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Huang YC, Wang YZ, Hsieh TH, Ho KS. Co(II)-Chelated Polyimines as Oxygen Reduction Reaction Catalysts in Anion Exchange Membrane Fuel Cells. MEMBRANES 2023; 13:769. [PMID: 37755192 PMCID: PMC10536383 DOI: 10.3390/membranes13090769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/28/2023] [Accepted: 08/23/2023] [Indexed: 09/28/2023]
Abstract
In this paper, a cobalt (Co)-chelated polynaphthalene imine (Co-PNIM) was calcined to become an oxygen reduction reaction (ORR) electrocatalyst (Co-N-C) as the cathode catalyst (CC) of an anion exchange membrane fuel cell (AEMFC). The X-ray diffraction pattern of CoNC-1000A900 illustrated that the carbon matrix develops clear C(002) and Co(111) planes after calcination, which was confirmed using high-resolution TEM pictures. Co-N-Cs also demonstrated a significant ORR peak at 0.8 V in a C-V (current vs. voltage) curve and produced an extremely limited reduction current density (5.46 mA cm-2) comparable to commercial Pt/C catalysts (5.26 mA cm-2). The measured halfway potential of Co-N-C (0.82 V) was even higher than that of Pt/C (0.81 V). The maximum power density (Pmax) of the AEM single cell upon applying Co-N-C as the CC was 243 mW cm-2, only slightly lower than that of Pt/C (280 mW cm-2). The Tafel slope of CoNC-1000A900 (33.3 mV dec-1) was lower than that of Pt/C (43.3 mV dec-1). The limited reduction current density only decayed by 7.9% for CoNC-1000A900, compared to 22.7% for Pt/C, after 10,000 redox cycles.
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Affiliation(s)
- Yu-Chang Huang
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan
| | - Yen-Zen Wang
- Department of Chemical and Materials Engineering, National Yu-Lin University of Science & Technology, 123, Sec. 3, University Road, Dou-Liu City, Yun-Lin 64301, Taiwan
| | - Tar-Hwa Hsieh
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan
| | - Ko-Shan Ho
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan
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Tang P, Huang PY, Swallow JEN, Wang C, Gianolio D, Guo H, Warner JH, Weatherup RS, Pasta M. Structure-Property Relationship of Defect-Trapped Pt Single-Site Electrocatalysts for the Hydrogen Evolution Reaction. ACS Catal 2023; 13:9558-9566. [PMID: 37497376 PMCID: PMC10367054 DOI: 10.1021/acscatal.3c01513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/15/2023] [Indexed: 07/28/2023]
Abstract
Single-site catalysts (SSCs) have attracted significant research interest due to their high metal atom utilization. Platinum single sites trapped in the defects of carbon substrates (trapped Pt-SSCs) have been proposed as efficient and stable electrocatalysts for the hydrogen evolution reaction (HER). However, the correlation between Pt bonding environment, its evolution during operation, and catalytic activity is still unclear. Here, a trapped Pt-SSC is synthesized by pyrolysis of H2PtCl6 chemisorbed on a polyaniline substrate. In situ heated scanning transmission electron microscopy and temperature-dependent X-ray photoelectron spectroscopy clarify the thermally induced structural evolution of Pt during pyrolysis. The results show that the nitrogen in polyaniline coordinates with Pt ions and atomically disperses them before pyrolysis and traps Pt sites at pyridinic N defects generated during the substrate graphitization. Operando X-ray absorption spectroscopy confirms that the trapped Pt-SSC is stable at the HER working potentials but with inferior electrocatalytic activity compared with metallic Pt nanoparticles. First principle calculations suggest that the inferior activity of trapped Pt-SSCs is due to their unfavorable hydrogen chemisorption energy relative to metallic Pt(111) surfaces. These results further the understanding of the structure-property relationship in trapped Pt-SSCs and motivate a detailed techno-economic analysis to evaluate their commercial applicability.
