Scientists at the Centre for Nano and Soft Matter Sciences (CeNS) have developed a nickel oxide-based urea. Urea electrolysis is helpful in urea-based waste treatment with low-cost hydrogen production, which, in turn, can be used for energy production.

The energy requirement for hydrogen production through water electrolysis can be reduced by 70 per cent through urea electrolysis. The energy-intensive counterpart of water splitting, oxygen evolution, can be replaced with urea oxidation in urea electrolysis. The low-cost, earth-abundant nickel-based catalysts are widely applied for this process. The main challenge associated with urea oxidation is ensuring the sustained activity of the catalyst as the strong adsorption of the reactive intermediate, referred to as catalyst poisoning, causes activity loss.

CeNS researchers Alex C, Gaurav Shukla, Muhammed Safeer and Neena S John explored electrocatalysts and used high-energy electron beams to produce surface defective unsaturated nickel sites in nickel oxide.

They say this is an effective way to produce a large number of coordinatively unsaturated active sites on electrocatalysts. It was observed that these generated sites effectively adsorb urea and this favours the direct urea electro-oxidation mechanism.

India is one of the top countries by urea production — 244.55 lakh tonnes in 2019-20. The nitrogenous fertiliser industries generate a high concentration of ammonia and urea as effluents. This can be utilised for energy production.

Artificial brain for pattern recognition

Artificial neural networks (ANNs) — a system of interconnected electric circuits or algorithms that communicate with one another just like the neurons in our brain — are gaining popularity for their ability to perform complex tasks, especially in pattern recognition. However, existing devices that mimic neurons and synapses — the junction between two interacting neurons — operate at high voltages and show variable conductivity, making it difficult to construct efficient ANNs.

To address these concerns, researchers at the Indian Institute of Science (IISc), Bengaluru, have developed an indium selenide-based transistor, which was found to mimic several characteristics of a biological synapse, says a write-up in Kernel, an in-house magazine published by the institute.

The team, led by Digbijoy Nath, at the Centre for Nano Science and Engineering (CeNSE), fabricated a transistor out of multi-layered indium selenide, and tested its response to sequential voltage pulses, similar to the electric signals in neurons.

The output characteristics of the device were able to capture essential features of the synapse, says the Kernel article. The researchers also used the device’s responses to build a computer model that simulated an ANN. When they trained the ANN with a database of handwritten numbers, it was able to recognise 93 per cent of the numbers correctly. This device shows promise in constructing more complex neural networks for pattern recognition.

Solid adsorbents for carbon dioxide capture

A group headed by Rahul Banerjee at IISER-Kolkata has demonstrated a strategy to synthesise novel solid adsorbents, especially for carbon dioxide capture and utilisation. Prof Banerjee’s group has discovered special types of nanoparticles or microparticles that can capture carbon dioxide in their pores.

The novel materials with distinct physical properties on their surface that have been synthesised include porous ‘covalent organic frameworks’ (like COF-graphene Janus thin films), porous covalent bonded organic nanotubes and COF-coated zeolite.

The judicious choice of 2D graphene sheets as a grafter helped the researchers design and create COF-graphene Janus thin films through the interactions (non-covalent) between the COF and graphene, rendering flexible porous Janus films at the DCM-water interface. “The newly designed COF-coated zeolites could be an excellent candidate for carbon dioxide storage in the industry due to their high surface area and increased chemical stability,” says a press release.

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