Catalysis and Reaction Engineering Commons^™

(Co,Ni,Mn,Cu,Zn)O High-Entropy Oxide Nanotubes As Efficient Bifunctional Electrocatalyst For Oxygen Evolution And Hydrazine Oxidation Reactions, Pan-Yan Chen, Wan-Wan Wu, Heng Bian, Wei-Wei Li, Xin-Sheng Zhao, Lu Wei

Journal of Electrochemistry

High-entropy oxides (HEOs) present significant scientific challenges in both design and synthesis due to their multielement and high-entropy nature, which involves complex combinations of multiple metal cations and oxygen anions, typically arranged in equimolar ratios to achieve structural stability. Herein, one-dimensional (Co,Ni,Mn,Cu,Zn)O high-entropy oxide nanotubes (HEO-NTs) are fabricated by means of a gradient electrospinning strategy with a tailored polyvinyl alcohol (PVA) molecular weight distribution and controlled pyrolysis. Benefiting from the HEO features and the synergistic effect of multicomponent sites, the as-synthesized (Co,Ni,Mn,Cu,Zn)O HEO-NTs exhibit exceptional bifunctional electrocatalytic activity for the oxygen evolution and hydrazine oxidation reactions (OER/HzOR). This study offers …

Series Reports From Professor Wei’S Group Of Chongqing University: Advancements In Electrochemical Energy Conversions (2/4): Report 2: High-Performance Water Splitting Electrocatalysts, Ling Zhang, Wang-Yang Wu, Qiu-Yue Hu, Shi-Dan Yang, Li Li, Rui-Jin Liao, Zi-Dong Wei

Journal of Electrochemistry

The unavailability of high-performance and cost-effective electrocatalysts has impeded the large-scale deployment of alkaline water electrolyzers. Professor Zidong Wei’s group has focused on resolving critical challenges in industrial alkaline electrolysis, particularly elucidating hydrogen and oxygen evolution reaction (HER/OER) mechanisms while addressing the persistent activity-stability trade-off. This review summarizes their decade-long progress in developing advanced electrodes, analyzing the origins of sluggish alkaline HER kinetics and OER stability limitations. Professor Wei proposes a unifying “12345 Principle” as an optimization framework. For HER electrocatalysts, they have identified that metal/metal oxide interfaces create synergistic “chimney effect” and “local electric field enhancement effect”, enhancing selective …

Ionic Liquid Enhanced Proton Transfer For Neutral Oxygen Evolution Reaction, Ming-Xing Chen, Nian Liu, Zi-He Dua, Jing Qi, Rui Cao

Journal of Electrochemistry

The development of highly active catalyst in pH-neutral media for oxygen evolution reaction (OER) is critical in the field of renewable energy storage and conversion. Nevertheless, the slow kinetics of proton-coupled electron transfer (PCET) hinders the overall OER efficiency. Herein, we report an ionic liquid (IL) modified CoSn(OH)₆ nanocubes (denoted as CoSn(OH)₆-IL), which could be prepared through a facile strategy. The modified IL would not change the structural characteristics of CoSn(OH)₆, but could effectively regulate the local proton activity near the active sites. The CoSn(OH)₆-IL exhibited higher intrinsic OER performances than the pristine …

Microplate-Like Metal Pyrophosphate Engineered On Ni-Foam Towards Multifunctional Electrode Material For Energy Conversion And Storage, Rishabh Srivastava

Electronic Theses & Dissertations

High clean energy demand, dire need for sustainable development, and low carbon footprints are the few intuitive challenges, leading researchers to aim for research and development for high-performance energy devices. The development of materials used in energy devices is currently focused on enhancing the performance, electronic properties, and durability of devices. Tunning the attributes of transition metals using pyrophosphate (P₂O₇) ligand moieties can be a promising approach to meet the requirements of energy devices such as water electrolyzers and supercapacitors, although such a material’s configuration is rarely exposed for this purpose of study.

Herein, we grow …

Preparation And Electrocatalytic Performance Of Feni-Cop/Nc Bifunctional Catalyst, Si-Miao Liu, Jing-Jiao Zhou, Shi-Jun Ji, Zhong-Sheng Wen

Journal of Electrochemistry

Rechargeable zinc-air batteries have gradually attracted much attention worldwide due to their high capacity, high energy density and low price. Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) correspond to the charging and discharging processes in rechargeable zinc-air battery, respectively. At present, commercial Pt/C and IrO₂ catalysts hinder the large-scale application of zinc-air batteries due to low reserves, high prices and poor stability. Therefore, exploring high performance, low cost and high stability with dual functional catalysts is important for the development of rechargeable zinc-Air batteries. The metal-organic frameworks (MOFs) have high specific surface area, structural stability, good catalytic …

