scholarly journals Nano-sized manganese oxides as biomimetic catalysts for water oxidation in artificial photosynthesis: a review

2012 ◽  
Vol 9 (75) ◽  
pp. 2383-2395 ◽  
Author(s):  
Mohammad Mahdi Najafpour ◽  
Fahimeh Rahimi ◽  
Eva-Mari Aro ◽  
Choon-Hwan Lee ◽  
Suleyman I. Allakhverdiev
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Water Oxidation ◽  
Active Sites ◽  
Manganese Oxides ◽  
Metal Compounds ◽  
Functional Models ◽  
Current Densities ◽  
Conversion Efficiencies ◽  
Manganese Compounds

There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese–calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups.

scholarly journals Hydrogen production from water electrolysis: role of catalysts

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Shan Wang ◽  
Aolin Lu ◽  
Chuan-Jian Zhong
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Noble Metal ◽  
Active Sites ◽  
Current Knowledge ◽  
Low Cost ◽  
Critical Role ◽  
Water Electrolysis ◽  
Efficient Production ◽  
Production Of Hydrogen

AbstractAs a promising substitute for fossil fuels, hydrogen has emerged as a clean and renewable energy. A key challenge is the efficient production of hydrogen to meet the commercial-scale demand of hydrogen. Water splitting electrolysis is a promising pathway to achieve the efficient hydrogen production in terms of energy conversion and storage in which catalysis or electrocatalysis plays a critical role. The development of active, stable, and low-cost catalysts or electrocatalysts is an essential prerequisite for achieving the desired electrocatalytic hydrogen production from water splitting for practical use, which constitutes the central focus of this review. It will start with an introduction of the water splitting performance evaluation of various electrocatalysts in terms of activity, stability, and efficiency. This will be followed by outlining current knowledge on the two half-cell reactions, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), in terms of reaction mechanisms in alkaline and acidic media. Recent advances in the design and preparation of nanostructured noble-metal and non-noble metal-based electrocatalysts will be discussed. New strategies and insights in exploring the synergistic structure, morphology, composition, and active sites of the nanostructured electrocatalysts for increasing the electrocatalytic activity and stability in HER and OER will be highlighted. Finally, future challenges and perspectives in the design of active and robust electrocatalysts for HER and OER towards efficient production of hydrogen from water splitting electrolysis will also be outlined.

scholarly journals Synergies of co-doping in ultra-thin hematite photoanodes for solar water oxidation: In and Ti as representative case

RSC Advances ◽  
2020 ◽  
Vol 10 (55) ◽  
pp. 33307-33316
Author(s):  
Aadesh P. Singh ◽  
Camilla Tossi ◽  
Ilkka Tittonen ◽  
Anders Hellman ◽  
Björn Wickman
Keyword(s):  
Thin Film ◽  
Hydrogen Production ◽  
Solar Energy ◽  
Water Splitting ◽  
Water Oxidation ◽  
Representative Case ◽  
Solar Water ◽  
Co Doping ◽  
Pec Cells ◽  
Solar Water Oxidation

Solar energy induced water splitting in photoelectrochemical (PEC) cells is one of the most sustainable ways of hydrogen production. In this work, hematite (α-Fe2O3) thin film were modified by In3+ and Ti4+ co-doping for enhanced PEC performance.

scholarly journals Engineering active sites on hierarchical transition bimetal oxides/sulfides heterostructure array enabling robust overall water splitting

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Panlong Zhai ◽  
Yanxue Zhang ◽  
Yunzhen Wu ◽  
Junfeng Gao ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Active Sites ◽  
Rational Design ◽  
Large Scale ◽  
Grand Challenge ◽  
Long Term Stability ◽  
Large Current ◽  
Electrode Cell ◽  
Large Current Density ◽  
Current Densities

