Induced Superaerophobicity onto a Non-superaerophobic Catalytic Surface for Enhanced Hydrogen Evolution Reaction

Akbar, Kamran,Hussain, Sajjad,Truong, Linh,Roy, Sanjib Baran,Jeon, Jae Ho,Jerng, Sahng-Kyoon,Kim, Minsoo,Yi, Yeonjin,Jung, Jongwan,Chun, Seung-Hyun American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.50

<P>Despite tremendous progress in the development of novel electrocatalysts for hydrogen evolution reaction (HER), the accumulation, of hydrogen gas bubbles produced on the catalyst surface has been rather poorly addressed. The bubbles block the surface of the electrode, thus resulting in poor performance even when excellent electrocatalysts are used. In this study, we show that vertically grown graphene nanohills (VGNHs) possess an excellent capability to quickly disengage the produced hydrogen gas bubbles from the electrode surface, and thus exhibit superaerophobic properties. To compensate for the poor electrolytic properties of graphene toward HER, the graphene surface was modified with WS2 nanoparticles to accelerate the water-splitting process by using this hybrid catalyst (VGNHs-WS2). For comparison purposes, WS2 nanoparticles were also deposited on the flat graphene (FG) surface. Because of its superior superaerophobic properties, VGNHs-WS2 outperformed FG-WS2 in terms of both catalytic activity toward the HER and superaerophobicity. Furthermore, VGNHs-WS2 exhibited a low onset potential (36 mV compared to 288 mV for FG-WS2) and long-term stability in the HER over an extended period of 20 h. This study provides an efficient way to utilize highly conductive and superaerophobic VGNHs as support materials for intrinsic semiconductors, such as WS2, to simultaneously achieve superaerophobicity and high catalytic activity.</P>

WS₂/CoSe₂ heterostructure: A designed structure as catalysts for enhanced hydrogen evolution performance

Hussain, Sajjad,Akbar, Kamran,Vikraman, Dhanasekaran,Liu, Hailiang,Chun, Seung-Hyun,Jung, Jongwan THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.65 No.-

<P><B>Abstract</B></P> <P>The development of hydrogen-evolving catalysts based on transition metal dichalchogenides (TMDs) is receiving a great attention for practical application of water-splitting devices and fuel cells due to their high electrocatalytic activity. Herein, we synthesized tungsten disulfide (WS<SUB>2</SUB>)/cobalt diselenide (CoSe<SUB>2</SUB>) hybrid catalyst for hydrogen evolution reaction (HER). CoSe<SUB>2</SUB> films were first deposited via electrodeposition of Co and followed by selenization process. And, the surface of the synthesized CoSe<SUB>2</SUB> films was covered with WS<SUB>2</SUB> via combined process of sputtering and sulfurization. In acidic media, the WS<SUB>2</SUB>/CoSe<SUB>2</SUB> heterostructure catalyst exhibited fast hydrogen evolution kinetics of onset potential and Tafel slope were at 95mV and 44mVdecade<SUP>−1</SUP>, respectively with the excellent electrocatalytic stability over 20h. WS<SUB>2</SUB>/CoSe<SUB>2</SUB> heterostructure electrode demonstrates an excellent HER activity and long-term stability owing to their abundant active edge sites, and the strong chemical and electronic coupling between the CoSe<SUB>2</SUB> and WS<SUB>2</SUB>.</P> <P><B>Graphical abstract</B></P> <P>WS<SUB>2</SUB>/CoSe<SUB>2</SUB> hybrid structure was implemented to enhance HER electrocatalytic activity. The WS<SUB>2</SUB>/CoSe<SUB>2</SUB> catalyst exhibited low overpotentials of 95mV (@1mAcm<SUP>−2</SUP>) and 160mV (@ 10mAcm<SUP>−2</SUP>), a high exchange current density of ∼1.0×10<SUP>−2</SUP> mAcm<SUP>−2</SUP>, and a small Tafel slope of 44mVdecade<SUP>−1</SUP>. In addition, WS<SUB>2</SUB>/CoSe<SUB>2</SUB> hybrid electrode was stable over 20h of sustained hydrogen production in 0.5M H<SUB>2</SUB>SO<SUB>4</SUB> acidic medium.</P> <P>[DISPLAY OMISSION]</P>

Facile and cost-effective growth of MoS₂ on 3D porous graphene-coated Ni foam for robust and stable hydrogen evolution reaction

Hussain, Sajjad,Vikraman, Dhanasekaran,Truong, Linh,Akbar, Kamran,Rabani, Iqra,Kim, Hyun-Seok,Chun, Seung-Hyun,Jung, Jongwan Elsevier 2019 JOURNAL OF ALLOYS AND COMPOUNDS Vol.788 No.-

