Oxygen evolution reaction (OER) is an essential electrochemical reaction in water-splitting and rechargeable-metal-air-batteries to achieve clean energy production and efficient energy-storage. At ...first, this review discusses about the mechanism for OER, where an oxygen molecule is produced with the involvement of four electrons and OER intermediates but the reaction pathway is influenced by the pH. Then, this review summarizes the brief discussion on theoretical calculations, and those suggest the suitability of NiFe based catalysts for achieving optimal adsorption for OER intermediates by tuning the electronic structure to enhance the OER activity. Later, we review the recent advancement in terms of synthetic methodologies, chemical properties, density functional theory (DFT) calculations, and catalytic performances of several nanostructured NiFe-based OER electrocatalysts, and those include layered double hydroxide (LDH), cation/anion/formamide intercalated LDH, teranary LDH/LTH (LTH: Layered-triple-hydroxide), LDH with defects/vacancies, LDH integrated with carbon, hetero atom doped/core-shell structured/heterostructured LDH, oxide/(oxy)hydroxide, alloy/mineral/boride, phosphide/phosphate, chalcogenide (sulfide and selenide), nitride, graphene/graphite/carbon-nano-tube containing NiFe based electrocatalysts, NiFe based carbonaceous materials, and NiFe-metal-organic-framework (MOF) based electrocatalysts. Finally, this review summarizes the various promising strategies to enhance the OER performance of electrocatalysts, and those include the electrocatalysts to achieve ~1000 mA cm−2 at relatively low overpotential with significantly high stability.
Display omitted
•NiFe based earth-abundant-electrocatalysts for OER in alkaline medium are reviewed.•Strategies used to achieve enhanced OER performance of electrocatalysts are reviewed.•The nanostructured electrocatalysts facilitate the gas evolution.•The electrocatalysts can generate active sites with optimal binding energy.
Electrochemical water-splitting is one of the promising ways for producing clean chemical fuel (Hydrogen) while cheap-earth-abundant-bifunctional-electrocatalyst is one of the possible way for ...improving the overall cost efficiency of water-splitting. This paper reviews the chemical state, hydrogen and oxygen evolution reaction activity in alkaline media, overall water-splitting performance in alkaline media, stability, and possible-factors for improving its efficiency of various kinds of recently reported electrocatalyst such as Ni-P, Co-P, Ni-Co-P, graphene-Co-P, O/N/C-Co/Ni, Ni-S, B-Ni/Co, Ni-Co, Mo, Se, Fe, Mn/Zn/Ti, and metal-free based earth-abundant-bifunctional-electrocatalyst. This paper also reviews and highlights the remarkable water splitting performance of the earth-abundant-bifunctional-electrocatalyst those exhibit better or well comparable with Pt/C//RuO2.
•Water-splitting of earth-abundant-bifunctional-HER-OER-electrocatalysts is reviewed.•The bifunctional-electrocatalysts exhibit better or well-comparable with Pt/C//RuO2.•Earth-abundant-bifunctional-HER-OER-electrocatalysts exhibit significant stability.
Developing earth-abundant-electrocatalysts for oxygen evolution reaction is one of the promising ways to achieve efficient water-splitting for hydrogen production (a clean chemical fuel). This paper ...reviews the activity, stability and durability for oxygen evolution reaction in alkaline medium of different types of recently reported electrocatalysts such as Ni, Co, NiCo, Fe, Se, Mo, Cu, Mn, Zn, V, Ti/Ta, and metal free based earth-abundant-electrocatalysts. Further, this paper reviews the strategies used to achieve the remarkably low overpotential (including η10: ≤100 mV), high long term stability (including ≥100 h) and high durability (including ≥5000 cycles) of earth-abundant-electrocatalysts for oxygen evolution reaction in alkaline medium and those are better or well comparable with the state-of-the-art IrO2 electrocatalyst2. Finally, this paper summarizes the efficient strategies such as preparing porous or nanostructured materials, preparing quantum sized materials, doping metals or heteroatoms, tuning the optimal crystal structure, preparing bimetallic/multi-metallic materials, preparing materials with oxygen vacancies/defects, preparing amorphous materials, preparing metal chalcogenides, preparing metal oxy hydroxides, and integrating electrocatalysts with carbon to enhance the activity, stability, and durability for OER.
