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Your search keyword '"Ahmed Waqas"' showing total 121 results
Start Over Author "Ahmed Waqas" Publisher elsevier b.v.
121 results on '"Ahmed Waqas"'

38. Integral 2D/3D structured CoSnO3@MXene/NF as a highly active and stable bifunctional electrocatalyst for alkaline water splitting.

Author

Ullah, Siraj, Ahmed, Waqas, Zeeshan, Muhammad, Hu, Shuozhen, and Zhang, Xinsheng

Subjects
*ELECTROCATALYSTS, *HYDROGEN as fuel, *CATALYTIC activity, *ELECTRIC conductivity, *CHARGE transfer, *ENERGY consumption, *OXYGEN evolution reactions, *WATER electrolysis
Abstract

The pursuit of efficient electrocatalysts for water electrolysis is crucial to advancing the utilization of hydrogen energy. Herein, we designed a robust and active electrocatalyst through synergistically integrating CoSnO 3 nanostructures onto a highly conductive and stable 2D/3D constructed substrate (MXene sheets decorated Ni Foam) without polymer binders. Synergistically, CoSnO 3 demonstrates remarkable bifunctional catalytic activity and stabilizes MXene against spontaneous oxidation. MXene acts as supporting material, enhancing electrical conductivity and preventing aggregation of CoSnO 3. Strong interfacial electronic coupling between the catalyst-substrate significantly facilitates the redistribution of electrons at the interfaces of CoSnO 3 and MXene. The CoSnO 3 @MX/NF(2:1) electrocatalyst achieves overpotentials of 274/387 and 108/376 mV at current densities of 10/500 mA cm−2 for OER and HER, respectively. In a two-electrode water electrolyzer, it delivers a cell voltage of 1.52 V at 10 mA cm−2 and good stability of over 24 h at both 100 and 300 mA cm−2, signifying outstanding performance for water splitting reactions. [Display omitted] • CoSnO 3 @MX/NF is synthesized by a simple hydrothermal post-annealing method. • 2D/3D structure of CoSnO 3 @MX/NF enhances mass/charge transfer and conductivity. • Extensive surface area and numerous catalytically active sites are exposed. • Abundant active sites in the electrocatalyst yield exceptional OER/HER activity. • Good stability of electrocatalyst is found during overall water splitting process. [ABSTRACT FROM AUTHOR]

Published
2024
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39. A novel output feedback consensus control approach for generic linear multi-agent systems under input saturation over a directed graph topology.

Author

Ali, Paghunda Roheela, Rehan, Muhammad, Ahmed, Waqas, Basit, Abdul, and Ahmed, Ijaz

Subjects
DIRECTED graphs, MULTIAGENT systems, LINEAR systems, STATE feedback (Feedback control systems), TOPOLOGY, LYAPUNOV functions
Abstract

This paper considers an output feedback consensus control approach for the generic linear multi-agent systems (MASs) under input saturation over a directed graph. A region of stability-based approach has been established for dealing with the input saturation. A conventional Luenberger observer for estimating the states of followers by themselves and an advanced cooperative observer for estimating the state of leader by followers have been applied for an estimated state feedback control. The stability conditions have been derived by considering a three-term-based combined Lyapunov function. Moreover, computationally simple controller and estimator design conditions have been obtained by resorting to a decoupling approach A set of initial conditions has been investigated to achieve the leader-following consensus of MASs under the input saturation constraint. To the best of our knowledge, an output feedback consensus approach, providing a consensus region, for generic linear MASs under input saturation over directed graphs without requiring the exact state of the leader has been explored for the first time. In contrast to the existing methods, the proposed approach considers an output feedback approach (rather than the state feedback), accounts for both linear and nonlinear saturation regions, applies an estimate of the state of the leader through cooperative observer, and is based on a generalized sector condition for the saturation nonlinearity. In addition, it offers a computationally simple design solution owing to the proposed decoupling method. Simulation results are provided to validate the efficacy of the designed protocol for F-18 aircraft and unmanned ground vehicles. • Output feedback consensus approach with consensus region for linear MASs under input saturation. • A cooperative observer is designed for estimating the leader's state. • The approach allows linear and nonlinear saturation regions via a generalized sector condition. • A region of attraction for the consensus region has been provided. • A simple design condition through a decoupling approach has been revealed over directed graphs. [ABSTRACT FROM AUTHOR]

Published
2024
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