Page 59 - Annual Report_21-22

Chemosensor for selective and sensitive detection of water in organic solvents.

Detection of water impurities in various chemical be an alternative to various conventional methods such
environments finds its significance in process control of as the gravimetric weight-loss method and Karl-Fischer
various industrial applications, environmental impact titration method. The chemosensor undergoes dual mode
evaluation and physiological assessment in the biomedical photophysical signalling along with colour transition in
domain. Therefore, the detection and content estimation the selective presence of water content in 1,4-dioxane
of water when present in traces is highly desirable, as those with a capability of 0.013 (% v/v) detection sensitivity.
influence the physiological stability of drugs, catalyzes The water detection efficacy of the chemosensory probe
various chemical reactions, and vastly manipulate the was demonstrated in a three channel multi-helical micro-
manufacturing and production of the industrial domain. fluidic mixture system. The development of a lab-on-a-
In this endeavour, a chemosensor methodology could be chip device is under process for the detection of water in
developed for convenient detection and determination of organic solvents for industrial applications
water content in organic solvents, which were found to

Figure: The photophysical signaling with a rhodamine-6G based bis-fluorophoric probe demonstrates
detection of water impurities in organic solvents.

Concerted effect of Ni-in and S-out on ReS nanostructures towards high-efficiency oxygen
2
evolution reaction
Hydrogen has been increased significant attention to boost high faradaic efficiency of 96 %, benefiting from the rapid
green and sustainable energy growth as an alternative to charge transfer caused by the concerted effect of Ni-in and
fossil fuel and cumulatively severe environmental pollution S-out on ReS nanostructure (Figure 1). This work provides
2
problems. Water electrolysis is considered promising, a highly effective and stable electrocatalyst for OER
eco-friendly, and one of the best ways to produce applications and opens up a promising and straightforward
hydrogen. It has two complementary half-reactions, i.e., strategy to develop catalysts for other applications.
hydrogen evolution reaction (HER) at the cathode and
oxygen evolution reaction (OER) at the anode. However,
the efficiency of the overall water splitting process gets
circumscribed by the sluggish kinetics of OER being a
complicated multistep four-electron transfer process.
Therefore, catalysts are needed to increase the reaction
rate and lower the overpotentials towards OER. Ru and
Ir-based materials are currently the benchmark catalyst
for OER reaction but their shortage and high-cost limit
for the commercialization and industrial production. So,
it is necessary to develop an electrocatalyst of abundant
elements with high activity and durability with at a
low cost. Herein, a one-step hydrothermal reaction is
developed to synthesize Ni-doped ReS2 nanostructure
with the sulphur defect. The material exhibited excellent Figure: Scheme showing the concerted effect of Ni-in and
OER activity with a current density of 10 mAcm at an S-out on ReS2 nanostructures towards OER
-2
overpotential of 270 mV, a low Tafel slope of 31 mV/dec,
good long-term durability of 10 h in 1 M KOH. It shows

ANNUAL REPORT 2021-22 57