Display omitted
•Earth-abundant-electrocatalysts for OER in alkaline medium are reviewed.•The electrocatalysts exhibit remarkably higher activity for OER than IrO2.•The electrocatalysts exhibit remarkably higher stability for OER than IrO2.•The electrocatalysts exhibit remarkably high durability for OER.•Strategies used to achieve high performance of electrocatalysts for OER are reviewed.
Constructing nanoarrays is a promising way to achieve efficient overall water‐splitting for H2 production. At first, this paper introduces the significance of constructing nanoarrays for gas ...evolution reactions: Constructing electrocatalyst with nanoarray structure can provide superaerophobic surface, which can lower the bubble adhesive force and bubble size by forming a discontinuous triple phase contact line (TPCL), and that can facilitate the release of gas, while it can afford abundant active sites, and that can enhance the activity and stability for gas evolution reactions. Then, we review the activity (including ≤1.49 V), and stability (including ≥100 h) for overall water splitting in alkaline medium of various kinds of recently reported earth‐abundant 3D nanoarray bifunctional electrocatalysts. Later, we review the efficient strategies such as constructing nanoarrays with doping metals/heteroatoms, bimetallic/multi‐metallic materials, metal oxides, metal phosphide/phosphate, metal nitrides, carbon, amorphous materials, metal chalcogenides (metal sulfides and selenides), core‐shell/hetero/hollow structure, vacancies/defects, and well‐matched electrode pair to achieve efficient overall water splitting. Then, we review the construction of earth‐abundant nanoarray bifunctional electrocatalyst for efficient overall water splitting in acid medium. Finally, we discussed the gas separation in water electrolysis.
Split review: Constructing nanoarrays is a promising way to achieve efficient overall water‐splitting for H2 production. Constructing electrocatalyst with nanoarray structure can provide superaerophobic surface, which can lower the bubble adhesive force and bubble size. This can facilitate the release of gas, which, in turn, can enhance the activity and the stability for gas evolution reactions. This paper reviews the various efficient strategies used to construct earth‐abundant 3D nanoarray electrocatalysts to achieve efficient overall water splitting.
Several promising strategies used for tuning the electronic structure of the earth-abundant electrocatalysts to achieve enhanced performance for oxygen evolution reaction in alkaline environment have ...been reviewed.
Display omitted
Tuning the electronic structure of the electrocatalysts for oxygen evolution reaction (OER) is a promising way to achieve efficient alkaline water splitting for clean energy production (H2). At first, this paper introduces the significance of the tuning of electronic structure, where modifying the electronic structure of the electrocatalysts could generate active sites having optimal adsorption energy with OER intermediates, and that could diminish the energy barrier for OER, and that could improve the activity for OER. Later, this paper reviews the tuning of electronic structure along with catalytic performances, synthetic methodologies, chemical properties, and DFT calculations on various nanostructured earth-abundant electrocatalysts for OER in alkaline environment. Further, this review discusses the tuning of the electronic structure of the several nanostructured earth-abundant electrocatalysts including oxide, (oxy)hydroxide, layered double hydroxide, alloy, metal phosphide/phosphate, nitride, sulfide, selenide, carbon containing materials, MOF, core–shell/hetero/hollow structured materials, and materials with vacancies/defects for OER in alkaline environment (including activity: overpotential (η) of ≤200 mV at 10 mA cm−2; stability: ≥100 h; durability: ≥5000 cycles). Then, this review discusses the robust stability of the electrocatalysts for OER towards practical application. Moreover, this review discusses the in situ formation of thin layer on the catalyst surface during OER. In addition, this review discusses the influence of the adsorption energy of the OER intermediates on OER performance of the catalysts. Finally, this review summarizes the various promising strategies for tuning the electronic structure of the electrocatalysts to achieve enhanced performance for OER in alkaline environment.