Recent Development Of Low Iridium Electrocatalysts Toward Efficient Water Oxidation, Jing Ni, Zhao-Ping Shi, Xian Wang, Yi-Bo Wang, Hong-Xiang Wu, Chang-Peng Liu, Jun-Jie Ge, Wei Xing

Journal of Electrochemistry

Developing high-performance and low-cost electrocatalysts for oxygen evolution reaction (OER) is the key to implementing polymer electrolyte membrane water electrolyzer (PEMWE) for hydrogen production. To date, iridium (Ir) is the state-of-the-art OER catalyst, but still suffers from the insufficient activity and scarce earth abundance, which results in high cost both in stack and electricity. Design low-Ir catalysts with enhanced activity and stability that can match the requirements of high current and long-term operation in PEMWE is thus highly desired, which necessitate a deep understanding of acidic OER mechanisms, unique insights of material design strategies, and reliable performance evaluation norm, especially …

The Rapid Preparation Of Efficient Mofeco-Based Bifunctional Electrocatalysts Via Joule Heating For Overall Water Splitting, Ao Zhou, Wei-Jian Guo, Yue-Qing Wang, Jin-Tao Zhang

Journal of Electrochemistry

Water electrolysis is an available way to obtain green hydrogen. The development of highly efficient electrocatalysts is a current research hotspot for water splitting, but it remains challenging. Herein, we demonstrate the synthesis of a robust bifunctional multi-metal electrocatalysts toward water splitting via the rapid Joule-heating conversion of metal precursors. The composition and morphology were well regulated via altering the ratio of metal precursors. In particular, the trimetal MoC/FeO/CoO/carbon cloth (CC) electrode revealed the outstanding bifunctional electrocatalytic performance due to the unique composition and large electrochemical active surface area. Typically, the MoC/FeO/CoO/CC catalyst needed low overpotentials of 121 and 268 …

Surface Structure Engineering Of Feni-Based Pre-Catalyst For Oxygen Evolution Reaction: A Mini Review, Jia-Xin Li, Li-Gang Feng

Journal of Electrochemistry

Nitrite, a widespread raw material, is harmful to human health for long-term consumption. At present, the detection methods of nitrite mainly include chemical analysis, fluorescence, ultraviolet spectrophotometry and chromatography. These methods have ideal sensitivity and selectivity, but also have some characteristics: cumbersome operation, expensive equipment and professional personnel. Therefore, the development of a simple and sensitive nitrite assay is of great significance. In this paper, the Au/rGO/FeOOH composite materials, which revealed good synergistic catalytic performance among the three elements in the composite, were prepared by simple hydrothermal method and reduction method for the first time with large specific surface area …

Analyzing The Surface Chemistry Of Ni-Fe Hydroxide Alloy Nanoparticles As Catalysts For The Oxygen Evolution Reaction By X-Ray Photoelectron Spectroscopy Analysis, Lauren B. Shepard

Chemical Engineering Undergraduate Honors Theses

Water electrolysis has been proposed as a renewable source of hydrogen, a possible replacement to harmful fossil fuels. This process can be broken down into two half reactions, the hydrogen evolution reaction and the oxygen evolution reaction. Because the oxygen evolution reaction has slow kinetics and a high overpotential to overcome, a catalyst is needed to speed up the kinetics and ensure faster and more efficient production of molecular hydrogen. The use of Ni-Fe hydroxide alloy nanoparticles as a catalyst has been shown to significantly improve the efficiency of the reaction by decreasing the overpotential, making the process more energy …

In-Situ/Operando57Fe Mössbauer Spectroscopic Technique And Its Applications In Nife-Based Electrocatalysts For Oxygen Evolution Reaction, Jafar Hussain Shah, Qi-Xian Xie, Zhi-Chong Kuang, Ri-Le Ge, Wen-Hui Zhou, Duo-Rong Liu, Alexandre I. Rykov, Xu-Ning Li, Jing-Shan Luo, Jun-Hu Wang

Journal of Electrochemistry

The development of highly efficient and cost-effective electrocatalysts for the sluggish oxygen evolution reaction (OER) remains a significant barrier to establish effective utilization of renewable energy storage systems and water splitting to produce clean fuel. The current status of the research in developing OER catalysts shows that NiFe-based oxygen evolution catalysts (OECs) have been proven as excellent and remarkable candidates for this purpose. But it is critically important to understand the factors that influence their activity and underlying mechanism for the development of state-of-the-art OER catalysts. Therefore, the development of in-situ/operando characterizations is urgently required to detect key intermediates along …

Recent Progress In Bifunctional Catalysts For Zinc-Air Batteries, Neng-Neng Xu, Jin-Li Qiao