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Affiliation(s)
- Peng Tang
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - Po-Yuan Huang
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - Jack E. N. Swallow
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - Chenbo Wang
- Oxford
Suzhou Centre for Advanced Research, 388 Ruoshui Road, Suzhou 215123, Jiangsu Province, P. R. China
| | - Diego Gianolio
- Diamond
Light Source Ltd., Harwell Science and Innovation
Campus, Chilton, Didcot, OX11 0DE, U.K.
| | - Hua Guo
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - Jamie H. Warner
- Materials
Graduate Program, Texas Materials Institute, The University of Texas at Austin, 204 East Dean Keeton Street, Austin, Texas, 78712, United States
- Walker
Department of Mechanical Engineering, The
University of Texas at Austin, 204 East Dean Keeton Street, Austin, Texas, 78712, United States
| | - Robert S. Weatherup
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - Mauro Pasta
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
- Oxford
Suzhou Centre for Advanced Research, 388 Ruoshui Road, Suzhou 215123, Jiangsu Province, P. R. China
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Izadyar A, Van MN, Miranda M, Weatherford S, Hood EE, Seok I. Development of a highly sensitive glucose nanocomposite biosensor based on recombinant enzyme from corn. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2022; 102:6530-6538. [PMID: 35587543 DOI: 10.1002/jsfa.12019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/11/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Enzymes are biocatalysts that play a vital role in the production of biomolecules. Plants can be a valuable and cost-effective source for producing well-structured recombinant enzymes. Glucose is one of the most important biological molecules, providing energy to most living systems. An electrochemical method for immobilization of enzyme is promising because it is economic, generates less component waste, improves the signal-to-noise ratio, leads to a lower limit of detection, and stabilizes and protects the enzyme structure. RESULTS A glucose biosensor was constructed using polyaniline (PANI) and a recombinant enzyme from corn, plant-produced manganese peroxidase (PPMP), with polymerization of aniline as a monomer in the presence of gold nanoparticles (AuNPs)-glucose oxidase (GOx), and bovine serum albumin. Using linear sweep voltammetry and cyclic voltammetry techniques, PANI-AuNPs-GOx-PPMP/Au electrode exhibited a superior sensing property with a wider linear range of 0.005-16.0 mm, and a lower detection limit of 0.001 mm compared to PANI-GOx-PPMP/Au electrode and PANI-GOx-PPMP/AuNPs/Au electrode. The biosensor selectivity was assessed by determining glucose concentrations in the presence of ascorbic acid, dopamine, aspartame, and caffeine. CONCLUSION We conclude that a plant-produced Mn peroxidase enzyme combined with conductive polymers and AuNPs results in a promising nanocomposite biosensor for detecting glucose. The use of such devices for quality control in the food industry can have a significant economic impact. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Anahita Izadyar
- Department of Chemistry and Physics, Arkansas State University, Jonesboro, AR, USA
| | - My Ni Van
- Department of Chemistry and Physics, Arkansas State University, Jonesboro, AR, USA
| | - Marcela Miranda
- Department of Chemistry and Physics, Arkansas State University, Jonesboro, AR, USA
| | - Scout Weatherford
- Department of Chemistry and Physics, Arkansas State University, Jonesboro, AR, USA
| | - Elizabeth E Hood
- Arkansas Biosciences Institute and College of Agriculture, Arkansas State University, Jonesboro, AR, USA
| | - Ilwoo Seok
- College of Engineering and Computer Science, Arkansas State University, Jonesboro, AR, USA
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Ozkan SZ, Kostev AI, Chernavskii PA, Karpacheva GP. Novel Hybrid Nanomaterials Based on Poly- N-Phenylanthranilic Acid and Magnetic Nanoparticles with Enhanced Saturation Magnetization. Polymers (Basel) 2022; 14:polym14142935. [PMID: 35890710 PMCID: PMC9320828 DOI: 10.3390/polym14142935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/11/2022] [Accepted: 07/16/2022] [Indexed: 11/16/2022] Open
Abstract
A one-step preparation method for cobalt- and iron-containing nanomaterials based on poly-N-phenylanthranilic acid (P-N-PAA) and magnetic nanoparticles (MNP) was developed for the first time. To synthesize the MNP/P-N-PAA nanocomposites, the precursor is obtained by dissolving a Co (II) salt in a magnetic fluid based on Fe3O4/P-N-PAA with a core-shell structure. During IR heating of the precursor in an inert atmosphere at T = 700−800 °C, cobalt interacts with Fe3O4 reduction products, which results in the formation of a mixture of spherical Co-Fe, γ-Fe, β-Co and Fe3C nanoparticles of various sizes in the ranges of 20 < d < 50 nm and 120 < d < 400 nm. The phase composition of the MNP/P-N-PAA nanocomposites depends significantly on the cobalt concentration. The reduction of metals occurs due to the hydrogen released during the dehydrogenation of phenylenamine units of the polymer chain. The introduction of 10−30 wt% cobalt in the composition of nanocomposites leads to a significant increase in the saturation magnetization of MNP/P-N-PAA (MS = 81.58−149.67 emu/g) compared to neat Fe3O4/P-N-PAA (MS = 18.41−27.58 emu/g). The squareness constant of the hysteresis loop is κS = MR/MS = 0.040−0.209. The electrical conductivity of the MNP/P-N-PAA nanomaterials does not depend much on frequency and reaches 1.2 × 10−1 S/cm. In the argon flow at 1000 °C, the residue is 77−88%.