Developing earth-abundant-electrocatalysts for hydrogen evolution reaction is one of the promising ways to achieve efficient water-splitting for hydrogen production (a clean chemical fuel). This ...paper reviews the activity, stability and durability for hydrogen evolution reaction in alkaline medium of different types of recently reported potential electrocatalysts such as Ni, Co, NiCo, Fe, Cu, W, Mo, Se, Mn, Zn, V, and metal free based earth-abundant-electrocatalysts. Further, this paper reviews the strategies used to achieve the remarkably low overpotential (including η10: ≤ 35 mV), high long term stability (including ≥ 100 h) and high durability (including ≥ 5000 cycles) of potential earth-abundant-electrocatalysts for hydrogen evolution reaction in alkaline medium and those are better or well comparable with the state-of-the-art, noble, Pt/C electrocatalyst. Finally, this paper summarizes the efficient strategies such as preparing porous structured materials, preparing nanostructured materials with superaerophobic surface, preparing nanostructured materials, preparing carbon composites/integrating electrocatalysts with carbon, preparing amorphous materials, preparing materials with oxygen vacancies/defects, preparing metal chalcogenides, preparing bimetallic/multi-metallic materials, doping metals or heteroatoms, preparing electrocatalysts with core-shell structure, decorating electrocatalysts with amines, preparing homo-junction/heterojunction structured materials, preparing hollow structured materials, and preparing boron-rich surface to enhance the activity, stability, and durability for HER.
Display omitted The strategies used to achieve the significantly low overpotential, high long term stability and high durability of potential earth-abundant-electrocatalysts for hydrogen evolution reaction in alkaline medium have been reviewed.
Flexible energy storage devices are essential for emerging flexible electronics. The existing state-of-the-art Li-ion batteries are slowly reaching their limitation in terms of cost and energy ...density. Hence, flexible Na-ion batteries (SIBs) with abundance Na resources and Li–S batteries with high energy density become the alternative for the Li-ion batteries in future. This review summarizes the recent advances in the development of flexible electrode materials for SIBs with metallic matrix and carbonaceous matrix such as carbon nano-tubes, carbon nano-fiber, graphene, carbon cloth, carbon fiber cloth, and cotton textiles. Then, the potential prototype flexible full SIBs are discussed. Further, the recent progress in the development of flexible electrode materials for Li–S batteries based on carbon nano-fiber, carbon nano-tubes, graphene, and cotton textiles is reviewed. Moreover, the design strategies of suitable interlayer, separator, electrolyte, and electrodes to prevent the dissolution and shuttle effect of polysulfides in flexible Li–S batteries are provided. Finally some prospective investigation trends towards future research of flexible SIBs and Li–S batteries are also proposed and discussed. The scientific and engineering knowledge gained on flexible SIBs and Li–S batteries provides conceivable development for practical application in near future.
The recent advances in the development of flexible electrode materials with metallic matrix and carbonaceous matrix for flexible Na-ion batteries (with abundance Na resources) and Li–S batteries (with high energy density) have been reviewed. Display omitted
The Na-ion-batteries are considered much attention for the next-generation power-sources due to the high abundance of Na resources that lower the cost and become the alternative for the state of the ...art Li-ion batteries in future. In this review, the recently reported potential cathode and anode candidates for Na-ion-batteries are identified in-light-of-their high-performance for the development of Na-ion-full-cells. Further, the recent-progress on the Na-ion full-cells including the strategies used to improve the high cycling-performance (stable even up-to 50000 cycles), operating voltage (even ≥ 3.7 V), capacity (>350 mAhg−1 even at 1000 mAg−1 (based-on-mass-of-the-anode)), and energy density (even up-to 400 Whkg−1) are reviewed. In addition, Na-ion-batteries with the electrodes containing reduced graphene oxide, and the recent developments on symmetric Na-ion-batteries are discussed. Further, this paper identifies the promising Na-ion-batteries including the strategies used to assemble full-cell using hard-carbon-anodes, Na3V2(PO4)3 cathodes, and other-electrode-materials. Then, comparison between aqueous and non-aqueous Na-ion-batteries in terms of voltage and energy density has been given. Later, various types of electrolytes used for Na-ion-batteries including aqueous, non-aqueous, ionic-liquids and solid-state electrolytes are discussed. Finally, commercial and technological-developments on Na-ion-batteries are provided. The scientific and engineering knowledge gained on Na-ion-batteries afford conceivable development for practical application in near future.
