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European Journal of Applied Sciences – Vol. 12, No. 5
Publication Date: October 25, 2024
DOI:10.14738/aivp.125.17623.
Babaa, S. & Khzouz, M. (2024). Hydrogen Production Methods: A Literature Review. European Journal of Applied Sciences, Vol -
12(5). 188-193.
Services for Science and Education – United Kingdom
Hydrogen Production Methods: A Literature Review
Saleh Babaa
Systems Engineering Department, Military Technological College
(Affiliated with University of Portsmouth, UK), Muscat, Oman
Martin Khzouz
Systems Engineering Department, Military Technological College
(Affiliated with University of Portsmouth, UK), Muscat, Oman
ABSTRACT
Hydrogen is widely recognized as one of the keys ‘players’ in the integration
process of sustainable energy systems. In this paper, the present hydrogen
production techniques are presented based on their working principle, efficiency
and the problems associated with them. These methods comprise Steam Methane
Reforming (SMR), water electrolysis, thermochemical methods of water splitting,
biologically-augurated techniques and advanced methods of water dissolving
including the photoelectrochemical water splitting and the plasma reforming
ones. Analysis of the past and future use of these methods.
Keywords: Overview, Hydrogen, Production, Methods, Comparison.
INTRODUCTION
Currently, the world faces tremendous shifts in the energy mix that are triggered by the
necessity to decarbonize the economy and strengthen energy security. Amongst these,
hydrogen that has high energy density and close to zero emission in fuel cell applications is
expected to be used in this transformation. Nevertheless, the production of hydrogen is a
major issue that factors resourceful, economic, and sustainable techniques.
The paper aims at revealing the current state of the main methods for hydrogen generation,
describing the most significant achievements and their consequences for future energy
production. It is with the purpose of discussing the principles, efficiencies, and environment
concerns of Steam Methane Reforming, water electrolysis, thermochemical water split,
biologically produced hydrogen, and other advanced methods like Photoelectrochemical
Water Splitting and plasma reforming of methane, this paper provides the status and
prospects of hydrogen production systems.
The review also considers the technological aspects of the methods sketched and their
economic perspectives, which might be useful for understanding the current state of the
research carried out to enhance the efficiency of hydrogen production, to reduce its costs, and
to decrease its negative impact upon the environment. In this way, the paper aims at
providing a valuable input to the discursive body of knowledge concerning sustainable energy
sources and the position of hydrogen in the global energy supply chain.
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Babaa, S. & Khzouz, M. (2024). Hydrogen Production Methods: A Literature Review. European Journal of Applied Sciences, Vol - 12(5). 188-193.
URL: http://dx.doi.org/10.14738/aivp.125.17623
LITERATURE REVIEW
Steam Methane Reforming
Steam Methane Reforming (SMR) in current time is the most widely used technique in
hydrogen generation, which controls almost 50 % of the hydrogen market [3]. SMR is the
reaction of methane with steam at high temperatures of 700-1100 °C and pressures and it
forms hydrogen and carbon monoxide while the second process converts the latter to
hydrogen and carbon dioxide. The overall process is represented by the equations: The
overall process is represented by the equations:
CH4 + H2O → CO + 3H2
CO + H2O → CO2 + H2
Although SMR have a high efficiency, they are going to contribute CO2 emissions and the use
of fossil fuels hence it has negative impacts on the environment and sustainability [2].
Electrolysis of Water
Electrolysis is a process in which water is decomposed by the help of electrical energy to
produce hydrogen and oxygen. Also, it has been regarded as one of the techniques with the
highest potential in generating highly pure hydrogen when coupled with renewable energy
sources. The overall reaction for water electrolysis is:
2H2O + 2H2 → O2
The main forms of electrolysis technologies include the Alkaline electrolysis, polymer
electrolyte membrane (PEM) electrolysis, and the Solid oxide electrolysis. Of all these
methods, PEM electrolysis is efficient and responds quickly to voltage variations and hence it
is costly because of the used expensive membrane [3]. Current developments in catalyst
materials and membrane technology are meant to cut down these costs and increase
effectiveness [4].
Thermochemical Water Splitting
Thermochemical water splitting is a method where heat energy commonly sourced from solar
or nuclear heat is used to catalyze chemical reactions that enable hydrogen to be extracted
from water by reduction while oxygen is oxidized. Some of the examples of thermochemical
processes are the sulfur-iodine cycle, and the hybrid sulfur cycle. These cycles can come closer
to achieve high efficiencies and can be integrated with renewable energy sources but the
requirement of high temperature reactors, and strong materials to oppose the severe
environments [5].
Biological Methods
The methods used in biological production of hydrogen include bio-photolysis, photo- Fermentation as well as dark fermentation carried out by microorganisms. These techniques
are still in the research stage for the most part, yet they represent the future of renewable
hydrogen from organic waste, with the sunlight’s capability. Bio-photolysis occurs using algae
which scission water under sunlight, photo fermentation and dark fermentation by using
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European Journal of Applied Sciences (EJAS) Vol. 12, Issue 5, October-2024
bacteria in conversion of organic substances to hydrogen [6]. Genetic engineering and
optimization of the metabolisms are vital for the enhancement of scale and effectiveness of
the biological approaches [7].
Advanced Methods
Some of the newly developed hydrogen production technologies include
photoelectrochemical water splitting and plasma reforming. Unlike some other systems,
photoelectrochemical water splitting works by utilizing semiconductors to generate
chemicals and in this case, hydrogen using solar energy. This method involves a direct and
potentially cheap way of producing semiconductors for the enhancement of the photocatalytic
efficiency and stability of the semiconductor materials [8]. Plasma reforming on the other
hand uses plasma to initiate chemical reactions at a lower temperature as in the conventional
thermal processes which can also cut down energy consumption and emission levels [9].
DISCUSSION AND ANALYSIS
Efficiency and Environmental Impact
The four methods of hydrogen generation are seen to offer variable efficacies and effects on
the surroundings. Thus, although SMR is significantly more efficient than other methods, it
also produces extensive amounts of CO2 that offset its positive impacts on the environment.
Techniques such as Carbon capture and storage are being applied to reduce these emissions;
however, this makes the process more expensive and more complicated [10].
Electrolysis, especially polymer electrolyte membrane electrolysis, has qualities of producing
high purity hydrogen and can be acknowledged to be powered with renewable energy hence
has a zero-emission index. However, they have the following disadvantages: high costs of
working on present-day electrolyzes and the unsteady supply of renewable energy resources.
There is a need to further develop renewable energy storage to store energy obtained through
renewable sources and another need for reduction of the costs of electrolyzes used in this
method [11].
Among the thermochemical water splitting processes, advanced processes such as the sulfur- iodine cycle, and hybrid sulfur cycle have the potentiality of providing relatively high
efficiency if integrated with high temperature renewable heat sources like concentrated solar
power. Therefore, high-temperature operation and utilization of complex materials which are
essential for Polyphthalamide (PPA) company which can be technical barriers to be taken into
consideration [12].
Biological processes are among the green approaches to hydrogen generation particularly
when the feedstock is organic waste. These methods are not efficient to some extent due to
the slow rates of biological processes and requirement of big bioreactors [13].
Other complex procedures like photoelectrochemical water splitting and plasma reforming
are still among the most researched methods to generate hydrogen. The above methods have
a possible advantage in lower energy usage and the immediate harnessing of solar energy. But
unfortunately, they are very sensitive to efficiency and stability, the necessary jumps of which
can be reached only by utilizing brand-new technologies of materials science [14].