Hollow nitrogen-doped carbon spheres as efficient and durable electrocatalysts for oxygen reduction

Sanetuntikul, Jakkid,Hang, Tao,Shanmugam, Sangaraju The Royal Society of Chemistry 2014 Chemical communications Vol.50 No.67

<P>Hollow nitrogen-doped carbon spheres (HNCSs) were prepared by a facile method as non-precious catalysts for the oxygen reduction reaction (ORR). The HNCS catalysts exhibited ORR activity comparable with a commercial Pt/C catalyst and superior stability in alkaline electrolyte medium.</P> <P>Graphic Abstract</P><P>Hollow nitrogen-doped carbon spheres showed oxygen reduction activity comparable with a commercial Pt/C catalyst and excellent stability in alkaline electrolyte medium. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4cc03437f'> </P>

Cobalt and nitrogen co-doped hierarchically porous carbon nanostructure: a bifunctional electrocatalyst for oxygen reduction and evolution reactions

Sanetuntikul, Jakkid,Hyun, Suyeon,Ganesan, Pandian,Shanmugam, Sangaraju The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.47

<P>Designing efficient and cost-effective electrocatalysts is a great challenge for oxygen reduction and evolution reactions (ORR/OER). Herein, we describe the fabrication of Co and N co-doped porous carbon-based catalysts (CoNPCs) using a single step method. The CoNPCs show good electrocatalytic activity and long-term durability due to the presence of plentiful Co and N active sites and highly porous nanostructures. Further demonstration in alkaline fuel cell and Zn-air battery devices shows remarkable performance as an efficient non-precious metal electrode.</P>

High pressure pyrolyzed non-precious metal oxygen reduction catalysts for alkaline polymer electrolyte membrane fuel cells

Sanetuntikul, Jakkid,Shanmugam, Sangaraju The Royal Society of Chemistry 2015 Nanoscale Vol.7 No.17

<▼1><P>Fe–N–C exhibited better activity and stability compared to Pt/C in an alkaline electrolyte. Fe–N–C showed a comparable fuel cell performance to Pt/C.</P></▼1><▼2><P>Non-precious metal catalysts, such as metal-coordinated to nitrogen doped-carbon, have shown reasonable oxygen reduction reaction (ORR) performances in alkaline fuel cells. In this report, we present the development of a highly active, stable and low-cost non-precious metal ORR catalyst by direct synthesis under autogenic-pressure conditions. Transmission electron microscopy studies show highly porous Fe–N–C and Co–N–C structures, which were further confirmed by Brunauer–Emmett–Teller surface area measurements. The surface areas of the Fe–N–C and Co–N–C catalysts were found to be 377.5 and 369.3 m<SUP>2</SUP> g<SUP>−1</SUP>, respectively. XPS results show the possible existence of N–C and M–Nx structures, which are generally proposed to be the active sites in non-precious metal catalysts. The Fe–N–C electrocatalyst exhibits an ORR half-wave potential 20 mV higher than the reference Pt/C catalyst. The cycling durability test for Fe–N–C over 5000 cycles shows that the half-wave potential lost only 4 mV, whereas the half-wave potential of the Pt/C catalyst lost about 50 mV. The Fe–N–C catalyst exhibited an improved activity and stability compared to the reference Pt/C catalyst and it possesses a direct 4-electron transfer pathway for the ORR process. Further, the Fe–N–C catalyst produces extremely low HO2<SUP>−</SUP> content, as confirmed by the rotating ring-disk electrode measurements. In the alkaline fuel single cell tests, maximum power densities of 75 and 80 mW cm<SUP>−2</SUP> were observed for the Fe–N–C and Pt/C cathodes, respectively. Durability studies (100 h) showed that decay of the fuel cell current was more prominent for the Pt/C cathode catalyst compared to the Fe–N–C cathode catalyst. Therefore, the Fe–N–C catalyst appears to be a promising new class of non-precious metal catalysts prepared by an autogenic synthetic method.</P></▼2>

Investigation of hollow nitrogen-doped carbon spheres as non-precious Fe–N₄ based oxygen reduction catalysts

Sanetuntikul, Jakkid,Chuaicham, Chitiphon,Choi, Young-Woo,Shanmugam, Sangaraju The Royal Society of Chemistry 2015 Journal of materials chemistry. A, Materials for e Vol.3 No.30

<▼1><P>The effect of nitrogen type and content along with metal doping in hollow carbon spheres on oxygen reduction activity is described.</P></▼1><▼2><P>The development of inexpensive non-precious oxygen reduction catalysts has become one of the most important efforts in polymer electrolyte membrane fuel cells. In this report, we synthesized a non-precious electrocatalyst from a single precursor, iron(iii) diethylene triaminepentaacetate, using a heat-treatment effect to prepare an active catalyst. A series of catalysts were prepared at different temperatures leading to different degrees of graphitization, heteroatom content and activity. In 0.1 M KOH electrolyte solution, the oxygen reduction reaction (ORR) onset potential of the HNCS71 catalyst was as high as 0.97 V, and half-wave potentials were only 20 mV lower than those for Pt/C. X-ray absorption measurements of the Fe K-edge showed the structure of Fe–N4 centers, formed in HNCS71, which were responsible for the ORR activity. An alkaline exchange membrane fuel cell fabricated with HNCS71 as the cathode was tested in a H2–O2 single cell and showed a maximum power density of ∼68 mW cm<SUP>−2</SUP>. The 100 hour fuel cell durability test of the HNCS71 cathode showed a decay in the current density of about 14% at 0.4 V. Therefore, the HNCS catalyst appears to be a promising new class of non-precious catalysts for fuel cell applications.</P></▼2>