Display omitted
•Recent potential cathode/anode candidates for Na-ion batteries (SIBs) are identified.•Na-ion full-cell with high operating voltage range, and capacity are reviewed.•Na-ion full-cell with high cycling performance, and energy density are discussed.•Promising full-cell with hard carbon, Na3V2(PO4)3, and other electrodes are reviewed.•Comparison between aqueous and non-aqueous SIBs in terms of performance is discussed.
Adsorption of Reactive Black 5 and Congo Red from aqueous solution by coffee waste modified with polyethylenimine was investigated. The removal percentages of both dyes increased with amount of ...polyethyleneimine in the modified adsorbent. Characterization revealed that polyethyleneimine modification improved the adsorbent surface chemistry, while slight improvement of adsorbent textural properties was also observed. The adsorbent's excellent performance was demonstrated by high removal percentages towards the anionic dyes in most experimental runs. The modelling result showed that anionic dyes adsorption occurred via monolayer adsorption, and chemisorption was the rate-controlling step. The adsorbent possesses higher maximum adsorption capacity towards Reactive Black 5 (77.52 mg/g) than Congo Red (34.36 mg/g), due to the higher number of functional groups in Reactive Black 5 that interact with the adsorbent. This study reveals the potential of adsorbent derived from coffee waste in textile wastewater treatment. Furthermore, surface chemistry modification is proven as an effective strategy to enhance the performance of biowaste-derived adsorbents.
•A hybrid weight bat algorithm (WBA) proposed to training deep neural network (DNN).•The proposed WBA-DNN is used for classification of poisonous wild plants.•The proposed WBA-DNN outperformed the ...most well-known classification algorithms.•The poisonous and harmful wild plants in fields could be successfully recognized.
In this study, a deep neural network structure is proposed for the classification of poisonous and harmful wild plants in fields. Furthermore, a novel metaheuristic weight bat-inspired algorithm is developed for training the devised deep neural network. The harmful wild plant dataset is obtained from the agricultural field contains the purslane plants and harmful plants. The feature of the plants extract with mean absolute deviation, the dataset is consists of four features, two classes information, and contains 3452 samples, one-third of these samples are classified as purslane plants. Firstly, the performance of the proposed weight bat-inspired algorithm based deep neural network is evaluated by using ten UCI data repository datasets and the obtained results are compared with state-of-the-art classification algorithms. Then, classification of the harmful wild plant dataset is performed, results of the proposed weight bat-inspired algorithm based deep neural network are compared to two categories of classification algorithms, including (i) the most well-known classification algorithms, including decision tree, k-nearest neighbors, backpropagation based deep neural network, naïve bayes, random forest, AdaBoost, and support vector machine; (ii) optimization-based deep neural network, including bat algorithm, genetic algorithm, particle swarm optimization, equilibrium optimizer, A bio-inspired based optimization algorithm, and salp swarm algorithm. The proposed weight bat-inspired algorithm based deep neural network has outperformed the most well-known classification algorithms and optimization-based deep neural network in terms of CA, FPR, REC, PRE, TNR, AUC, F1-M, and F-M by 0.980, 0.020, 0.980, 0.980, 0.980, 0.980, 0.980, and 0.980, respectively. The highest performance has indicated that the training of deep neural networks by the weight bat-inspired algorithm is proven to be a very effective and useful tool for the classification of poisonous and harmful wild plants.
PDF
