scholarly journals Understanding Surface Modulation to Improve the Photo/Electrocatalysts for Water Oxidation/Reduction

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1965
Author(s):  
Yunhee Cho ◽  
Thi Anh Le ◽  
Hyoyoung Lee
Keyword(s):  
Charge Transfer ◽  
Hydrogen Production ◽  
Future Development ◽  
Water Oxidation ◽  
Catalytic Efficiency ◽  
Clean Energy ◽  
Rational Surface ◽  
Electrochemical Process ◽  
Chemical Structures ◽  
Surface Modulation

Water oxidation and reduction reactions play vital roles in highly efficient hydrogen production conducted by an electrolyzer, in which the enhanced efficiency of the system is apparently accompanied by the development of active electrocatalysts. Solar energy, a sustainable and clean energy source, can supply the kinetic energy to increase the rates of catalytic reactions. In this regard, understanding of the underlying fundamental mechanisms of the photo/electrochemical process is critical for future development. Combining light-absorbing materials with catalysts has become essential to maximizing the efficiency of hydrogen production. To fabricate an efficient absorber-catalysts system, it is imperative to fully understand the vital role of surface/interface modulation for enhanced charge transfer/separation and catalytic activity for a specific reaction. The electronic and chemical structures at the interface are directly correlated to charge carrier movements and subsequent chemical adsorption and reaction of the reactants. Therefore, rational surface modulation can indeed enhance the catalytic efficiency by preventing charge recombination and prompting transfer, increasing the reactant concentration, and ultimately boosting the catalytic reaction. Herein, the authors review recent progress on the surface modification of nanomaterials as photo/electrochemical catalysts for water reduction and oxidation, considering two successive photogenerated charge transfer/separation and catalytic chemical reactions. It is expected that this review paper will be helpful for the future development of photo/electrocatalysts.

Boosted charge transfer in oxygen vacancy-rich K+ birnessite MnO2 for water oxidation and zinc-ion batteries

2021 ◽  
Vol 378 ◽  
pp. 138147
Author(s):  
MengXian Lin ◽  
Fuqiang Shao ◽  
Shuting Weng ◽  
Shanshan Xiong ◽  
Shuai Liu ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Oxygen Vacancy ◽  
Water Oxidation ◽  
Zinc Ion

scholarly journals Adsorption for efficient low carbon hydrogen production: part 2—Cyclic experiments and model predictions

Adsorption ◽  
2021 ◽  
Author(s):  
Anne Streb ◽  
Marco Mazzotti
Keyword(s):  
Hydrogen Production ◽  
Carbon Capture And Storage ◽  
Clean Energy ◽  
Separation Performance ◽  
Low Carbon ◽  
Solution Theory ◽  
Feed Composition ◽  
Ideal Adsorbed Solution Theory ◽  
Adsorbed Solution ◽  
Adsorbed Solution Theory

Abstract Hydrogen as clean energy carrier is expected to play a key role in future low-carbon energy systems. In this paper, we demonstrate a new technology for coupling fossil-fuel based hydrogen production with carbon capture and storage (CCS): the integration of CO2 capture and H2 purification in a single vacuum pressure swing adsorption (VPSA) cycle. An eight step VPSA cycle is tested in a two-column lab-pilot for a ternary CO2–H2–CH4 stream representative of shifted steam methane reformer (SMR) syngas, while using commercial zeolite 13X as adsorbent. The cycle can co-purify CO2 and H2, thus reaching H2 purities up to 99.96%, CO2 purities up to 98.9%, CO2 recoveries up to 94.3% and H2 recoveries up to 81%. The key decision variables for adjusting the separation performance to reach the required targets are the heavy purge (HP) duration, the feed duration, the evacuation pressure and the flow rate of the light purge (LP). In contrast to that, the separation performance is rather insensitive towards small changes in feed composition and in HP inlet composition. Comparing the experimental results with simulation results shows that the model for describing multi-component adsorption is critical in determining the predictive capabilities of the column model. Here, the real adsorbed solution theory (RAST) is necessary to describe all experiments well, whereas neither extended isotherms nor the ideal adsorbed solution theory (IAST) can reproduce all effects observed experimentally.

