities for technological/scientific advancements, the current project aims at the development of a membraneless (photo)electrolyzer cell that promises to solve the existing problems. This proposal is based on the initial validation of the working principle of this new designs by CFD simulations, fluid flow and electrochemical experiments. These initial findings also resulted in a patent filing (Borah et al., patent application number: EP22177270.0). The objective of this project is the further development of this cell design for electrolysis, photo-electrolysys (unbiased) and other photoelectrochemical processes. Thus, the completion of the experimental set-up that the budget is motivated towards will enable exploration of not only (photo)electrochemical water splitting, but also sea-water splitting, chlor-alkali and glycerol oxidation. The project complements the expertise of the applicant on the fabrication of nanostructured self-assembled films which will be useful for electrode/photoelectrode development. Both the (photo)electrolyzer cell design and photoelectrode development are also supported by the applicant's expertise in computational fluid dynamics and computational electromagnetic modeling. This project enables the applicant to create a new line of research based on a membraneless (photo)electrochemical cell (or (photo)electrolyzer) to explore important photoelectrochemical processes including water electrolysis. The applicant creates new opportunities to do impactful research and explore new topics building upon his existing expertise.

Researcher(s)

• Promoter: Borah Rituraj

Research team(s)

Project type(s)

• Research Project

Abstract

Functional nanostructures are one of the most promising class of materials for the remediation of the present environmental/humanitarian problems of the world. Functional nanostructures or nanoparticles are basically the smallest units that posses a specific functionality according to the intended application. For the application of such nanoparticles at large scale, it is also important to order them starting from nanoscale to the macro scale. Self-assembly is one promising strategy to assemble nanoparticles to form films, clusters or bulk materials with nanoscale order. This project aims to provide a cheap technology for the fabrication self-assembled films (or even bulk materials) for energy/sensing/medical related applications depending upon the functionality of the nanoparticles. This new technology is an advancement on the already existing technology but with some innovative twists that reduces the cost significantly. With this proposed set-up, one can obtain self-assembled films of nanoparticles at a much lower cost relative to the existing commercial set-ups for applications such as air/water purification reactors, solar cells, sensing platforms, etc.

Researcher(s)

• Promoter: Borah Rituraj

Research team(s)

Project type(s)

• Research Project

Abstract

Soot is considered to be the second-largest contributor to global excess radiative forcing after CO2 and deemed responsible for tripling the amount of premature deaths by 2060. We therefore propose a fundamental study to develop an efficient photocatalyst for the degradation of soot deposits, using (solar) light as the energy input. Photocatalytic oxidation is often achieved with TiO2 as the photoactive material. The main drawback of TiO2 is its large band gap, which limits the overall solar light response to the UV region of the spectrum. As a solution, plasmonic photocatalysis using noble metal nanoparticles (NPs) has emerged as a promising technology to expand the activity window of traditional photocatalysts to the entire UV-visible light region of the solar spectrum. In this project gold and silver NPs will be merged to overcome their individual limitations and form stable bimetallic NPs with highly tunable plasmonic properties over a wide wavelength range. These bimetallic NPs will be organized as an ordered plasmonic nanostructure, that will be characterized from bulk to nanoscale, a part of which in collaboration with the Institute for Catalysis at Hokkaido University, Japan. The effect of plasmonic enhancement on the photocatalytic soot degradation mechanism will be studied on a fundamental level by in-situ FTIR spectroscopy, but also through larger scale demonstration experiments that illustrate the relevance of this research to the broader audience.

Researcher(s)

• Promoter: Verbruggen Sammy
• Fellow: Borah Rituraj

Research team(s)

Project type(s)

• Research Project