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Sn-Fe5(PO4)4(OH)3.2H2O/graphene: A new electrode for superior rate applications in Li/Na ion batteries
No full textA novel Sn-Fe5(PO4)4(OH)3.2H2O, otherwise known as (Sn-FeHP) is prepared by hydrothermal method and
subsequently, Sn-FeHP/G composite containing graphene is obtained by adopting a simple mechanothermal
approach. Not requiring the addition of surfactant or template, the currently adopted hydrothermal strategy
produces flower like morphology with a polyhedral rod assembly. When it is explored as Li-ion battery anode, a
steady state capacity of 1000 mA h g−1 is demonstrated by Sn-FeHP/G under the influence of 100 mA g−1
current density with an excellent Coulombic efficiency of 99% up to 100 cycles. The title anode demonstrates its
suitability for high capacity and high rate applications by exhibiting appreciable capacity values of 520, 450, and
350 mA h g−1
, under the influence of 2, 3 and 5 A g−1 respectively. Further, Sn-FeHP/G composite anode demonstrates the suitability for Na-ion batteries by exhibiting 195 and 160 mA h g−1 of capacity under the influence of 50 and 100 mA g−1 up to 1000 and 100 cycles respectively. The study recommends Sn-FeHP/G
composite for its exploitation as an alternative anode for high-performance lithium-ion and sodium-ion batterie
Recent progress on earth abundant electrocatalysts for oxygen evolution reaction (OER) in alkaline medium to achieve efficient water splitting – A review
No full textDeveloping earth-abundant-electrocatalysts for oxygen evolution reaction is one of the promising ways to achieve
efficient water-splitting for hydrogen production (a clean chemical fuel). This paper reviews the activity, stability and
durability for oxygen evolution reaction in alkaline medium of different types of recently reported electrocatalysts
such as Ni, Co, NiCo, Fe, Se, Mo, Cu, Mn, Zn, V, Ti/Ta, and metal free based earth-abundant-electrocatalysts. Further,
this paper reviews the strategies used to achieve the remarkably low overpotential (including η10: ≤100mV), high
long term stability (including ≥100 h) and high durability (including ≥5000 cycles) of earth-abundant-electrocatalysts
for oxygen evolution reaction in alkaline medium and those are better or well comparable with the state-ofthe-
art IrO2 electrocatalyst2. Finally, this paper summarizes the efficient strategies such as preparing porous or
nanostructured materials, preparing quantum sized materials, doping metals or heteroatoms, tuning the optimal
crystal structure, preparing bimetallic/multi-metallic materials, preparing materials with oxygen vacancies/defects,
preparing amorphous materials, preparing metal chalcogenides, preparing metal oxy hydroxides, and integrating
electrocatalysts with carbon to enhance the activity, stability, and durability for OER
Methanol electro-oxidation by nanostructured Pt/Cu bimetallic on poly 3,4 ethylenedioxythiophene (PEDOT)
No full textHerein, we report the preparation, characterisation and electrocatalysis of Pt/Cu bimetallic nanostructure
formed on Poly 3,4 ethylenedioxythiophene (PEDOT) modified glassy carbon electrode, Pt-Cu-PEDOT/GC.
