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Dhara*, S, Kesavamoorthy R, Magudapathy P, Premila M, Panigrahi BK, Nair KGM, Wu CT, Chen KH, Chen LC.  2003.  Quasiquenching size effects in gold nanoclusters embedded in silica matrix. Chem. Phys. Lett.. 370:254-260.
Dhara*, S, Sundaravel B, K.H. Chen, et al.  2004.  Spillout effect in gold nanoclusters embedded in c-Al2O3(0001) matrix. Chem. Phys. Lett.. 399:354-358.
Dhara*, S, Lu C-Y, Nair KGM, Chen KH, Chen C-P, Huang Y-F, David C, Chen LC, Raj B.  2008.  Mechanism of bright red emission in Si nanoclusters. Nanotechnology. 19:395401-(1-5).
Dhara*, S, Wu JJ, Mangama G, Bera S, Magudapathy P, Wu CT, Nair KGM, Kamaruddin M, Yu CC, Yang MH, Liu SC, Tyagi AK, Narashiman SV, Chen LC, Chen KH.  2007.  Long-range ferromagnetic ordering at room temperature in Co+ implanted TiO2 nanorods. Nanotechnology. 18:325705.
Dhara*, S, Chandra S, Magudapathy P, Kalavathi S, Panigrahi BK, Nair KGM, Sastry VS, Hsu CW, Wu CT, Chen KH, Chen LC.  2004.  Blue luminescence of Au nanoclusters embedded in silica matrix. J. Chem. Phys.. 121:12595-12599.
Dhara*, S, Sundaravel B, Nair KGM, Kesavamoorthy R, Valsakumar MC, Rao CTV, Chen LC, Chen KH.  2006.  Ferromagnetism in cobalt doped n-GaN. Appl. Phys. Lett.. 88:173110-(1-3).
Dhara*, S, Das CR, Hsu HC, Chen KH, Chen LC, Raj B, Bhaduri AK, Albert SK, Ray A.  2008.  Recrystallization of epitaxial GaN under indentation. Appl. Phys. Lett.. 92:143114.
Du, HY, Wang CH, Yang CS, Hsu HC, Chang ST, Huang HC, Lai SW, Chen JC, Yu LT, Chen LC, Chen KH.  2014.  A high performance polybenzimidazole-CNT hybrid electrode for high-temperature proton exchange membrane fuel cells. J. of Mater. Chem. . 2:7015-7019.
Du, HY, Yang CS, Hsu H-C, Huang HC, Chang ST, Wang C-H, Chen J-C, Chen KH, Chen LC.  2015.  Pulsed electrochemical deposition of Pt NPs on polybenzimidazole-CNT hybrid electrode for high-temperature proton exchange membrane fuel cells. International Journal of Hydrogen Energy. 40:14398.
Du, H-Y, Wang C-H, Hsu H-C, Chang S-T, Chen U-S, Yen SC, Chen LC, Shih H-C, Chen* KH.  2008.  Controlled platinum nanoparticles uniformly dispersed on nitrogen-doped carbon nanotubes for methanol oxidation. Diamond & Relat. Mater.. 17:535-541.
Du, HY, Wang CH, Hsu HC, Chang ST, Yen SC, Chen LC, Viswanathan B, Chen* KH.  2011.  High performance of catalysts supported by directly grown PTFE-free micro-porous CNT layer in a proton exchange membrane fuel cell. J. Mater. Chem.. 21:2512-2516.
Du, H-Y, Huang Y-F, Wong D, Tseng M-F, Lee Y-H, Wang C-H, Lin C-L, Hoffmann G, Chen K-H, Chen L-C.  2021.  Nanoscale redox mapping at the MoS2-liquid interface, 2021. 12(1):1321. AbstractWebsite

Layered MoS2 is considered as one of the most promising two-dimensional photocatalytic materials for hydrogen evolution and water splitting; however, the electronic structure at the MoS2-liquid interface is so far insufficiently resolved. Measuring and understanding the band offset at the surfaces of MoS2 are crucial for understanding catalytic reactions and to achieve further improvements in performance. Herein, the heterogeneous charge transfer behavior of MoS2 flakes of various layer numbers and sizes is addressed with high spatial resolution in organic solutions using the ferrocene/ferrocenium (Fc/Fc+) redox pair as a probe in near-field scanning electrochemical microscopy, i.e. in close nm probe-sample proximity. Redox mapping reveals an area and layer dependent reactivity for MoS2 with a detailed insight into the local processes as band offset and confinement of the faradaic current obtained. In combination with additional characterization methods, we deduce a band alignment occurring at the liquid-solid interface.