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Affiliation(s)
- Sveta Zhiraslanovna Ozkan
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29 Leninsky Prospect, 119991 Moscow, Russia; (A.I.K.); (P.A.C.); (G.P.K.)
- Correspondence:
| | - Aleksandr Ivanovich Kostev
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29 Leninsky Prospect, 119991 Moscow, Russia; (A.I.K.); (P.A.C.); (G.P.K.)
| | - Petr Aleksandrovich Chernavskii
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29 Leninsky Prospect, 119991 Moscow, Russia; (A.I.K.); (P.A.C.); (G.P.K.)
- Department of Chemistry, Lomonosov Moscow State University, 1–3 Leninskie Gory, 119991 Moscow, Russia
| | - Galina Petrovna Karpacheva
- A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29 Leninsky Prospect, 119991 Moscow, Russia; (A.I.K.); (P.A.C.); (G.P.K.)
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Hsieh TH, Wang YZ, Ho KS. Cobalt-Based Cathode Catalysts for Oxygen-Reduction Reaction in an Anion Exchange Membrane Fuel Cell. MEMBRANES 2022; 12:membranes12070699. [PMID: 35877902 PMCID: PMC9319767 DOI: 10.3390/membranes12070699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/02/2022] [Accepted: 07/06/2022] [Indexed: 11/30/2022]
Abstract
A novel cobalt-chelating polyimine (Co-PIM) containing an additional amine group is prepared from the condensation polymerization of diethylene triamine (DETA) and terephthalalehyde (PTAl) by the Schiff reaction. A Co, N-co-doped carbon material (Co-N-C), obtained from two-stage calcination in different gas atmospheres is used as the cathode catalyst of an anion exchange membrane fuel cell (AEMFC). The Co-N-C catalyst demonstrates a CoNx-type single-atom structure seen under high-resolution transmission electron microscopy (HRTEM). The Co-N-C catalysts are characterized by FTIR, XRD, and Raman spectroscopy as well. Their morphologies are also illustrated by SEM and TEM micrographs, respectively. Surface area and pore size distribution are found by BET analysis. Co-N-C catalysts exhibit a remarkable oxygen reduction reaction (ORR) at 0.8 V in the KOH(aq). From the LSV (linear-sweeping voltammetry) curves, the onset potential relative to RHE is 1.19–1.37 V, the half wave potential is 0.73–0.78 V, the Tafel slopes are 76.9–93.6 mV dec−1, and the average number of exchange electrons is 3.81. The limiting reduction current of CoNC-1000A-900 is almost the same as that of commercial 20 wt% Pt-deposited carbon particles (Pt/C), and the max power density (Pmax) of the single cell using CoNC-1000A-900 as the cathode catalyst reaches 361 mW cm−2, which is higher than Pt/C (284 mW cm−2).
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Affiliation(s)
- Tar-Hwa Hsieh
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan;
| | - Yen-Zen Wang
- Department of Chemical and Materials Engineering, National Yu-Lin University of Science & Technology, 123, Section 3, University Road, Dou-Liu City 64301, Taiwan
- Correspondence: (Y.-Z.W.); (K.-S.H.)
| | - Ko-Shan Ho
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan;
- Correspondence: (Y.-Z.W.); (K.-S.H.)