A three-step procedure was adopted for the fabrication of the catalyst. Initially the glassy carbon electrode (GC) was modified by a uniform coating of PEDOT by potential cycling. Copper NPs were then
deposited on the PEDOT film by deposition from a 2 mM solution of CuSO4 in 0.1 M NaClO4 at a constant
potential of �0.477 V vs. SCE. Pt/Cu-PEDOT/GC catalyst was prepared by substitution of copper by
galvanic displacement with various concentrations of H2PtCl6. The electrode thus prepared displayed
very good electrocatalytic effect for methanol oxidation characterized by cyclic voltammetry. It was
found that the catalyst prepared with 2 mM H2PtCl6 exhibited the highest catalytic activity, with If/Ib
values of 1.80 and 1.38 for methanol concentrations of 1 M and 5 M, respectively. At a relatively low Pt
loading of 5.48 10�6
/cm2
, the Pt/Cu-PEDOT/GC should be a cost-effective alternative anode catalyst for
DMFC
Non-enzymatic electrochemical hydrogen peroxide detection using MoS2- Interconnected porous carbon heterostructure
No full textSensitive and non-enzymatic electrochemical hydrogen peroxide (H2O2) sensor was fabricated using molybdenum disulphide (MoS2)-Interconnected porous carbon (ICPC) heterostructure. The structural properties of
synthesized MoS2, ICPC and MoS2-ICPC materials were examined by various spectroscopy and microscopy
techniques. These results confirmed that the support matrix play a crucial role for the formation of different size
of MoS2. The structure of MoS2 altered to nanosized while growing on the support matrix. The electrochemical
H2O2 sensing characteristics of MoS2-ICPC composite material exhibited superior activity than individual MoS2
and ICPC materials. The results concluded that the interconnected porous carbon might stimulate the structural modification of MoS2 with enhance exposed active edge sites, which is responsible for higher electrochemical activity. The composite material exhibited a detection limit of 11.8 μM H2O2 with higher sensitivity, selectivity, and long-term stability. These results open a novel way to build MoS2-ICPC material for active electrochemical sensor application
Hierarchical approach of mitigating carbon influence in nano-porous electro-catalyst with unique surface islands for efficient methanol resistive oxygen reduction
No full textFor the first time, we report a facile one pot aqueous method for support-free Pd85Pt15 nano-porous
structures (NPoS) synthesis from PdMn nano-alloys at ambient conditions. A hierarchical approach
was successfully employed through a simple “self-settlement” process with descending amounts of
carbon to carbon-free electro-catalysts to improve catalyst utilization and avoid carbon degradation
during fuel cell operating conditions. Pd85Pt15 NPoS exhibits enhanced methanol resistive oxygen
reduction reaction (ORR) activity owing to the presence of highly active and unique surface PdPt islands
compared to HiSPEC Pt/C catalysts. Accelerated durability tests of the support-free PdPt NPoS show
enhanced durability in harsh acidic environment (1.0 N H2SO4) compared to HiSPEC Pt/C and DOE 2017
e2020 durability target. Preliminary direct methanol fuel cell studies using hierarchically derived
Pd85Pt15 NPoS variants were performed at ultra-low Pt content. The effects of carbon content and catalyst
layer thickness on fuel cell activities are well discusse
Metal organic framework laden poly(ethylene oxide) based composite electrolytes for all-solid-state Li-S and Li-metal polymer batteries
No full textIn this work, the possibility of employing aluminium terephthalic acid metal organic framework (Al-TPAMOF)-
laden composite polymer membranes as electrolyte for all-solid-state lithium-sulfur (Li-S) and
lithium-metal (Li-metal) polymer batteries is explored. The prepared composite polymer electrolytes
(CPEs) based on a poly(ethylene oxide) (PEO) network with lithium bis(trifluoromethane)sulfonimide
(LiTFSI) and Al-TPA-MOF are mechanically robust and thermally stable up to 270 �C, and provide
appreciable ionic conductivity in the order of 0.1mS cm�1 at 60 �C. The enhanced compatibility of CPEs
with the lithium metal anode is attributed to the scavenging effect of Al-TPA-MOF. Laboratory scale allsolid-
state Li-S and Li-metal polymer cells are assembled, which deliver specific capacities exceeding 800
and 130mAh g�1, respectively, and a stable performance upon prolonged cycling even at 60 �C, which is
superior to earlier reports on similar systems
Simple room temperature synthesis of porous nickel phosphate foams for electrocatalytic ethanol oxidation
No full textThe simple and eco-friendly fabrication of non-noble metal catalyst is of great importance for sustainable energy
production from alcohol. Herein, we report the new synthetic route for the preparation of nickel phosphate
nanostructure through simple co-precipitation method. We studied the effect of annealing temperature ranging
from 500 °C to 1100 °C on the electrocatalyst for ethanol electro-oxidation. In addition, we demonstrate that the
