A Critical Review of Renewable Hydrogen Production Methods: Factors Affecting Their Scale-Up and Its Role in Future Energy Generation

Agyekum, Ephraim Bonah; Nutakor, Christabel; Agwa, Ahmed M.; Kamel, Salah

doi:10.3390/membranes12020173

Cited by 190 publications

(56 citation statements)

References 124 publications

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“…In addition, the combustion of hydrogen releases only water as a by-product, and is, therefore, eco-friendly [ 1 , 2 , 3 , 4 ]. Among the several hydrogen production techniques, the electrochemical water-splitting process is the emission-free green route for generating hydrogen with high purity [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. Unfortunately, the efficiency of hydrogen production is severely hindered due to the sluggish oxygen evolution reaction process (OER) at the anode [ 15 , 16 , 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Bimetallic Cu/Fe MOF-Based Nanosheet Film via Binder-Free Drop-Casting Route: A Highly Efficient Urea-Electrolysis Catalyst

et al. 2022

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Developing efficient electrocatalysts for urea oxidation reaction (UOR) can be a promising alternative strategy to substitute the sluggish oxygen evolution reaction (OER), thereby producing hydrogen at a lower cell-voltage. Herein, we synthesized a binder-free thin film of ultrathin sheets of bimetallic Cu-Fe-based metal–organic frameworks (Cu/Fe-MOFs) on a nickel foam via a drop-casting route. In addition to the scalable route, the drop-casted film-electrode demonstrates the lower UOR potentials of 1.59, 1.58, 1.54, 1.51, 1.43 and 1.37 V vs. RHE to achieve the current densities of 2500, 2000, 1000, 500, 100 and 10 mA cm−2, respectively. These UOR potentials are relatively lower than that acquired by the pristine Fe-MOF-based film-electrode synthesized via a similar route. For example, at 1.59 V vs. RHE, the Cu/Fe-MOF electrode exhibits a remarkably ultra-high anodic current density of 2500 mA cm—2, while the pristine Fe-MOF electrode exhibits only 949.10 mA cm−2. It is worth noting that the Cu/Fe-MOF electrode at this potential exhibits an OER current density of only 725 mA cm—2, which is far inconsequential as compared to the UOR current densities, implying the profound impact of the bimetallic cores of the MOFs on catalyzing UOR. In addition, the Cu/Fe-MOF electrode also exhibits a long-term electrochemical robustness during UOR.

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Section: Introductionmentioning

confidence: 99%

Bimetallic Cu/Fe MOF-Based Nanosheet Film via Binder-Free Drop-Casting Route: A Highly Efficient Urea-Electrolysis Catalyst

et al. 2022

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“…This offers a promising circular economics approach for sustainable hydrogen production, as well as responsible waste management [ 2 ]. Another biological process also currently being investigated is bio-photolysis using microalgae (cyanobacteria and green/blue-green algae)—a process in which the microorganisms are used to photosynthetically split water molecules into hydrogen and oxygen [ 3 ].…”

Section: Introductionmentioning

confidence: 99%

“…Dark fermentation has been widely investigated and proven to be the most suitable method for sustainable biohydrogen production [ 3 , 4 ]. Dark fermentation is the process in which suitable microorganisms are used to generate hydrogen gas from suitable carbon substrates under anaerobic conditions and in the absence of a light source [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

A Thermosiphon Photobioreactor for Photofermentative Hydrogen Production by Rhodopseudomonas palustris

2022

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A thermosiphon photobioreactor (TPBR) can potentially be used for biohydrogen production, circumventing the requirement for external mixing energy inputs. In this study, a TPBR is evaluated for photofermentative hydrogen production by Rhodopseudomonas palustris (R. palustris). Experiments were conducted in a TPBR, and response surface methodology (RSM), varying biomass concentration, and light intensity and temperature were employed to determine the operating conditions for the enhancement of both hydrogen production as well as biomass suspension. Biomass concentration was found to have had the most pronounced effect on both hydrogen production as well as biomass suspension. RSM models predicted maximum specific hydrogen production rates of 0.17 mol m−3h−1 and 0.21 mmol gCDW−1h−1 at R. palustris concentrations of 1.21 and 0.4 g L−1, respectively. The experimentally measured hydrogen yield was in the range of 45 to 77% (±3.8%), and the glycerol consumption was 8 to 19% (±0.48). At a biomass concentration of 0.40 g L−1, the highest percentage of biomass (72.3%), was predicted to remain in suspension in the TPBR. Collectively, the proposed novel photobioreactor was shown to produce hydrogen as well as passively circulate biomass.

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“…Figure 6 depicts a Nyquist plot of the impedance measured using an H-type cell. The impedance consisted of a real part and an imaginary part, and it can be expressed as Equation (2). Equation ( 2) suggests that the impedance of the imaginary part was affected by the frequency.…”

Section: The Two-probe Cell Methodsmentioning

confidence: 99%

“…Water electrolysis, which is a representative method among the methods for producing hydrogen, is classified by the electrolyte, which is a passageway for ions. Among them, alkaline water electrolysis (AWE) refers to an electrochemical process to directly convert water under alkaline conditions into hydrogen and oxygen gas through redox reactions occurring when electricity is applied [1,2]. Unlike PEM water electrolysis, AWE has the advantage that it does not require a noble metal catalyst such as platinum, and it does not use an MEA type electrolyte membrane, which is advantageous for a large area.…”

Section: Introductionmentioning

confidence: 99%

Importance of Hydroxide Ion Conductivity Measurement for Alkaline Water Electrolysis Membranes

Lim

Jian

Chun³

et al. 2022

Membranes

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Alkaline water electrolysis (AWE) refers to a representative water electrolysis technology that applies electricity to synthesize hydrogen gas without the production of carbon dioxide. The ideal polymer electrolyte membranes for AWE should be capable of transporting hydroxide ions (OH−) quickly in harsh alkaline environments at increased temperatures. However, there has not yet been any desirable impedance measurement method for estimating hydroxide ions’ conduction behavior across the membranes, since their impedance spectra are significantly affected by connection modes between electrodes and membranes in the test cells and the impedance evaluation environments. Accordingly, the measurement method suitable for obtaining precise hydroxide ion conductivity values through the membranes should be determined. For this purpose, Zirfon®, a state-of-the-art AWE membrane, was adopted as the standard membrane sample to perform the impedance measurement. The impedance spectra were acquired using homemade test cells with different electrode configurations in alkaline environments, and the corresponding hydroxide ion conductivity values were determined based on the electrochemical spectra. Furthermore, a modified four-probe method was found as an optimal measurement method by comparing the conductivity obtained under alkaline conditions.

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A Critical Review of Renewable Hydrogen Production Methods: Factors Affecting Their Scale-Up and Its Role in Future Energy Generation

Cited by 190 publications

References 124 publications

Bimetallic Cu/Fe MOF-Based Nanosheet Film via Binder-Free Drop-Casting Route: A Highly Efficient Urea-Electrolysis Catalyst

Bimetallic Cu/Fe MOF-Based Nanosheet Film via Binder-Free Drop-Casting Route: A Highly Efficient Urea-Electrolysis Catalyst

A Thermosiphon Photobioreactor for Photofermentative Hydrogen Production by Rhodopseudomonas palustris

Importance of Hydroxide Ion Conductivity Measurement for Alkaline Water Electrolysis Membranes

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