Journal of Electrochemistry

Zinc-air battery has attracted great attention from researchers due to its high energy density and power density, which is expected to be widely used in energy conversion and storage. Air electrode as the core area of oxygen catalytic reaction is the focus of the entire zinc-air battery research. Recently, many research achievements have been made in non-noble metal bifunctional catalysts/electrodes with high activity, low cost and abundant species. In this review, we mainly focus on the reaction mechanism and the recent progress in non-noble metal oxide catalyst, carbon-based catalyst, and carbon-based transition metal compound composite and self-supporting electrode. In addition, …

Preparations Of Nickel-Iron Hydroxide/Sulfide And Their Electrocatalytic Performances For Overall Water Splitting, Hang-Shuo Lu, Xiao-Bo He, Feng-Xiang Yin, Guo-Ru Li

Journal of Electrochemistry

The Ni-Fe/Ti oxygen evolution electrode was prepared by electrodeposition on a titanium mesh substrate. Then, the as prepared Ni-Fe/Ti electrode was used to derive the Ni-Fe-S/Ti hydrogen evolution electrode through solid phase sulfuration. The effects of the molar ratio of Ni²⁺ to Fe³⁺ in the electrolyte and the amount of thiourea on the structures and electrochemical performances of Ni-Fe/Ti and Ni-Fe-S/Ti electrodes were investigated. The results show that the oxygen evolution performance of Ni-Fe/Ti electrode was first increased and then decreased with the increase of nickel ion content in the electrolyte. The Ni9Fe1/Ti electrode exhibited the best oxygen …

Recent Advances In Non-Noble Metal Nanomaterials For Oxygen Evolution Electrocatalysis, Dan-Dan Zhao, Nan Zhang, Ling-Zheng Bu, Qi Shao, Xiao-Qing Huang

Journal of Electrochemistry

Hydrogen is a kind of renewable energies with the merits of environmentally friendly, abundance and high weight energy density, which can replace the fossil energy. The electrolysis of water is regarded as the most effective way to generate hydrogen. Owing to the sluggish kinetics and large overpotential of the anode oxygen evolution reaction (OER), the efficiency of the cathode hydrogen evolution reaction is greatly limited. Therefore, it is highly desirable to explore efficient, stable and low cost electrocatalysts to reduce the overpotential of OER and improve the efficiency of hydrogen evolution. Based on the natural characteristics of non-noble metal catalysts …

Design Strategies Toward Highly Active Electrocatalysts For Oxygen Evolution Reaction, Tang Tang, Wen-Jie Jiang, Shuai Niu, Jin-Song Hu

Journal of Electrochemistry

Electrocatalytic water splitting is pivotal for efficient and economical production of hydrogen and oxygen gasses. However, the efficiency of the whole device is largely limited by the oxygen evolution reaction (OER) at the anode due to its sluggish kinetics. Thus, it is imperative to develop inexpensive, highly active OER catalysts to lower the reaction barriers. By examining the underlying critical factors for OER performance, this review outlines general principles for designing efficient nanosized OER catalysts, including (1) enhancing the intrinsic activity of active site by electronic modulation, crystallinity modulation, phase control, defect engineering and spin state engineering; (2) designing appropriate …

Highly Crystalline Nickel Borate Nanorods As Oxygen Evolution Reaction Electrocatalysts, Xi Xu, Juan Liu, Hua-Zong Wu, Wen-Jie Jiang

Journal of Electrochemistry

Hydrogen energy, a kind of clean and renewable energy, is considered to be the solution to the problems of energy crisis and environmental deterioration. Electrochemical water splitting is an efficient and promising technology for the production of high-purity hydrogen. However, oxygen evolution reaction (OER) at the anode of water electrolyzer limits the efficiency of water splitting due to the high overpotential. Therefore, the challenges still remain for the exploration of highly active, stable and low-cost catalysts with superior activity for OER. Herein, nickel borate nanorods with high crystallinity were prepared via high-temperature calcination. The as-obtained nickel borate nanorods with 2 …

Electrocatalytic Properties Of Ni-Fe Basedalloys Toward Oxygen Evolution Reaction, Xiaodan Cui

LSU Doctoral Dissertations

In this dissertation, laser-based manufacturing was applied to develop NiFe-based alloys, with focus on their electrochemical characteristics toward oxygen evolution reaction during water electrocatalysis. The targeted electrocatalysts were designed by combining catalysis principles of absorption energy, electronic effect and geometry effect. Firstly, a one-step laser-based manufacturing method was applied to prepare a thin layer of NiFe-based electrodes with varied Ni to Fe ratios to replace high-cost noble metals as the electrocatalyst for oxygen evolution reaction (OER). Since each Ni has 0.6 d-vacancy and each Fe atom has 2.2 d-vacancies. The alloying of Ni-Fe allows electrons flowing from Ni to Fe, …

Fabrication Of Mnox/Mwcnts-Gc Nanocatalyst For Oxygen Evolution Reaction, Islam M. Al-Akraa Dr., Yaser M. Asal Mr, Amr M. Arafa Eng.