resulting nickel phosphate materials can serve as efficient transition metal electrocatalyst for the ethanol oxidation under alkaline condition. In particular, the nickel phosphate annealed at 900 °C (NP-900) affords higher
current density of 1.2 mA cm−2 at the low potential of 0.7 mV, demonstrating great catalytic stability as well as
good cyclability for 1000 cycles giving about 92% faradaic yield towards the ethanol
Electrochemical synthesis of Au-Ni(OH)2-nanocomposite on glassy carbon electrode as highly active bifunctional electrocatalyst for oxygen evolution and oxygen reduction reactions
No full textIn this work, we demonstrated an electrochemical method to prepare Au-Ni(OH)2-nanocomposite on a glassy
carbon substrate (Au-Ni(OH)2-NC/GCE). This modified nanocomposite showed high electrocatalytic activity
towards oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) compared to similarly prepared
Au free Ni(OH)2-NC/GCE. The above nanocomposite was prepared through two step processes; first gold‑nickel
hexacyanoferrate nanocomposite film on GCE (Au-NiHCF-NC/GCE) was synthesized by single step electrochemical cycling approach. Later, the Au-NiHCF-NC/GCE was treated electrochemically in alkaline solution to
produce Au-Ni(OH)2-NC/GCE. The as-formed Au-Ni(OH)2-NC/GCE was used as a bifunctional electrode to study
the OER and ORR in alkaline solution. The resulting nanocomposite exhibits high electrocatalytic activity and
fast electron transfer kinetics due to the synergic effect of the formation of more active β-Ni(OH)2 phase and Au nanoparticles (AuNPs) during the electrochemical cycling process
3,5-Diamino-1,2,4-triazole@electrochemically reduced graphene oxide film modified electrode for the electrochemical determination of 4-nitrophenol Deivasigamani Ranjith
No full textIn this study, an eco-friendly benign method for the modification of electrochemically reduced graphene
oxide (ERGO) on glassy carbon (GC) surface and electrochemical polymerized 3,5-diamino-1,2,4-triazole
(DAT)
film composite (pDAT@ERGO/GC) electrode was developed. The surface morphologies of the
pDAT@ERGO/GC modified electrode were analyzed by
field emission scanning electron microscopy
(FESEM). FESEM images indicated that the ERGO supported pDAT has an almost homogeneous
morphology structure with a size of 70 to 80 nm. It is due to the water oxidation reaction occurred while
pDAT@ERGO/GC fabrication peak at +1.4 V leads to O2 evolution and oxygen functional group
functionalization on ERGO, which confirmed by X-ray photoelectron spectroscopy (XPS). In contrast,
the bare GC modified with pDAT showed randomly arranged irregular bulky morphology structure
compared to those of pDAT@ERGO/GC. Electrochemical reduction of graphene oxide was confirmed by
Raman spectroscopy, XPS, and electrochemical impedance spectroscopy (EIS). The pDAT@ERGO/GC
modified electrode was used for the electrochemical determination of 4-nitrophenol (4-NP). The 4-NP
oxidation peak was observed at +0.25 V, and the differential pulse voltammetry demonstrated wide
concentration range (5–1500 mM), high sensitivity (0.7113 mA mM�1), and low limit of detection (37 nM).
Moreover, the pDAT@ERGO/GC electrode was applied to real water sample analysis by standard addition
method, where in good recoveries (97.8% to 102.4%) were obtained
Synthesis of flower-like molybdenum sulfide/graphene hybrid as an efficient oxygen reduction electrocatalyst for anion exchange membrane fuel cells
No full textNanostructured transition metal chalcogenides (TMCs) have significant interest towards electrochemical
devices such as fuel cells, metal-ion batteries, due to their unique physical and electrochemical properties.
Herein, we report a facile hydrothermal synthesis of flower-like nanostructured molybdenum
sulphide and its incorporation on to graphene as a potential oxygen reduction reaction catalyst in
alkaline medium. The phase purity and morphological evolution of MoS2 is systematically studied
through X-ray diffraction and scanning electron microscopic techniques. The electronic states of metal
and non-metallic species are deeply studied by X-ray photoelectron spectroscopy. The effect of annealing
temperatures and TMC concentrations are also investigated by electrochemical techniques such as cyclic
and linear sweep voltammograms. The optimised electrocatalyst (MoS2/G-500) delivers significant ORR
activity with onset and half-wave potentials of 0.91 and 0.80 V (vs. RHE), respectively. Superior durability
compared to state-of-art Pt/C catalyst is ascertained by repeating potential cycles for about 5000 times
and also by chronoamperometric technique. Finally, the hybrid catalyst is evaluated in AEMFC as cathode
catalyst which delivers peak power density of about 29 mW cm�2 under ambient temperature and
pressure. The present findings emphasis that MoS2/G catalyst is promising as cost-effective and alternative
to noble metal-based catalysts for fuel cell applications