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Hsieh TH, Chen SN, Wang YZ, Ho KS, Chuang JK, Ho LC. Cobalt-Doped Carbon Nitride Frameworks Obtained from Calcined Aromatic Polyimines as Cathode Catalyst of Anion Exchange Membrane Fuel Cells. MEMBRANES 2022; 12:membranes12010074. [PMID: 35054600 PMCID: PMC8779780 DOI: 10.3390/membranes12010074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/29/2021] [Accepted: 01/04/2022] [Indexed: 02/01/2023]
Abstract
Cobalt-doped carbon nitride frameworks (CoNC) were prepared from the calcination of Co-chelated aromatic polyimines (APIM) synthesized from stepwise polymerization of p-phenylene diamine (PDA) and o-phthalaldehyde (OPAl) via Schiff base reactions in the presence of cobalt (II) chloride. The Co-chelated APIM (Co-APIM) precursor converted to CoNC after calcination in two-step heating with the second step performed at 100 °C lower than the first one. The CoNCs demonstrated that its Co, N-co-doped carbonaceous framework contained both graphene and carbon nanotube, as characterized by X-ray diffraction pattern, Raman spectra, and TEM micropictures. CoNCs also revealed a significant ORR peak in the current–voltage polarization cycle and a higher O2 reduction current than that of commercial Pt/C in a linear scanning voltage test in O2-saturated KOH(aq). The calculated e-transferred number even reaches 3.94 in KOH(aq) for the CoNC1000A900 cathode catalyst, which has the highest BET surface area of 393.94 m2 g−1. Single cells of anion exchange membrane fuel cells (AEMFCs) are fabricated using different CoNCs as the cathode catalysts, and CoNC1000A900 demonstrates a peak power density of 374.3 compared to the 334.7 mW cm−2 obtained from the single cell using Pt/C as the cathode catalyst.
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Affiliation(s)
- Tar-Hwa Hsieh
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan; (T.-H.H.); (S.-N.C.); (J.-K.C.)
| | - Sin-Nan Chen
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan; (T.-H.H.); (S.-N.C.); (J.-K.C.)
| | - Yen-Zen Wang
- Department of Chemical and Materials Engineering, National Yu-Lin University of Science & Technology, 123, Sec. 3, University Rd., Dou-Liu City 64301, Taiwan
- Correspondence: (Y.-Z.W.); (K.-S.H.)
| | - Ko-Shan Ho
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan; (T.-H.H.); (S.-N.C.); (J.-K.C.)
- Correspondence: (Y.-Z.W.); (K.-S.H.)
| | - Jung-Kuan Chuang
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan; (T.-H.H.); (S.-N.C.); (J.-K.C.)
| | - Lin-Chia Ho
- Tri-Service General Hospital, 325 Sec. 2 Chenggong Rd., Neihu District, Taipei City 11490, Taiwan;
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Hsieh TH, Ho LC, Wang YZ, Ho KS, Tsai CH, Hung LF. New Inverse Emulsion-Polymerized Iron/Polyaniline Composites for Permanent, Highly Magnetic Iron Compounds via Calcination. Polymers (Basel) 2021; 13:polym13193240. [PMID: 34641057 PMCID: PMC8512439 DOI: 10.3390/polym13193240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/14/2021] [Accepted: 09/22/2021] [Indexed: 01/28/2023] Open
Abstract
The hydrophilic initiator potassium persulfate (KPS) was converted into a hydrophobic molecule by complexing with cetyltrimethylammonium bromide (CTAB) at both ends of the molecule (CTAPSu). Inverse emulsion polymerization thus proceeded inside micelles dispersed in the affluent toluene with CTAPSu as the initiator. Polyaniline (PANI) formed inside the micelles and entangled with Fe3O4 nanoparticles already esterified with oleic acid (OA). Iron composites consisted of OA-esterified Fe3O4 nanoparticles covered with PANI after de-emulsification. After calcination at 950 °C in an argon atmosphere, the resultant iron compound was a mixture of α-Fe (ferrite) and Fe3C (cementite), as determined by X-ray diffraction. Eventually, the calcined iron compounds (mixtures) demonstrated superparamagnetic properties with a high saturation magnetization (Ms) of 197 emu/g, which decayed to 160 emu/g after exposure to the atmosphere for four months.
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Affiliation(s)
- Tar-Hwa Hsieh
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science & Technology, 415 Chien-Kuo Rd., Kaohsiung 80782, Taiwan; (T.-H.H.); (C.-H.T.); (L.-F.H.)
| | - Lin-Chia Ho
- Tri-Service General Hospital, 325 Sec. 2 Chenggong Rd., Neihu District, Taipei City 11490, Taiwan;
| | - Yen-Zen Wang
- Department of Chemical and Materials Engineering, National Yu-Lin University of Science & Technology, 123, Sec. 3, University Rd., Dou-Liu City, Yun-Lin 64301, Taiwan
- Correspondence: (Y.-Z.W.); (K.-S.H.)
| | - Ko-Shan Ho
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science & Technology, 415 Chien-Kuo Rd., Kaohsiung 80782, Taiwan; (T.-H.H.); (C.-H.T.); (L.-F.H.)
