scholarly journals Role of Co in the Electrocatalytic Activity of Monolayer Ternary NiFeCo-Double Hydroxide Nanosheets for Oxygen Evolution Reaction

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 207
Author(s):  
Ye Li ◽  
Dan Zhao ◽  
Yue Shi ◽  
Zhicheng Sun ◽  
Ruping Liu
Keyword(s):  
Oxygen Evolution ◽  
Water Oxidation ◽  
Density Functional ◽  
Chemical Properties ◽  
Functional Materials ◽  
Highly Active ◽  
Coordination Sites ◽  
Catalytic Active Site ◽  
Monolayer Nanosheets ◽  
Double Hydroxide

Monolayer nanosheets have gained significant attention as functional materials and also in photo/electrocatalysis due to their unique physical/chemical properties, abundance of highly exposed coordination sites, edges, and corner sites, motivating the pursuit of highly active monolayer nanosheets. NiFe-based layered double hydroxide (NiFe-LDH) nanosheets have been regarded as the most efficient electrocatalysis for oxygen evolution. However, the limited catalytic active site and the stacking layer limited the performance. Therefore, by introducing highly electroactive Co ions into monolayer NiFe-LDH, the obtained ternary NiFeCo-LDH monolayer structure possessed an increased concentration of defect (oxygen and metal vacancies), providing enough unsaturated coordination sites, benefitting the electrocatalytic water oxidation, as also explained by the density functional theory (DFT). This work reported an efficient strategy for the synthesis of ternary monolayer LDH in the application of energy conversion and storage.

Operando Unraveling Photothermal-Promoted Dynamic Active Sites Generation in Spinel NiFe2O4 for Oxygen Evolution

2020 ◽  
Author(s):  
Likun Gao ◽  
Xun Cui ◽  
Zewei Wang ◽  
Christopher Sewell ◽  
Zili Li ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Surface Reconstruction ◽  
Water Oxidation ◽  
Active Sites ◽  
Density Functional ◽  
Diblock Copolymers ◽  
High Current Density ◽  
Active Surface ◽  
Photothermal Effect ◽  
Highly Active

Abstract The ability to develop highly active and low-cost electrocatalysts represents an important endeavor toward accelerating sluggish water-oxidation kinetics. Herein, we report, for the first time, the implementation and unravelling of photothermal effect of spinel nanoparticles (NPs) on promoting dynamic active sites generation to markedly enhance their oxygen evolution reaction (OER) activity via an integrated operando Raman and density functional theory (DFT) study. Specifically, NiFe2O4 (NFO) NPs are first synthesized by capitalizing on amphiphilic star-like diblock copolymers as nanoreactors. Upon the NIR light irradiation, the photothermal heating of the NFO-based electrode progressively raises the temperature, accompanied by a marked decrease of overpotential. Accordingly, only an overpotential of 309 mV is required to yield a high current density of 100 mA cm-2, greatly lower than recently-reported earth-abundant electrocatalysts. More importantly, photothermal effect of NFO NPs not only significantly reduces the activation energy necessitated for water splitting, but also facilitates surface reconstruction into high-active oxyhydroxides at lower potential (1.36 V) under OER conditions, as revealed by operando Raman spectra-electrochemistry. Moreover, the DFT calculation corroborates that these reconstructed (Ni,Fe)oxyhydroxides are electrocatalytically active sites as the kinetics barrier is largely reduced over pure NFO without surface reconstruction. Given the diversity of materials (metal oxides, sulfides, phosphides, etc.) possessing the photo-to-thermal conversion, this effect may thus provide a unique and robust platform to boost highly-active surface species in nanomaterials for fundamental understanding of enhanced performance that may underpin future advances in electrocatalysis, photocatalysis, solar energy conversion and renewable energy production.  

scholarly journals Operando unraveling photothermal-promoted dynamic active-sites generation in NiFe2O4 for markedly enhanced oxygen evolution

2021 ◽  
Vol 118 (7) ◽  
pp. e2023421118
Author(s):  
Likun Gao ◽  
Xun Cui ◽  
Zewei Wang ◽  
Christopher D. Sewell ◽  
Zili Li ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Surface Reconstruction ◽  
Water Oxidation ◽  
Active Sites ◽  
Density Functional ◽  
Diblock Copolymers ◽  
High Current Density ◽  
Infrared Light ◽  
Photothermal Effect ◽  
Highly Active