Abstract Rational design of the catalysts is impressive for sustainable energy conversion. However, there is a grand challenge to engineer active sites at the interface. Herein, hierarchical transition bimetal oxides/sulfides heterostructure arrays interacting two-dimensional MoOx/MoS2 nanosheets attached to one-dimensional NiOx/Ni3S2 nanorods were fabricated by oxidation/hydrogenation-induced surface reconfiguration strategy. The NiMoOx/NiMoS heterostructure array exhibits the overpotentials of 38 mV for hydrogen evolution and 186 mV for oxygen evolution at 10 mA cm−2, even surviving at a large current density of 500 mA cm−2 with long-term stability. Due to optimized adsorption energies and accelerated water splitting kinetics by theory calculations, the assembled two-electrode cell delivers the industrially relevant current densities of 500 and 1000 mA cm−2 at record low cell voltages of 1.60 and 1.66 V with excellent durability. This research provides a promising avenue to enhance the electrocatalytic performance of the catalysts by engineering interfacial active sites toward large-scale water splitting.

Hexagonal SiC with spatially separated active sites on polar and nonpolar facets achieving enhanced hydrogen production from photocatalytic water reduction

2018 ◽  
Vol 20 (7) ◽  
pp. 4787-4792 ◽  
Author(s):  
Da Wang ◽  
Ning Liu ◽  
Zhongnan Guo ◽  
Wenjun Wang ◽  
Liwei Guo ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Hydrogen Production ◽  
Water Splitting ◽  
Active Sites ◽  
Spatial Separation ◽  
Water Reduction

The spatial separation of the photo-generated electrons and holes between the polar Si-{0001} and non-polar {10−10} crystal facets on 6H-SiC highly improves the photocatalytic activity of water splitting by nearly 5 times.

In situ Synthesis of Nickel-Dimethylglyoxime/Black Phosphorus Nanorods for Photocatalytic Hydrogen Production from Water Splitting

NANO ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. 2050125
Author(s):  
Hui’e Wang
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Active Sites ◽  
Hydrogen Generation ◽  
Hollow Structure ◽  
Black Phosphorus ◽  
In Situ Growth ◽  
Photocatalytic Hydrogen Production ◽  
Reaction Cycles

Here, a novel material consisting of black phosphorus (BP) and nickel-dimethylglyoxime nanorods was successfully prepared via a facile in situ calcination strategy, which possesses efficient catalytic activity for hydrogen production from water splitting. The reason for this phenomenon was explained by a series of characterization technologies such as SEM, TEM, XRD, UV–Vis, XPS and photoelectrochemical. We demonstrated that the fast e− transport channels were provided by the formed hollow structure of C@Ni-D nanorods, the highly exposed active sites on C@Ni-BP nanorods benefiting from the direct in situ growth of BP, the resulted synergetic effects of C@Ni-D-2 nanorods and BP achieved a better performance of photocatalytic hydrogen production from water splitting. The optimal hydrogen generation of C@Ni-BP-2 nanorods could reach up to 600[Formula: see text][Formula: see text]mol within 180[Formula: see text]min and the rate of hydrogen production did not decrease significantly after four repeated reaction cycles. This work may offer new direction in situ growth of novel catalysts for achieving highly efficient hydrogen production.

Ultrathin NiCo2O4 nanosheets with dual-metal active sites for enhanced solar water splitting of a BiVO4 photoanode

2019 ◽  
Vol 7 (39) ◽  
pp. 22274-22278 ◽  
Author(s):  
Chenchen Feng ◽  
Qi Zhou ◽  
Bin Zheng ◽  
Xiang Cheng ◽  
Yajun Zhang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Active Sites ◽  
Oxygen Vacancies ◽  
Solar Water ◽  
Solar Water Splitting ◽  
Highly Efficient ◽  
Dual Metal ◽  
Nico2o4 Nanosheets ◽  
First Time

Spinel-structured NiCo2O4 nanosheets with dual-metal active sites, an ultrathin structure, and abundant oxygen vacancies were decorated for the first time on a BiVO4 photoanode for highly efficient PEC water oxidation.

scholarly journals Photocatalytic Hydrogen Evolution from Water Splitting Using Core-Shell Structured Cu/ZnS/COF Composites

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3380
Author(s):  
Wenmin Wang ◽  
Bing Li ◽  
Hsin-Ju Yang ◽  
Yuzhi Liu ◽  
Lakshmanan Gurusamy ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Active Sites ◽  
Fossil Fuels ◽  
High Energy ◽  
High Energy Density ◽  
Core Shell ◽  
Porous Network ◽  
Photocatalytic Hydrogen Production ◽  
Redox Sites