Chemical Engineering

Manganese oxide (MnOx) and multiwalled carbon nanotubes (MWCNTs) are intended to modify the GC electrode for oxygen evolution reaction (OER). Optimization of MnOx loading is carried out and the deposition of 55 cycles was sufficient to obtain the highest activity toward OER. The stability of the catalyst is enhanced by the addition of MWCNTs. As a result, an amount of 22 kWh/Kg of O2 of energy is saved. Several techniques including cyclic voltammetry, linear sweep voltammetry, chronoamperometry, chronopotentiometry, field-emission scanning electron microscopy, and energy dispersive X-ray spectroscopy will be combined to track the catalyst activity and to determine its morphology …

Comparative Studies Of Fe, Ni, Co And Their Bimetallic Nanoparticles For Electrochemical Water Oxidation, Maduraiveeran Govindhan, Brennan Mao, Aicheng Chen

Journal of Electrochemistry

The design of efficient, durable, and earth-abundant electrocatalysts via environmentally compatible strategies for the oxygen evolution reaction (OER) is a vital for energy conversion processes. Herein we report a facile approach for the fabrication of low-cost and earth abundant metal catalysts, including iron (Fe), nickel (Ni), cobalt (Co), CoNi, and CoFe nanoparticles (NPs) on titanium (Ti) substrates through a one-step electrochemical deposition. Field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) spectrocopy, X-ray photoelectron spectroscopy (XPS), and electrochemical techniques were employed to characterize these nanoparticles. Our electrochemical results revealed that among the five synthesized nanomaterials, the …

Mini-Review: Possible Applications Of Scanning Electrochemical Microscopy (Secm) In Characterizations Of Oxygen Reduction Reaction And Oxygen Evolution Reaction, Xing-Xing Chen

Journal of Electrochemistry

Scanning electrochemical microscopy (SECM) has been proved to be a unique technique for combinatorial screening of localized phenomena for different electrocatalysts potentially used in new energy conversion and storage systems. This mini-review provides a brief summary of different SECM working modes, such as direct mode, feedback mode, generation-collection mode, redox competition mode and noise mode, which are especially applied for characterizing the oxygen reactions. Particularly, a series of important development in SECM screening of electrocatalysts for oxygen reduction reaction and oxygen evolution reaction from the author and W. Schuhmann’s group in Germany has been highlighted and overviewed. Finally, some prospects …

Preparation And Properties Of Binary Oxides CoXCr1-XO3/2 Electrocatalysts For Oxygen Evolution Reaction, Tai-Lai Yang, Wen-Yan Dong, Hui-Min Yang, Li Zhang, Zhen-Hai Liang

Journal of Electrochemistry

Binary metal mixed oxides of Co and Cr with nominal compositional formulas, Co_xCr_1-xO_3/2 (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0), were obtained by thermal decomposition method. The morphologies, crystal forms and valence states of the catalyst powders were analyzed by SEM, XRD and XPS, respectively. And the electrochemical properties, overpotentials and stabilities of Co_xCr_1-xO_3/2 electrodes for oxygen evolution reaction (OER) in an alkaline solution were evaluated by linear sweep voltammetry (LSV), staircase voltammetry and chronoamperometry, respectively. The results indicated that the mixtures of Co₃O₄ and eskolaite-Cr_{2 …}

Preparation, Structure, And Cv Study Of The Supported Ptruir/Tic Electrocatalysts For Oxygen Electrodes, Sheng Sui, Li-Rong Ma

Journal of Electrochemistry

The PtRuIr/TiC electrocatalysts were prepared by method of reduction and deposition on TiC powders as supports together with ultrasonic wave dispersion.The sampls were characterized by BET surface area,scanning electron microscope,X-ray diffraction,and cyclic voltammetry techniques.The active components of Pt,Ru,and Ir particles(2.6%Pt,1.3%Ru,16%Ir,and 80%TiC,by mass) were mainly dispersed on the outer surface of the TiC supports,which structures were in favor of fine variable crystallites.It was found that the electrochemical performance of the PtRuIr/TiC electrodes was about three times as that of the unsupported electrocatalysts with the same active compositions for oxygen evolution reaction.After 120 times of CV cycles,there was almost no PtRuIr/TiC dissolving …