The ability to develop highly active and low-cost electrocatalysts represents an important endeavor toward accelerating sluggish water-oxidation kinetics. Herein, we report the implementation and unraveling of the photothermal effect of spinel nanoparticles (NPs) on promoting dynamic active-sites generation to markedly enhance their oxygen evolution reaction (OER) activity via an integrated operando Raman and density functional theory (DFT) study. Specifically, NiFe2O4 (NFO) NPs are first synthesized by capitalizing on amphiphilic star-like diblock copolymers as nanoreactors. Upon the near-infrared light irradiation, the photothermal heating of the NFO-based electrode progressively raises the temperature, accompanied by a marked decrease of overpotential. Accordingly, only an overpotential of 309 mV is required to yield a high current density of 100 mA cm−2, greatly lower than recently reported earth-abundant electrocatalysts. More importantly, the photothermal effect of NFO NPs facilitates surface reconstruction into high-active oxyhydroxides at lower potential (1.36 V) under OER conditions, as revealed by operando Raman spectroelectrochemistry. The DFT calculation corroborates that these reconstructed (Ni,Fe)oxyhydroxides are electrocatalytically active sites as the kinetics barrier is largely reduced over pure NFO without surface reconstruction. Given the diversity of materials (metal oxides, sulfides, phosphides, etc.) possessing the photo-to-thermal conversion, this effect may thus provide a unique and robust platform to boost highly active surface species in nanomaterials for a fundamental understanding of enhanced performance that may underpin future advances in electrocatalysis, photocatalysis, solar-energy conversion, and renewable-energy production.

Controllable growth of graphdiyne layered nanosheets for high-performance water oxidation

2021 ◽  
Author(s):  
Shuya Zhao ◽  
Yurui Xue ◽  
Zhongqiang Wang ◽  
Zhiqiang Zheng ◽  
Xiaoyu Luan ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
High Performance ◽  
Low Cost ◽  
Highly Active ◽  
Controllable Growth

Developing highly active, stable and low-cost electrocatalysts capable of an efficient oxygen evolution reaction (OER) is urgent and challenging.

Amorphous NiFe layered double hydroxide nanosheets decorated on 3D nickel phosphide nanoarrays: a hierarchical core–shell electrocatalyst for efficient oxygen evolution

2018 ◽  
Vol 6 (28) ◽  
pp. 13619-13623 ◽  
Author(s):  
Luo Yu ◽  
Haiqing Zhou ◽  
Jingying Sun ◽  
Ishwar Kumar Mishra ◽  
Dan Luo ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Layered Double Hydroxide ◽  
Water Oxidation ◽  
Core Shell ◽  
Nickel Phosphide ◽  
Double Hydroxide

Amorphous NiFe LDH nanosheets were decorated on nickel phosphide nanoarrays to form a 3D core–shell electrocatalyst for efficient water oxidation.

scholarly journals Highly active oxygen evolution integrated with efficient CO2 to CO electroreduction

2019 ◽  
Vol 116 (48) ◽  
pp. 23915-23922 ◽  
Author(s):  
Yongtao Meng ◽  
Xiao Zhang ◽  
Wei-Hsuan Hung ◽  
Junkai He ◽  
Yi-Sheng Tsai ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Water Oxidation ◽  
Iron Hydroxide ◽  
Fuel Efficiency ◽  
Cell Voltage ◽  
Electrical Energy ◽  
Reduction Reaction ◽  
Faradaic Efficiency ◽  
Nickel Iron ◽  
Highly Active