Bifunctional single-atomic Mn sites for energy-efficient hydrogen production

Nanoscale ◽  
2021 ◽  
Author(s):  
Xianyun Peng ◽  
Junrong Hou ◽  
Yuying Mi ◽  
Jiaqiang Sun ◽  
Gaocan Qi ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Energy Saving ◽  
Hydrogen Evolution Reaction ◽  
Energy Efficient ◽  
Low Cost ◽  
Clean Energy ◽  
H2 Production ◽  
Energy Technology ◽  
Highly Active ◽  
Clean Energy Technology

Electrocatalytic hydrogen evolution reaction (HER) for H2 production is essential for future renewable and clean energy technology. Screening energy-saving, low-cost, and highly active catalysts efficiently, however, is still a grand...

Fast microwave-assisted preparation of nickel–copper–chromium-layered double hydroxide as an excellent electrocatalyst for water oxidation

2021 ◽  
Author(s):  
Kamellia Nejati ◽  
Leila Jafari Foruzin ◽  
Zolfaghar Rezvani
Keyword(s):  
Charge Transfer ◽  
Layered Double Hydroxide ◽  
Water Oxidation ◽  
Bandgap Energy ◽  
Microwave Method ◽  
Optimal Amount ◽  
Microwave Assisted ◽  
Nickel Copper ◽  
Copper Chromium ◽  
Double Hydroxide

A well-designed NiCuCr-LDH was prepared using a simple microwave method. According to the OER results, doping optimal amount of Cu2+ into NiCr-LDH displayed superior OER activity, due to decreased bandgap energy and improved charge transfer.

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.

A facile method for regulating the charge transfer route of WO3/CdS in high-efficiency hydrogen production

2019 ◽  
Vol 244 ◽  
pp. 529-535 ◽  
Author(s):  
Lulu Zhang ◽  
Hongwen Zhang ◽  
Bo Wang ◽  
Xueyan Huang ◽  
Yun Ye ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Hydrogen Production ◽  
High Efficiency

scholarly journals Producción de Hidrógeno mediante digestión anaerobia de residuos de planta de jitomate

2019 ◽  
pp. 1-12
Author(s):  
Sarai Camarena-Martínez ◽  
Juan Humberto Martínez-Martínez ◽  
Adriana Saldaña-Robles ◽  
Graciela M.L Ruiz-Aguilar
Keyword(s):  
Hydrogen Production ◽  
Tomato Plant ◽  
Biological Process ◽  
Clean Energy ◽  
High Energy ◽  
Anaerobic Sludge ◽  
Plant Residues ◽  
Lignocellulosic Waste ◽  
Initial Ph ◽  
Native Microflora

Hydrogen (H2) is recognized as a promising energy carrier among the alternatives for obtaining clean energy, since it has a high energy efficiency (122 kJ / g) and can be obtained from lignocellulosic waste through a biological process. In the state of Guanajuato, high amounts of plant waste derived from tomato cultivation are generated because this is the crop mostly produced through protected agriculture. So, the objective of the present study was to consider tomato plant residues for the generation of hydrogen through the anaerobic digestion process. Two sources of inoculum, native microflora of the tomato plant and anaerobic sludge pretreated at 100 ° C for 24 h; and four mineral media at an initial pH of 6.5 ± 0.2 in batch experiments, were evaluated. The highest yield was 37.4 mLH2 / g SV using native microflora and mineral media with yeast extract. Hydrogen production was found like those reported in the literature for other type of waste, highlighting the no-need to pretreat the substrate or inoculum. Therefore, the methodology propose is efficient to the hydrogen production from tomato plant residues.

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