Tag Archives: Tata Institute of Fundamental Research (TIFR)

Climate change and black gold

A July 3, 2019 news item on Nanowerk describes research coming from India and South Korea where nano gold is turned into black nanogold (Note: A link has been removed),

One of the main cause of global warming is the increase in the atmospheric CO2 level. The main source of this CO2 is from the burning of fossil fuels (electricity, vehicles, industry and many more).

Researchers at TIFR [Tata Institute of Fundamental Research] have developed the solution phase synthesis of Dendritic Plasmonic Colloidosomes (DPCs) with varying interparticle distances between the gold Nanoparticles (AU NPs) using a cycle-by-cycle growth approach by optimizing the nucleation-growth step. These DPCs absorb the entire visible and near-infrared region of solar light, due to interparticle plasmonic coupling as well as the heterogeneity in the Au NP [gold nanoparticle] sizes, which transformed golden gold material to black gold (Chemical Science, “Plasmonic colloidosomes of black gold for solar energy harvesting and hotspots directed catalysis for CO2 to fuel conversion”).

A July 3, 2019 Tata Institute of Fundamental Research (TIFR) press release on EurekAlert, which originated the news item, provides more technical detail,

Black (nano)gold was able to catalyze CO2 to methane (fuel) conversion at atmospheric pressure and temperature, using solar energy. They also observed the significant effect of the plasmonic hotspots on the performance of these DPCs for the purification of seawater to drinkable water via steam generation, temperature jump assisted protein unfolding, oxidation of cinnamyl alcohol using pure oxygen as the oxidant, and hydrosilylation of aldehydes.

This was attributed to varying interparticle distances and particle sizes in these DPCs. The results indicate the synergistic effects of EM and thermal hotspots as well as hot electrons on DPCs performance. Thus, DPCs catalysts can effectively be utilized as Vis-NIR light photo-catalysts, and the design of new plasmonic nanocatalysts for a wide range of other chemical reactions may be possible using the concept of plasmonic coupling.

Raman thermometry and SERS (Surface-enhanced Raman Spectroscopy) provided information about the thermal and electromagnetic hotspots and local temperatures which was found to be dependent on the interparticle plasmonic coupling. The spatial distribution of the localized surface plasmon modes by STEM-EELS plasmon mapping confirmed the role of the interparticle distances in the SPR (Surface Plasmon Resonance) of the material.

Thus, in this work, by using the techniques of nanotechnology, the researchers transformed golden gold to black gold, by changing the size and gaps between gold nanoparticles. Similar to the real trees, which use CO2, sunlight and water to produce food, the developed black gold acts like an artificial tree that uses CO2, sunlight and water to produce fuel, which can be used to run our cars. Notably, black gold can also be used to convert sea water into drinkable water using the heat that black gold generates after it captures sunlight.

This work is a way forward to develop “Artificial Trees” which capture and convert CO2 to fuel and useful chemicals. Although at this stage, the production rate of fuel is low, in coming years, these challenges can be resolved. We may be able to convert CO2 to fuel using sunlight at atmospheric condition, at a commercially viable scale and CO2 may then become our main source of clean energy.

Here’s an image illustrating the work

Caption: Use of black gold can get us one step closer to combat climate change. Credit: Royal Society of Chemistry, Chemical Science

A July 3, 2019 Royal Society of Chemistry Highlight features more information about the research,

A “black” gold material has been developed to harvest sunlight, and then use the energy to turn carbon dioxide (CO2) into useful chemicals and fuel.

In addition to this, the material can also be used for applications including water purification, heating – and could help further research into new, efficient catalysts.

“In this work, by using the techniques of nanotechnology, we transformed golden gold to black gold, by simply changing the size and gaps between gold nanoparticles,” said Professor Vivek Polshettiwar from Tata Institute of Fundamental Research (TIFR) in India.

Tuning the size and gaps between gold nanoparticles created thermal and electromagnetic hotspots, which allowed the material to absorb the entire visible and near-infrared region of sunlight’s wavelength – making the gold “black”.

The team of researchers, from TIFR and Seoul National University in South Korea, then demonstrated that this captured energy could be used to combat climate change.

Professor Polshettiwar said: “It not only harvests solar energy but also captures and converts CO2 to methane (fuel). Synthesis and use of black gold for CO2-to-fuel conversion, which is reported for the first time, has the potential to resolve the global CO2 challenge.

“Now, like real trees which use CO2, sunlight and water to produce food, our developed black gold acts like an artificial tree to produce fuel – which we can use to run our cars,” he added.
Although production is low at this stage, Professor Polshettiwar (who was included in the RSC’s 175 Faces of Chemistry) believes that the commercially-viable conversion of CO2 to fuel at atmospheric conditions is possible in the coming years.