<P><B>Abstract</B></P> <P>To replace the costly, noble platinum electrocatalyst, the inexpensive, earth abundant and highly efficient electrocatalysts of layered transition metal dichalcogenides (TMDs) are explored for the hydrogen evolution reaction (HER). This paper describes cost-effective synthesis of 1T-MoS<SUB>2</SUB> on 3D-graphene/Ni foam (NF) via a facile solution bath approach as an electrocatalyst for HER. The improved HER performances were observed due to the 3D-structure of MoS<SUB>2</SUB>/graphene. HER performance of MoS<SUB>2</SUB>/graphene/NF electrocatalyst exposed a superior catalytic performance with the low overpotential (−89 mV vs RHE) to drive the 10 mA cm<SUP>−2</SUP>, steep Tafel slope (45 mV dec<SUP>−1</SUP>), large exchange current density (4.16 × 10<SUP>−1</SUP> mA cm<SUP>−2</SUP>), and robust stability over 18 h. Density functional theory (DFT) calculations also confirmed the reduced Gibbs free energy for H-adsorption (ΔG<SUB>H</SUB>) for MoS<SUB>2</SUB>/graphene compared to MoS<SUB>2</SUB>. The observed results suggest that the 1T-MoS<SUB>2</SUB>/graphene/NF is an interesting alternative to platinum-based catalyst for boosting HER efficiency.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Active electrocatalyst of MoS<SUB>2</SUB> decorated on graphene/NF by chemical route. </LI> <LI> Raman and XRD results confirmed the observation of 1T-MoS<SUB>2</SUB>. </LI> <LI> The robust stability over 18 h with over potential of 89 mV vs RHE was observed. </LI> <LI> DFT calculations explained in terms of density of states for high HER performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A highly sensitive enzymeless glucose sensor based on 3D graphene-Cu hybrid electrodes

Hussain, S.,Akbar, K.,Vikraman, D.,Choi, D. C.,Kim, S.,An, K. S.,Jung, S.,Jung, J. Royal Society of Chemistry 2015 NEW JOURNAL OF CHEMISTRY Vol.39 No.9

WS2/CoSe2 heterostructure: A designed structure as catalysts for enhanced hydrogen evolution performance

Sajjad Hussain,Kamran Akbar,Dhanasekaran Vikraman,Hailiang Liu,천승현,정종완 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.65 No.-

The development of hydrogen-evolving catalysts based on transition metal dichalchogenides (TMDs) is receiving a great attention for practical application of water-splitting devices and fuel cells due to their high electrocatalytic activity. Herein, we synthesized tungsten disulfide (WS2)/cobalt diselenide (CoSe2) hybrid catalyst for hydrogen evolution reaction (HER). CoSe2 films were first deposited via electrodeposition of Co and followed by selenization process. And, the surface of the synthesized CoSe2 films was covered with WS2 via combined process of sputtering and sulfurization. In acidic media, the WS2/CoSe2 heterostructure catalyst exhibited fast hydrogen evolution kinetics of onset potential and Tafel slope were at 95 mV and 44 mV decade−1, respectively with the excellent electrocatalytic stability over 20 h. WS2/CoSe2 heterostructure electrode demonstrates an excellent HER activity and long-term stability owing to their abundant active edge sites, and the strong chemical and electronic coupling between the CoSe2 and WS2.

Impact of waste crumb rubber on concrete performance incorporating silica fume and fly ash to make a sustainable low carbon concrete

Muhammad Akbar,Zahoor Hussain,Pan Huali,Muhammad Imran,Blessen Skariah Thomas 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.85 No.2

The use of environmental-friendly building materials is becoming increasingly popular worldwide. Compared to the normal concrete, rubber-based concrete is considered more durable, environmentally friendly, socially and economically viable. In this investigation, M20 grade concrete was designed and the fine aggregates were replaced with crumb rubber of two different micron sizes (0.221 mm and 0.350 mm). Fly ash (FA) and silica fume (SF) replaces the binder as supplementary cementitious materials at a rate of 0, 5, 10, 15, and 20% by weight. The mechanical properties of concrete including compressive strength, tensile, and flexural strength were determined. The polynomial work expectation validates the response surface approach (RSM) concept for optimizing SF and FA substitution. The maximum compressive strength (22.53 MPa) can be observed for the concrete containing 10% crumb rubber, 15% fly ash and 15% silica fume. The reduced unit weight of the rubberized concrete may be attributed to the lower specific gravity of the rubber particles. Two-way ANOVA with a significance criterion of less than 0.001 has been utilized with modest residual error from the lack of fit and the pure error. The predictive model accurately forecasts the variable-response relationship. Since, the crumb rubber is obtained from wasted tires incorporating FA and SF as a cementitious ingredient, it helps to significantly improve mechanical properties of concrete and reduce environmental degradation.