Polyoxometalate decorated graphene oxide/sulfonated poly(arylene ether ketone) block copolymer composite membrane for proton exchange membrane fuel cell operating under low relative humidity

Oh, Kwangjin,Son, Byungrak,Sanetuntikul, Jakkid,Shanmugam, Sangaraju Elsevier 2017 Journal of membrane science Vol.541 No.-

<P><B>Abstract</B></P> <P>A phosphotungstic acid (PW) decorated graphene oxide (GO) is explored as a filler for sulfonated poly(arylene ether ketone) (SPAEK) block copolymer. The SPAEK/PW-mGO composite membrane shows higher proton conductivity than a pristine SPAEK membrane. At 80°C under 25% relative humidity (RH) condition, the fuel cell configured with the SPAEK/PW-mGO composite membrane shows improved fuel cell performance. A maximum power density of 772mWcm<SUP>−2</SUP> is observed for the SPAEK/PW-mGO composite membrane, whereas the pristine SPAEK membrane exhibits a maximum power density of 10mWcm<SUP>−2</SUP> operated under 25% RH at 80°C. Compared with the NRE-212 membrane, the SPAEK/PW-mGO composite membrane exhibits 4.8-times higher maximum power density. Furthermore, the maximum current density of the SPAEK/PW-mGO composite membrane (2271mAcm<SUP>−2</SUP>) is much higher than pristine SPAEK (39mAcm<SUP>−2</SUP>) and NRE-212 (734mAcm<SUP>−2</SUP>) membranes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> SPAEK/PW-mGO composite membrane is successfully developed. </LI> <LI> Improvement of water uptake, IEC value, ionic cluster size, and proton conductivity. </LI> <LI> Outstanding fuel cell performance at 80°C under low relative humidity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Sonochemical Formation of Ga-Pt Intermetallic Nanoparticles Embedded in Graphene and its Potential Use as an Electrocatalyst

Kumar, V.B.,Sanetuntikul, J.,Ganesan, P.,Porat, Z.,Shanmugam, S.,Gedanken, A. Pergamon Press 2016 Electrochimica Acta Vol. No.

The formation of Ga-Pt particles and their simultaneous embedment in graphene layers was performed by sonication of molten gallium in an aqueous solution of H<SUB>2</SUB>PtCl<SUB>6</SUB> in the presence of graphene. X-ray analysis of the dry particles revealed that their composition was GaPt<SUB>3</SUB> and GaPt<SUB>2.</SUB> The synthesized Ga-Pt/G was examined as an electrode material for methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR). This novel electrode showed better activity for MOR and ORR than a commercial Pt/C catalyst.

Development of a simple bioelectrode for the electrochemical detection of hydrogen peroxide using <i>Pichia pastoris</i> catalase immobilized on gold nanoparticle nanotubes and polythiophene hybrid

Nandini, Seetharamaiah,Nalini, Seetharamaiah,Sanetuntikul, Jakkid,Shanmugam, Sangaraju,Niranjana, Pathappa,Melo, Jose Savio,Suresh, Gurukar Shivappa The Royal Society of Chemistry 2014 The Analyst Vol.139 No.22

<P>In this paper, a simple and innovative electrochemical hydrogen peroxide biosensor has been proposed using catalase (CAT<SUB>pp</SUB>) derived from <I>Pichia pastoris</I> as bioelectrocatalyst. The model biocomponent was immobilized on gold nanoparticle nanotubes (AuNPNTs) and polythiophene composite using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide and <I>N</I>-hydroxysuccinimide (EDC–NHS) coupling reagent. In this present work, we have successfully synthesized gold nanoparticles (AuNPs) by ultrasonic irradiation. The tubular gold nanostructures containing coalesced AuNPs were obtained by sacrificial template synthesis. The assembly of AuNPNTs onto the graphite (Gr) electrode was achieved <I>via</I> S–Au chemisorption. The latter was pre-coated with electropolymerized thiophene (PTh) to enable S groups to bind AuNPNTs. The combination of AuNPNTs–PTh, <I>i.e.</I>, an inorganic–organic hybrid, provides a stable enzyme immobilization platform. The physical morphology of the fabricated biosensor Gr/PTh/AuNPNTs/EDC–NHS/CAT<SUB>pp</SUB> was investigated using scanning electron microscopy and energy-dispersive microscopy. The analytical performance of the bioelectrode was examined using cyclic voltammetry, differential pulse voltammetry and chronoamperometry. Operational parameters such as working potential, pH, and thermal stability of the modified electrode were examined. The beneficial analytical characteristics of the proposed electrode were demonstrated. Our results indicate that the Gr/PTh/AuNPNTs/EDC–NHS/CAT<SUB>pp</SUB> bioelectrode exhibits a wide linear range from 0.05 mM to 18.5 mM of H<SUB>2</SUB>O<SUB>2</SUB>, fast response time of 7 s, excellent sensitivity of 26.2 mA mM<SUP>−1</SUP> cm<SUP>−2</SUP>, good detection limit of 0.12 μM and good Michaelis–Menten constant of 1.4 mM. In addition, the bioelectrode displayed good repeatability, high stability and acceptable reproducibility, which can be attributed to the AuNPNTs–PTh composite that provides a biocompatible micro-environment.</P> <P>Graphic Abstract</P><P>We have developed an electrochemical H<SUB>2</SUB>O<SUB>2</SUB> biosensor using AuNPNTs PTh and CAT<SUB>pp</SUB>. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c4an01262c'> </P>

The graphitic carbon-encapsulated magnetic nanoparticles synthesized by one-pot synthesis induced necrotic cell

Jung-Hee KIM,Jakkid SANETUNTIKUL,Sangaraju SHANMUGAM,Eunjoo KIM 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8