Hydrogen is considered to be a very efficient and clean fuel since it is a renewable and non-polluting gas with a high energy density; thus, it has drawn much attention as an alternative fuel, in order to alleviate the issue of global warming caused by the excess use of fossil fuels. In this work, a novel Cu/ZnS/COF composite photocatalyst with a core-shell structure was synthesized for photocatalytic hydrogen production via water splitting. The Cu/ZnS/COF microspheres formed by Cu/ZnS crystal aggregation were covered by a microporous thin-film COF with a porous network structure, where COF was also modified by the dual-effective redox sites of C=O and N=N. The photocatalytic hydrogen production results showed that the hydrogen production rate reached 278.4 µmol g−1 h−1, which may be attributed to its special structure, which has a large number of active sites, a more negative conduction band than the reduction of H+ to H2, and the ability to inhibit the recombination of electron-hole pairs. Finally, a possible mechanism was proposed to effectively explain the improved photocatalytic performance of the photocatalytic system. The present work provides a new concept, in order to construct a highly efficient hydrogen production catalyst and broaden the applications of ZnS-based materials.

scholarly journals Controllable Synthesis of 2D Nonlayered Cr2S3 Nanosheets and Their Electrocatalytic Activity Toward Oxygen Evolution Reaction

2021 ◽  
Vol 3 ◽  
Author(s):  
Tofik Ahmed Shifa ◽  
Raffaello Mazzaro ◽  
Vittorio Morandi ◽  
Alberto Vomiero
Keyword(s):  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Chemical Vapor ◽  
Great Promise ◽  
Fertile Ground ◽  
Earth Abundant ◽  
Controllable Growth ◽  
Current Densities

The design of oxygen evolution reaction (OER) electrocatalysts based on Earth-abundant materials holds great promise for realizing practically viable water-splitting systems. In this regard, two-dimensional (2D) nonlayered materials have received considerable attention in recent years owing to their intrinsic dangling bonds which give rise to the exposure of unsaturated active sites. In this work, we solved the synthesis challenge in the development of a 2D nonlayered Cr2S3 catalyst for OER application via introducing a controllable chemical vapor deposition scheme. The as-obtained catalyst exhibits a very good OER activity requiring overpotentials of only 230 mV and 300 mV to deliver current densities of 10 mA cm−2 and 30 mA cm−2, respectively, with robust stability. This study provides a general approach to optimize the controllable growth of 2D nonlayered material and opens up a fertile ground for studying the various strategies to enhance the water splitting reactions.

scholarly journals Covalent organic frameworks in Lieb lattice for tunable photocatalytic water splitting under visible light

2021 ◽  
Author(s):  
Hongde Yu ◽  
Dong Wang
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Active Sites ◽  
Rational Design ◽  
Near Infrared ◽  
Band Alignment ◽  
Covalent Organic Frameworks ◽  
Photocatalytic Water Splitting ◽  
Metal Free ◽  
Lieb Lattice

Covalent organic frameworks (COFs) with highly designable skeleton and inherent pores have emerged as promising organic photocatalysts for hydrogen production. However, inefficient solar light harvesting, strong excitonic effect, and the lack of active sites still pose major challenges to the rational design of COFs for efficient photocatalytic water splitting and the structure-property relationship has not been established. In this work, we investigated the fundamental mechanism of photoelectrochemical conversion in fully conjugated donor (D)-acceptor (A) COFs in Lieb lattice and proposed a facile strategy to achieve broad visible and near-infrared absorption, prompt exciton dissociation, tunable band alignment for overall water splitting, and metal-free catalysis of hydrogen production. Interestingly, we found that the exciton binding energy was substantially reduced with the narrowing of optical band gap and the increase of static dielectric constant. Further, we unraveled that the hydrogen bond played a vital role in suppressing the overpotential for hydrogen evolution reaction to enable metal-free catalysis. These findings not only highlight a novel route to modulating electronic properties of COFs towards high photocatalytic activity for water splitting, but also offer tremendous opportunities to design metal-free catalysts for other chemical transformations.

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