Electrochemical reduction of CO2 to useful chemicals has been actively pursued for closing the carbon cycle and preventing further deterioration of the environment/climate. Since CO2 reduction reaction (CO2RR) at a cathode is always paired with the oxygen evolution reaction (OER) at an anode, the overall efficiency of electrical energy to chemical fuel conversion must consider the large energy barrier and sluggish kinetics of OER, especially in widely used electrolytes, such as the pH-neutral CO2-saturated 0.5 M KHCO3. OER in such electrolytes mostly relies on noble metal (Ir- and Ru-based) electrocatalysts in the anode. Here, we discover that by anodizing a metallic Ni–Fe composite foam under a harsh condition (in a low-concentration 0.1 M KHCO3 solution at 85 °C under a high-current ∼250 mA/cm2), OER on the NiFe foam is accompanied by anodic etching, and the surface layer evolves into a nickel–iron hydroxide carbonate (NiFe-HC) material composed of porous, poorly crystalline flakes of flower-like NiFe layer-double hydroxide (LDH) intercalated with carbonate anions. The resulting NiFe-HC electrode in CO2-saturated 0.5 M KHCO3 exhibited OER activity superior to IrO2, with an overpotential of 450 and 590 mV to reach 10 and 250 mA/cm2, respectively, and high stability for >120 h without decay. We paired NiFe-HC with a CO2RR catalyst of cobalt phthalocyanine/carbon nanotube (CoPc/CNT) in a CO2 electrolyzer, achieving selective cathodic conversion of CO2 to CO with >97% Faradaic efficiency and simultaneous anodic water oxidation to O2. The device showed a low cell voltage of 2.13 V and high electricity-to-chemical fuel efficiency of 59% at a current density of 10 mA/cm2.

Graphene/Ni–Fe layered double-hydroxide composite as highly active electrocatalyst for water oxidation

2016 ◽  
Vol 74 ◽  
pp. 441-446 ◽  
Author(s):  
Dao-cheng Xia ◽  
Lei Zhou ◽  
Shi Qiao ◽  
Yalin Zhang ◽  
Di Tang ◽  
...  
Keyword(s):  
Layered Double Hydroxide ◽  
Water Oxidation ◽  
Highly Active ◽  
Double Hydroxide

Enhanced oxygen evolution on visible light responsive TaON photocatalysts co-loaded with highly active Ru species for IO3− reduction and Co species for water oxidation

2017 ◽  
Vol 1 (4) ◽  
pp. 748-754 ◽  
Author(s):  
Yukari Iwase ◽  
Osamu Tomita ◽  
Masanobu Higashi ◽  
Ryu Abe
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Water Oxidation ◽  
Redox Couple ◽  
Highly Active ◽  
One Step ◽  
Type Water ◽  
Ru Species

Loading an appropriate cocatalyst significantly enhances the activity of semiconductor photocatalysts in both conventional one-step water splitting and Z-scheme-type water splitting with a redox couple.

scholarly journals Modeling the Catalyst Activation Step in a Metal–Ligand Radical Mechanism Based Water Oxidation System

Inorganics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 62 ◽  
Author(s):  
Nitish Govindarajan ◽  
Evert Jan Meijer
Keyword(s):  
Water Oxidation ◽  
Density Functional ◽  
Radical Mechanism ◽  
Catalyst Activation ◽  
Activation Barriers ◽  
Radical Coupling ◽  
Rate Determining Step ◽  
Highly Active ◽  
Solvent Molecules ◽  
Metal Ligand

Designing catalysts for water oxidation (WOCs) that operate at low overpotentials plays an important role in developing sustainable energy conversion schemes. Recently, a mononuclear ruthenium WOC that operates via metal–ligand radical coupling pathway was reported, with a very low barrier for O–O bond formation, that is usually the rate-determining step in most WOCs. A detailed mechanistic understanding of this mechanism is crucial to design highly active oxygen evolution catalysts. Here, we use density functional theory based molecular dynamics (DFT-MD) with an explicit description of the solvent to investigate the catalyst activation step for the [Ru(bpy) 2 (bpy–NO)] 2 + complex, that is considered to be the rate-limiting step in the metal–ligand radical coupling pathway. We find that a realistic description of the solvent environment, including explicit solvent molecules and thermal motion, is crucial for an accurate description of the catalyst activation step, and for the estimation of the activation barriers.

NixCu1−x/CuO/Ni(OH)2 as highly active and stable electrocatalysts for oxygen evolution reaction

2021 ◽  
Vol 45 (39) ◽  
pp. 18482-18490
Author(s):  
Xiaoqiang Wu ◽  
Chaoyou Yong ◽  
Xuguang An ◽  
Qingquan Kong ◽  
Weitang Yao ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Small Molecule ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Oxidation Reaction ◽  
Cost Effective ◽  
Oxidation Reactions ◽  
Energy Applications ◽  
Highly Active ◽  
Cu Alloy

Ni–Cu alloy-based nanomaterials are representative cost-effective materials that have been widely used as highly active and stable electrocatalysts for electrochemical energy applications, such as the water oxidation reaction, the methanol/ethanol reaction and many other small molecule oxidation reactions.

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