E. N. Konyushenko, Stejskal* J, Trchova M, Hradi J, Kovarova J, Prokes J, Cieslar M, Hwang JY, Chen KH, Sapurina I.  2006.  Multi-wall carbon nanotubes coated with polyaniline. Polymer. 47:5715-5723.
Ebrahimi, M, Samadi M, Yousefzadeh S, Soltani M, Rahimi A, Chou T-chin, Chen L-C, Chen K-H, Moshfegh AZ.  2017.  Improved Solar-Driven Photocatalytic Activity of Hybrid Graphene Quantum Dots/ZnO Nanowires: A Direct Z-Scheme Mechanism, 2017. ACS Sustainable Chemistry & EngineeringACS Sustainable Chemistry & Engineering. 5(1):367-375.: American Chemical Society AbstractWebsite
Fahimi, Z, Moradlou O, Sabbah A, Chen K-H, Chen L-C, Qorbani M.  2022.  Co3V2O8 hollow spheres with mesoporous walls as high-capacitance electrode for hybrid supercapacitor device, 2022. 436:135225. AbstractWebsite

Bimetal oxides are promising materials in the field of energy storage due to their various oxidation states, synergistic interactions among multiple metal species, and stability. In this work, Co3V2O8 hollow spheres are synthesized by a two-step hydrothermal method: (i) synthesis of V2O5 spheres and (ii) partial replacement of V by Co through the Kirkendall effect. As an electrode, it shows an extrinsic pseudocapacitive charge-storage mechanism due to different oxidation states of V and Co ions. Because of the low crystallinity degree of the mesoporous wall and high accessible surface area of hollow spheres, the optimum Co3V2O8 electrode reaches a high specific capacitance of 2376F g−1 at a current density of 2 A g−1, which is more than two times higher than the top reported values, and a rate capability retention of ∼80% at 20 A g−1. Using Co3V2O8, activated carbon, and KOH as positive, negative electrodes, and electrolyte, respectively, a hybrid supercapacitor device presents maximum energy and power densities of 59.2 Wh kg−1 and 36.6 kW kg−1, respectively. Further, the aqueous supercapacitor device shows superior structural and electrochemical stabilities after 10,000 galvanostatic charge–discharge cycles because of the arrays of voids in the orthorhombic crystal structure of Co3V2O8 that can decrease the volume expansion/shrinkage during the intercalation/deintercalation processes. Our results provide a platform for exploring bimetallic Co and V-based oxides, hydroxides, and sulfides nanostructures as promising energy storage materials in the future.

Fang, S-L, Chou T-chin, Samireddi S, Chen K-H, Chen L-C, Chen W-F.  2017.  Enhanced hydrogen evolution reaction on hybrids of cobalt phosphide and molybdenum phosphide, 2017/03/01. Royal Society open science. 4(3):161016161016-161016.: The Royal Society Publishing AbstractWebsite

Production of hydrogen from water electrolysis has stimulated the search of sustainable electrocatalysts as possible alternatives. Recently, cobalt phosphide (CoP) and molybdenum phosphide (MoP) received great attention owing to their superior catalytic activity and stability towards the hydrogen evolution reaction (HER) which rivals platinum catalysts. In this study, we synthesize and study a series of catalysts based on hybrids of CoP and MoP with different Co/Mo ratio. The HER activity shows a volcano shape and reaches a maximum for Co/Mo = 1. Tafel analysis indicates a change in the dominating step of Volmer-Hyrovský mechanism. Interestingly, X-ray diffraction patterns confirmed a major ternary interstitial hexagonal CoMoP(2) crystal phase is formed which enhances the electrochemical activity.