- Correspondence: (Y.-Z.W.); (K.-S.H.)
| | - Cheng-Hsien Tsai
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science & Technology, 415 Chien-Kuo Rd., Kaohsiung 80782, Taiwan; (T.-H.H.); (C.-H.T.); (L.-F.H.)
| | - Li-Fan Hung
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science & Technology, 415 Chien-Kuo Rd., Kaohsiung 80782, Taiwan; (T.-H.H.); (C.-H.T.); (L.-F.H.)
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Superparamagnetic, High Magnetic α-Fe & α″-Fe 16N 2 Mixture Prepared from Inverse Suspension-Polymerized Fe 3O 4@polyaniline Composite. Polymers (Basel) 2021; 13:polym13142380. [PMID: 34301136 PMCID: PMC8309602 DOI: 10.3390/polym13142380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/08/2021] [Accepted: 07/15/2021] [Indexed: 01/31/2023] Open
Abstract
Oleic acid (OA)-modified Fe3O4 nanoparticles were successfully covered with polyanilines (PANIs) via inverse suspension polymerization in accordance with SEM and TEM micrographs. The obtained nanoparticles were able to develop into a ferrite (α-Fe) and α″-Fe16N2 mixture with a superparamagnetic property and high saturated magnetization (SM) of 245 emu g−1 at 950 °C calcination under the protection of carbonization materials (calcined PANI) and other iron-compounds (α″-Fe16N2). The SM of the calcined iron-composites slightly decreases to 232 emu g−1 after staying in the open air for 3 months. The calcined mixture composite can be ground into homogeneous powders without the segregation of the iron and carbon phases in the mortar without significantly losing magnetic activities.
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Huang WY, Jheng LC, Hsieh TH, Ho KS, Wang YZ, Gao YJ, Tseng PH. Calcined Co(II)-Triethylenetetramine, Co(II)- Polyaniline-Thiourea as the Cathode Catalyst of Proton Exchanged Membrane Fuel Cell. Polymers (Basel) 2020; 12:polym12123070. [PMID: 33371521 PMCID: PMC7767545 DOI: 10.3390/polym12123070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/17/2020] [Accepted: 12/21/2020] [Indexed: 02/04/2023] Open
Abstract
Triethylenetetramine (TETA) and thiourea complexed Cobalt(II) (Co(II)) ions are used as cathode catalysts for proton exchanged membrane fuel cells (PEMFCs) under the protection of polyaniline (PANI) which can become a conducting medium after calcination. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) spectra clearly reveal the presence of typical carbon nitride and sulfide bonds of the calcined Nitrogen (N)- or Sulfur (S)-doped co-catalysts. Clear (002) and (100) planes of carbon-related X-ray diffraction patterns are found for co-catalysts after calcination, related to the formation of a conducting medium after the calcination of PANI. An increasing intensity ratio of the D to G band of the Raman spectra reveal the doping of N and S elements. More porous surfaces of co-catalysts are found in scanning electronic microscopy (SEM) micropictures when prepared in the presence of both TETA and thiourea (CoNxSyC). Linear sweep voltammetry (LSV) curves show the highest reducing current to be 4 mAcm−2 at 1600 rpm for CoNxSyC, indicating the necessity for both N- and S-doping. The membrane electrode assemblies (MEA) prepared with the cathode made of CoNxSyC produces the highest maximum power density, close to 180 mW cm−2.
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Affiliation(s)
- Wen-Yao Huang
- Department of Photonics, National Sun Yat-sen University, 70 Lienhai Rd., Kaohsiung 80424, Taiwan;
| | - Li-Cheng Jheng
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan; (L.-C.J.); (T.-H.H.); (Y.-J.G.); (P.-H.T.)
| | - Tar-Hwa Hsieh
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan; (L.-C.J.); (T.-H.H.); (Y.-J.G.); (P.-H.T.)
| | - Ko-Shan Ho
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan; (L.-C.J.); (T.-H.H.); (Y.-J.G.); (P.-H.T.)
- Correspondence: (K.-S.H.); (Y.-Z.W.)
| | - Yen-Zen Wang
- Department of Chemical and Materials Engineering, National Yun-Lin University of Science and Technology, Yun-Lin 64002, Taiwan
- Correspondence: (K.-S.H.); (Y.-Z.W.)
| | - Yi-Jhun Gao
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan; (L.-C.J.); (T.-H.H.); (Y.-J.G.); (P.-H.T.)
| | - Po-Hao Tseng
- Department of Chemical and Materials Engineering, National Kaohsiung University of Science and Technology, 415, Chien-Kuo Road, Kaohsiung 80782, Taiwan; (L.-C.J.); (T.-H.H.); (Y.-J.G.); (P.-H.T.)
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