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38. CoOx-NCNT-Supported NiFe-Selenide Nanosheets as an Efficient Bifunctional Electrocatalyst for Water Splitting

Author

Hameed, Arslan, Nisar, Arooj, Nasim, Fatima, Nadeem, Muhammad Amtiaz, and Nadeem, Muhammad Arif

Abstract

Efficient and stable electrocatalysts play a fundamental role in advancing the kinetics of water splitting for clean hydrogen production. Transition-metal selenides have been explored as viable candidates for water splitting due to their high abundance and remarkable activities. In this work, we present a novel and versatile strategy to synthesize a high-performance electrocatalyst (NiFeSe@CoOx-NCNTs) that exhibits excellent electrocatalytic activity for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). NiFeSe@CoOx-NCNTs have been fabricated by the selenization of NiFe-LDH/CoOx-NCNTs which were synthesized by adopting a hydrothermal approach. The resulting material demonstrates an OER overpotential (η) of only 240 mV at 20 mA/cm2, accompanied by a small Tafel value of 59.2 mV/dec. The catalyst also exhibits outstanding electrocatalytic activity toward HER with an η of 145 mV at 20 mA/cm2. The better HER kinetics on the surface of NiFeSe@CoOx-NCNTs is further supported by a small Tafel slope of ∼169 mV/dec. The small charge transfer resistance (Rct) experienced by NiFeSe@CoOx-NCNTs during both the OER and HER is an indication of the fast movement of active species, which contributes to the enhanced electrocatalytic activity. The high stability of NiFeSe@CoOx-NCNTs for a period of 15 h makes the electrocatalyst an appealing candidate for energy conversion systems.

Published
2024
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39. Tranexamic acid for acute gastrointestinal bleeding (the HALT-IT trial): statistical analysis plan for an international, randomised, double-blind, placebo-controlled trial

Author

Brenner, Amy, Afolabi, Adefemi, Ahmad, Syed Masroor, Arribas, Monica, Chaudhri, Rizwana, Coats, Timothy, Cuzick, Jack, Gilmore, Ian, Hawkey, Christopher, Jairath, Vipul, Javaid, Kiran, Kayani, Aasia, Mutti, Muttiullah, Nadeem, Muhammad Arif, Shakur-Still, Haleema, Stanworth, Simon, Veitch, Andrew, Roberts, Ian, and HALT-IT Trial Collaborators

Published
2019
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49. Understanding the mechanism and synergistic interaction of cobalt-based electrocatalysts containing nitrogen-doped carbon for 4 e− ORR.

Author

Nasim, Fatima and Nadeem, Muhammad Arif

Abstract

Considering that the cathodic oxygen reduction reaction (ORR) is sluggish, it is necessary to develop efficient and durable catalysts to accelerate this reaction. Furthermore, the high cost and low abundance of Pt, which is the benchmark catalyst for the cathodic ORR, limit its widespread applications. Among the transition metals, cobalt-based materials have shown significant advancement for the reduction of oxygen molecules, which has been proven by both experimental and theoretical investigations. The high inherent catalytic ability of cobalt among the first row transition metals is the key descriptor for the widespread research in this area. Herein, we review the recent advancements in cobalt-based electrocatalysts supported on nitrogen-doped carbon towards the selective 4 e− reduction of oxygen molecules with enhanced operational durability. Furthermore, we highlight the relationship between theory and experiment to investigate the fundamental mechanism of these electrocatalysts. Finally, we present perspectives on suitable approaches for interpreting the mechanism of cobalt-based nitrogen-doped carbon towards the ORR. [ABSTRACT FROM AUTHOR]

Published
2023
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50. Synergistic Effect of Pd Co-Catalyst and rGO–TiO 2 Hybrid Support for Enhanced Photoreforming of Oxygenates.

Author

Majeed, Imran, Arif, Ayesha, Idrees, Afifa, Ullah, Hafeez, Ali, Hassan, Mehmood, Arshad, Rashid, Ashi, Nadeem, Muhammad Arif, and Nadeem, Muhammad Amtiaz

Subjects
HYDROGEN as fuel, STEAM reforming, ELECTRON transport, INTERSTITIAL hydrogen generation, GRAPHENE oxide
Abstract

Photoreforming biomass-derived waste such as glycerol into hydrogen fuel is a renewable hydrogen generation technology that has the potential to become important due to unavoidable CO2 production during methane steam reforming. Despite tremendous efforts, the challenge of developing highly active photocatalysts at a low cost still remains elusive. Here, we developed a novel photocatalyst with a hybrid support comprising reduced graphene oxide (rGO) and TiO2 nanorods (TNR). rGO in the hybrid support not only performed as an excellent scavenger of electrons from the semiconductor conduction band due to its suitable electrochemical potential, but also acted as an electron transport highway to the metal co-catalyst, which otherwise is not possible by simply increasing metal loading due to the shadowing effect. A series of hybrid supports with different TNR and rGO ratios were prepared by the deposition method. Pd nanoparticles were deposited over hybrid support through the chemical reduction method. Pd/rGO-TNRs photocatalyst containing 4 wt.% rGO contents in the support and 1 wt.% nominal Pd loading demonstrated hydrogen production activity ~41 mmols h−1g−1, which is 4 and 40 times greater than benchmark Au/TiO2 and pristine P25. The findings of this works provide a new strategy in optimizing charge extraction from TiO2, which otherwise has remained impossible due to a fixed tradeoff between metal loading and the detrimental shadowing effect. [ABSTRACT FROM AUTHOR]

Published
2023
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