Fang, WC, Huang* JH, Chen LC, Su OYL, Chen KH.  2006.  Effect of temperature annealing on capacitive and structural properties of hydrous ruthenium oxides. J. Power Sources . 160:1506-1510.
Fang, WC, Huang JH, Sun CL, Chen* LC, Papakonstantinou P, Chyan OM, Chen KH.  2006.  Superior electrochemical performance of CNxNTs using TiSi2buffer layer on Si substrates. J. Vac. Sci. Tech.. B24:87-90.
Fang, WC, Huang* JH, Chen LC, Su YO, H.Chen K, Sun CL.  2006.  Carbon nanotubes directly grown on Ti electrodes and enhancement in their electrochemical properties by nitric acid treatment. Electrochemical and Solid-State Lett.. 9:A5.
Fang, WC, Huang* JH, Chen LC, Chen KH, Su OYH.  2007.  Influence of catalyst oxidation on the growth of nitrogen-containing carbonnanotubes for energy generation and storage applications. Diamond Relat. Mater.. 16:1140-1143.
Fang, WC, Huang JH, Sun CL, Chen* KH, Chyan OM, Wu CT, Chen CP, Chen LC.  2007.  Arrayed nanocomposites directly grown on Ti-buffered silicon substrate for miniaturized supercapacitor applications. Electrochem. Comm.. 9:239-244.
Fang, WC, Huang JH, Sun CL, Chen* LC, Papakonstantinou P, Chyan OM, Chen KH.  2006.  Enhanced electrochemical properties of arrayed CNxnanotubes directly grown on Ti-buffered silicon substrates. Electrochemical and Solid State Lett.. 9:A175-A178.
Fang*, WC, Leu MS, Chen KH, Chen LC.  2008.  Ultrafast charging-discharging capacitive property of RuO2nanoparticles on carbon nanotubes using nitrogen incorporation. J. Electrochem. Soc.. 155:K15-K18.
Fang*, WC, Leu MS, Chen KH, Chen LC, Huang JH.  2007.  Effect of structural morphology on electrochemical properties of carbon nanotubes directly grown on Ti foil. Electrochemical and Solid-State Lett.. 10:K60-K62.
Fathabadi, M, Qorbani M, Sabbah A, Quadir S, Huang C-Y, Chen KH, Chen L-C, Naseri N.  2022.  Ultrathin amorphous defective co-doped hematite passivation layer derived via in-situ electrochemical method for durable photoelectrochemical water oxidation, 2022. Journal of Materials Chemistry A. :-.: The Royal Society of Chemistry AbstractWebsite

Although hematite (i.e., α-Fe2O3) has been widely investigated in photoelectrochemical water oxidation studies due to its high theoretical photocurrent density, it still suffers from serious surface charge recombination and low photoelectrochemical stability. Here we report an in-situ electrochemical method to form a uniform and ultrathin (i.e., 3–5 nm) passivation layer all over the porosities of the optimized ~3.2% Ti-doped α-Fe2O3 photoanode. We unveil the amorphous and defective nature of the in-situ derived layer assigning to a high concentration of oxygen vacancy and intercalated potassium atoms there, i.e., the formation of Ti/K co-doped defective α-Fe2O3-x. Owing to the efficient passivation of surface states, alleviated surface-potential fluctuations, and low charge-transfer resistance at the interface, photoanodes show an average of ~60% enhancement in the photoelectrochemical performance, applied bias absorbed photon-to-current efficiency of 0.43%, and Faradaic efficiency of ~88%. Moreover, the passivation layer prevents direct contact between the electrode material and electrolyte, resulting in less degradation and outstanding photoelectrochemical stability with photocurrent retention of ~95% after ~100 hours, albeit by performing several successive in-situ electrochemical passivation processes. This work presents an industrially scalable method to controllably engineer the interfaces of semiconductors–electrolytes with precious metal-free defective hematite-based co-catalysts for sustainable photoelectrochemical solar-to-fuel conversion applications.