@article { ISI:000353753200006, title = {Facile gamma radiolytic methodology for TiO2-rGO synthesis: effect on photo-catalytic H-2 evolution}, journal = {International Journal of Hydrogen Energy}, volume = {40}, number = {17}, year = {2015}, month = {MAY}, pages = {5815-5823}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

TiO2 (P25) decorated reduced graphene oxide (rGO) is synthesized by gamma-radiolytic technique using water-ethanol solvent medium. Visible light absorpdon was confirmed by UV-Visible spectroscopy. Photoluminescence (PL) study revealed a decline in electron-hole recombination rate signalled by a sharp fall in luminescence of TiO2. Under such scenario, electron transfer from TiO2 conduction band to the conjugated sheet becomes a preferred pathway in the presence of rGO, which is further confirmed by photocurrent measurement. TiO2 -rGO composite with 1 wt. \% rGO was found to be the best composition in terms of visible light absorption, while retaining TiO2 crystallinity. Transmission electron microscopy and Raman spectroscopic studies confirmed the coating of rGO sheet with TiO2 nanoparticles. TiO2 -rGO was found to show about 150 times higher photocatalytic H-2 generation under 250 W UV-Visible light irradiation than pristine TiO2. In addition to this, TiO2 -rGO composite shows hydrogen production yield of 35 mu mol/h.g under visible light (lambda = 400 nm) irradiation. Thus gamma-radiolysis can be considered to be a viable technique, which helps in synthesizing photocatalytically active nanocomposite with high H-2 evolution rate. In the light of these interesting aspects, a detail investigation is carried out to study the effect of rGO concentration and illumination time on photocatalytic yield. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

}, keywords = {gamma-radiolysis, H-2 production, Photocatalysis, Reduced graphene oxide, TiO2}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2015.02.102}, author = {Gupta, Bhavana and Melvin, Ambrose A. and Matthews, Tom and Dhara, S. and Dash, Sitaram and Tyagi, A. K.} } @article {46953, title = {Controlling and stabilization of Ru nanoparticles by tuning the nitrogen content of the support for enhanced H-2 production through aqueous-phase reforming of glycerol}, journal = {ACS Catalysis}, volume = {10}, year = {2020}, month = {FEB}, pages = {2489-2507}, type = {Article}, abstract = {

The stable activity of catalysts is an important issue in catalysis, particularly aqueous-phase reforming (APR) of renewable oxygenates, of biomass origin, to get H-2. Sintering of metal nanoparticles on supports affects catalyst stability. To alleviate this problem, a series of highly stable Ru-supported catalysts with controlled metal nanoparticle sizes have been prepared via the easy incipient wetness impregnation method. These catalysts were used for APR of glycerol to produce H-2. Nitrogen-doped mesoporous carbons (NMCs) were utlized as supports and found to have a strong influence on the catalytic performance of the catalysts. Incorporation of nitrogen in the carbon framework significantly enhanced the catalytic activity compared to Ru catalysts on nitrogen-free supports. Notably, the catalyst (5 wt \% Ru-NMC-3) with optimal N content (10.9 wt \%) demonstrated improved stability and H-2 selectivity, which are better than those of many state-of-the-art catalysts. Nitrogen in the carbon framework has a dual relationship with the activity of the catalyst: (i) it creates basic environment over the catalysts support and (ii) it acts as an anchoring site for metal nanoparticles. Anchoring of metal nanoparticles has helped to curb their sintering, thus leading to better stability of the catalysts under APR reaction conditions. Various characterization techniques were employed to understand the nature of active catalytic sites responsible for higher H-2 production while minimizing CO formation. In situ CO-FTIR studies showed that the higher catalytic activity of 5 wt \% Ru-NMC-3 catalyst was attributed to the enhanced WGS activity over this catalyst. Density functional theory calculations were performed to understand the stabilization of metal nanoparticles by different types of N present on the support and provide insights into the prefered sites of glycerol adsorption on the NMC support. Since S wt \% Ru-NMC-3 was the relatively best catalyst, it was selected for the preparation of bimetallic catalysts. Accordingly, addition of Pt to this system helped to increase the stability of the catalyst. This bimetallic catalyst may, therefore, find application for wide use in APR of biomass oxygenates.

}, keywords = {aqueous-phase reforming, Glycerol, H-2 production, Ru/NMC catalyst, synergistic effect}, issn = {2155-5435}, doi = {10.1021/acscatal.9b04063}, author = {Gogoi, Pranjal and Kanna, Narsimharao and Begum, Pakiza and Deka, Ramesh C. and Satyanarayana, C. V. V. and Raja, Thirumalaiswamy} } @article {49885, title = {Energy-saving H2 production through H2S electrolysis accompanying solid sulfur recovery using a Ni3S2/Ni3N heterostructure as the electrocatalyst}, journal = {ACS Applied Energy Materials}, volume = {8}, year = {2025}, month = {SEP }, pages = {13631-13644}, type = {Article}, abstract = {

The thermodynamically feasible electrochemical sulfion oxidation reaction (SOR) is advantageous for degrading the toxic H2S pollutant into the value-added chemical sulfur but often suffers from catalyst passivation due to blockage of electroactive sites by accumulation of solid sulfur. The strategic design of electrocatalysts with enhanced electrochemical activity and improved sulfur tolerance is thereby crucial to fully harness the benefits of the SOR. In this work, we developed nickel sulfide nanorods decorated with nickel nitride nanoparticles directly grown on conductive nickel foam as an efficient trifunctional electrocatalyst for the SOR, oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). Optimized Ni3S2/Ni3N showed lower electrode potentials of 0.25, 1.487, and 0.89 V to achieve a benchmark current density of 10 mA cm(-2) for the SOR, OER, and HER, respectively. The hybrid H2S electrolysis setup employing a Ni3S2/Ni3N electrocatalyst drastically reduced the cell potential by 1.24 V compared to that of conventional water electrolysis at a current density of 200 mA cm(-2). Having said that, heterostructure formation not only enhances the activity for the SOR but also helps to avoid sulfur poisoning, enabling the electrocatalyst to sustain for 100 long hours at a high current density of 100 mA cm(-2). Consequently, the approach with the developed electrocatalyst has the ability to reduce the energy consumption by 59.22\%, which can make rigorous, economically viable H-2 production driven by solar energy.

}, keywords = {energy-economic, H-2 production, H2S electrolysis, heterostructure, solidsulfur}, issn = {2574-0962}, doi = {10.1021/acsaem.5c01952}, author = {Sinha, Nibedita and Das, Chandni and Pal, Santanu and Roy, Poulomi} }