He said: “It’s the only goal of my life – to develop technology to capture and convert CO2 and combat climate change, by using the concepts of nanotechnology.”

Other experiments described in the Chemical Science paper demonstrate using black gold to efficiently convert sea water into drinkable water via steam generation.

It was also used for protein unfolding, alcohol oxidation, and aldehyde hydrosilylation: and the team believe their methodology could lead to novel and efficient catalysts for a range of chemical transformations.

Here’s a link to and a citation for the paper,

Plasmonic colloidosomes of black gold for solar energy harvesting and hotspots directed catalysis for CO2 to fuel conversion by Mahak Dhiman, Ayan Maity, Anirban Das, Rajesh Belgamwar, Bhagyashree Chalke, Yeonhee Lee, Kyunjong Sim, Jwa-Min Nam and Vivek Polshettiwar. Chem. Sci., 2019, Advance Article. DOI: 10.1039/C9SC02369K First published on July 3, 2019

This paper is freely available in the open access journal Chemical Science.

Functionalized nanomaterials for carbon capture

A few years ago I was at a breakfast hosted by a local member of the Canadian Parliament (Joyce Murray, Liberal, riding of Vancouver Quadra) and was unable to reply to a tablemate’s question about nanotechnology research in the area of carbon capture.  Since then I’ve stumbled across a few pieces of applicable research and hopefully someone will again ask me the question. In the meantime, some relevant recent work from India. From a May 9, 2016 news item on ScienceDaily,

Climate change due to excessive CO2 levels is one of the most serious problems humankind has ever faced. This has resulted in abrupt weather patterns such as flood and drought, which are extremely disruptive and detrimental to life, as we have been witnessing in India in recent years. Mitigating rising CO2 levels is of prime importance. In a new development, scientists at the Tata Institute of Fundamental Research, Mumbai, have developed a novel design of CO2 sorbents that show superior CO2 capture capacity and stability over conventional materials.

A May 9, 2016 Tata Institute of Fundamental Research press release on EurekAlert, which originated the news item, expands on the theme,

The immobilization of functional amines on a porous solid support can result in stable and efficient CO2 sorbent materials compared to similar liquid sorbents. A critical disadvantage however, is a drastic decrease in the textural properties of these supports (i.e., their surface area and pore volume), leading to a decrease in the CO2 capture capability.

To overcome this challenge, scientists at TIFR Mumbai, have designed novel functionalised nanomaterials that allows higher amine loading with a minimal decrease in surface area.

“Our fibrous nanosilica (KCC-1) should be a good candidate for use as a support to design efficient CO2 sorbents that would allow better capture capacity, kinetics and recylability”, says Dr Vivek Polshettiwar, the lead scientist of this study. A unique feature of KCC-1 is its high surface area, which originates from its fibrous morphology and not from its mesoporous channels (unlike in other well studied materials like SBA-15 or MCM-41). This study, published recently in the Journal of Materials Chemistry A, demonstrates the usefulness of the fibrous morphology of KCC-1 compared to conventional ordered mesoporous silica. This work is in continuation of the teams efforts to develop sustainable catalysts and sorbents.

The KCC-1-based sorbents showed several advantages over conventional silica-based sorbents, including i) high amine loading, ii) minimum reduction in surface area after functionalization and iii) more accessibility of the amine sites to enhance CO2 capture efficiency (i.e., capture capacity, kinetics and recyclability), due to the fibrous structure and high accessible surface area of KCC-1.

The demand for such efficient sorbents is on the rise since CO2 capture is one of the best solutions to mitigate the rising levels of CO2. Solid sorbents exhibit better efficiency with greater potential to overcome the shortcomings of liquid sorbents. The use of mesoporous silica materials functionalized with various amino groups is well reported. Although materials like SBA-15 and MCM-41, for example, have attracted significant attention because their large pore sizes can accommodate a variety of amine molecules and the high surface area allows for a higher loading of these functional molecules, they suffer from the disadvantages of a decrease in textural properties, thus making KCC-1 a suitable candidate for more efficient CO2 capture.

Here’s a link to and a citation for the paper,

Design of CO2 sorbents using functionalized fibrous nanosilica (KCC-1): insights into the effect of the silica morphology (KCC-1 vs. MCM-41) by Baljeet Singh and Vivek Polshettiwar. J. Mater. Chem. A, 2016,4, 7005-7019 DOI: 10.1039/C6TA01348A First published online 08 Mar 2016

I believe this paper is behind a paywall.