A vibration-based approach for detecting arch dam damage using RBF neural networks and Jaya algorithms

Zahoor Hussain,Ali Zar,Muhammad Akbar,Bassam A. Tayeh,Zhibin Lin 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.32 No.5

The study presents a new hybrid data-driven method by combining radial basis functions neural networks (RBFNN) with the Jaya algorithm (JA) to provide effective structural health monitoring of arch dams. The novelty of this approach lies in that only one user-defined parameter is required and thus can increase its effectiveness and efficiency, as compared to other machine learning techniques that often require processing a large amount of training and testing model parameters and hyper-parameters, with high time-consuming. This approach seeks rapid damage detection in arch dams under dynamic conditions, to prevent potential disasters, by utilizing the RBF-NNN to seamlessly integrate the dynamic elastic modulus (DEM) and modal parameters (such as natural frequency and mode shape) as damage indicators. To determine the dynamic characteristics of the arch dam, the JA sequentially optimizes an objective function rooted in vibration-based data sets. Two case studies of hyperbolic concrete arch dams were carefully designed using finite element simulation to demonstrate the effectiveness of the RBF-NN model, in conjunction with the Jaya algorithm. The testing results demonstrated that the proposed methods could exhibit significant computational time-savings, while effectively detecting damage in arch dam structures with complex nonlinearities. Furthermore, despite training data contaminated with a high level of noise, the RBF-NN and JA fusion remained the robustness, with high accuracy.

A Routing Overlay for Wireless Sensor Networks with Multiple Services Support

Ali Hammad Akbar,Ahmad Ali Iqbal,Shafique Ahmad Chaudhry,Chaudhary Sajiad Hussain,Ki-Hung KIm 한국차세대컴퓨팅학회 2005 한국차세대컴퓨팅학회 논문지 Vol.1 No.2

Direct synthesis of thickness-tunable MoS₂ quantum dot thin layers: Optical, structural and electrical properties and their application to hydrogen evolution

Vikraman, Dhanasekaran,Akbar, Kamran,Hussain, Sajjad,Yoo, Geonwook,Jang, Ji-Yun,Chun, Seung-Hyun,Jung, Jongwan,Park, Hui Joon Elsevier 2017 Nano energy Vol.35 No.-

<P><B>Abstract</B></P> <P>We report a layer thickness-tunable direct synthesis growth method for bi- to few-layer crystalline molybdenum disulfide (MoS<SUB>2</SUB>) thin layers. For the first time, a facile, cost effective, and mass-scalable direct synthesis approach, based on a chemical bath deposition, is designed for quantum dot(QD)-based MoS<SUB>2</SUB> layers using (NH<SUB>4</SUB>)<SUB>6</SUB>Mo<SUB>7</SUB>O<SUB>24</SUB> and thiourea (CH<SUB>4</SUB>N<SUB>2</SUB>S) as precursors. Using this process, the uniformity of large area thin layer can be retained, and the applicability to various substrates can provide great opportunities in the fabrication of various atomically thin layered structures. The structural and optical properties of the MoS<SUB>2</SUB> QD layers are systematically investigated. Raman, AFM and TEM analyses confirm the formation of continuous and crystalline bi-, tri- and few-layered MoS<SUB>2</SUB>. Their electrical properties are evaluated by bottom-gate FETs, and a field-effect mobility value of ~1.06cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> and a current on/off ratio in the order of ~ 10<SUP>5</SUP> are obtained. Particularly, MoS<SUB>2</SUB> prepared as a thin film consisting QD structures of grains shows novel electrocatalytic property. MoS<SUB>2</SUB> QDs on Au/Si are proven to be excellent electrocatalysts for hydrogen evolution reaction, featured by Tafel slope (94mVdecade<SUP>−1</SUP>), exchange current density (1.91×10<SUP>-1</SUP> mAcm<SUP>−2</SUP>) and long-term durability for 20h. Our approach opens new avenues for the design and synthesis of functional MoS<SUB>2</SUB> layers for energy harvesting.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A layer thickness-tunable direct synthesis growth method for bi- to few-layer crystalline MoS<SUB>2</SUB> thin layers is reported. </LI> <LI> This approach is applicable to various substrates. </LI> <LI> The structural and optical properties of the synthesized MoS<SUB>2</SUB> layers are systematically investigated. </LI> <LI> The electrical properties of the synthesized MoS<SUB>2</SUB> layers are evaluated by bottom-gate FETs. </LI> <LI> MoS<SUB>2</SUB> QDs on Au/Si are proven to be excellent electrocatalysts for hydrogen evolution reaction. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

A Proxy-Enabled Service Discovery Architecture to Find Proximity-Based Services in 6LoWPAN

Chaudhry, S. A.,Do Jung, W.,Hussain, C. S.,Akbar, A. H.,Kim, K.-H. SPRINGER-VERLAG 2006 Lecture Notes in Computer Science Vol.4096 No.-