Hydrogen Production Capability Research Articles

ZnIn2S4 nanostructure grown on electronegative h-BN for highly efficient photocatalytic hydrogen evolution

The photo-corrosion issue inherent in metal sulfide semiconductors is quite pronounced, making the enhancement of electron-hole pair separation efficiency in these photocatalysts a pivotal strategy for boosting photocatalytic hydrogen production. This study introduces a novel approach where hexagonal boron nitride (h-BN) acts as a substrate for the in situ growth of ZnIn2S4 nanostructures, resulting in the formation of h-BN@ZnIn2S4 (BN@ZIS) nanocomposites. The electronegativity of h-BN nanosheets is harnessed to facilitate the recombination or electrostatic attraction of photogenerated holes in the ZnIn2S4 photocatalyst. This strategy effectively promotes the separation of photogenerated electron-hole pairs, which is crucial for enhancing photocatalytic performance. The microstructure, morphology and optical properties of BN@ZIS nanocomposites were meticulously investigated. The findings reveal that the incorporation of h-BN nanosheets loads to a more uniform dispersion of the ZnIn2S4 nanostructure, which not only increases the specific surface area but also fosters a tight heterojunction interface between h-BN and ZnIn2S4. In conclusion, the photocatalytic hydrogen production capabilities of the BN@ZIS nanocomposites were rigorously evaluated. Pure h-BN lacks photocatalytic hydrogen production activity. Conversely, the optimized BN@ZIS composite demonstrated a remarkable enhancement, exhibiting a photocatalytic efficiency that is 9.65 times greater than that of pristine ZnIn2S4. Furthermore, a plausible mechanism by which BN@ZIS augments photocatalytic hydrogen production has been proposed. This strategy, leveraging the synergistic interaction between h-BN and ZnIn2S4, is anticipated to be applicable to other semiconductor systems, opening avenues for the advancement of photocatalytic technologies.

Activated Migration of Hydroxide Ion in Anolyte for Enhancing Performance of Scaled-up Non-Noble Catalysts in Pure Water-Fed Anion Exchange Membrane Water Electrolysis

The continuous advancement in water electrolysis technologies has illuminated the potential of sustainable energy sources, particularly in the realm of green hydrogen production. Anion exchange membrane water electrolysis (AEMWE) stands out as a promising technology capable of theoretically yielding high-purity hydrogen. However, the commercialization of AEMWE faces challenges arising from the inherent discord between high performance and the elevated costs associated with noble metal catalysts, such as platinum and iridium. Moreover, prevalent studies often focus on a limited electrode area of less than 4 cm2, thereby restricting the exploitation of the high purity hydrogen production capabilities inherent in AEMWE. This research prioritizes the enhancement of performance through a meticulously crafted membrane-electrode assembly (MEA) employing a 25 cm2 Ni-frame caged NiMoO4 catalyst for cathode synthesis. The observed performance improvement is attributed to the augmented active site of the catalyst, consisting of NiMoO4 entrapped in the Ni substrate during the compression process of the electrode. Additionally, the increase in local pH at the interfacial between electrode and bulk electrolyte is facilitated by the capillary phenomenon resulting from the space between the Ni substrate and the NiMoO4 catalyst layer, leading to enhanced migration of the electrolyte containing hydroxide ions. Acknowledgements This research was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resources from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20213030040590).

Innovative biomass waste heat utilization for green hydrogen production: A comparative and optimization study of steam and organic rankine cycles

Today, designing a green hydrogen production process under an optimal, efficient, and economical configuration is one of the priorities of energy systems engineers. This research aims to explore the application of electricity produced by the steam Rankine cycle (S/RC) and Organic Rankine cycle (ORC) through biomass-based waste heat utilization in an alkaline electrolyzer (AE) system for the production of green hydrogen. The S/RC unit utilizes high-temperature waste heat, while the ORC system utilizes medium to low-temperature ones from the S/RC to improve overall system efficiency and hydrogen output. The study developed eight distinct configurations of the combined system, employing two organic fluids across four ORC designs. It aimed to assess the influence of integrating a recuperator or/and an OFOH (open feed organic heater), as well as varying the organic fluids, on the ORC unit's hydrogen production capability. A detailed thermodynamic, thermo-economic, and eco-economic analysis was conducted to assess key metrics. The environmental analysis quantified the carbon dioxide (CO2) emission reductions achieved through hydrogen production, using the emission rate from the steam methane reforming method as a benchmark. This approach underscored the environmental benefits of the AE system for hydrogen production. Further, the study quantified the financial gains from CO2 reduction, referred to as carbon credit gain (CCG), through an eco-economic analysis. From the outcomes, the highest hydrogen yield and the lowest LCOH (levelized cost of hydrogen) value were 94.65 tons/year and 1.724 US$/kg, respectively, related to Case (IV)-a (biomass waste heat-based S/RC- Regenerative& recuperator ORC system-AE system under R245fa). Lastly, optimization process for maximizing hydrogen production via the optimization methodology was established.

Synergistic effect of NiO-loaded gold NPs modified exfoliated graphitic carbon nitride (E-gC3N4) with the role of hot electrons and hole scavengers for boosting solar hydrogen production

The photocatalytic hydrogen production capabilities of a well-designed NiO–Au loaded exfoliated graphitic carbon nitride (E-gC3N4) were evaluated after it was synthesized in a straightforward, template-free, single-step process. This study delves into the synergistic impact of utilizing exfoliated g-C3N4 (E-gC3N4) loaded with NiO to trap electrons and plasmonic Au to elevate solar-driven H2 evolution through the surface plasmon resonance effect. Using 2 % NiO/E-gC3N4 and 0.3 % Au/E-gC3N4 samples, the H2 yield of 2620 and 2725 μmol g−1, were obtained, which were 25 and 26 folds higher than using bulk g-C3N4, respectively. The highest photocatalytic H2 production of 4750 μmol g−1 was obtained with 1 % NiO-0.3 % Au/E-gC3N4, which was 1.74, 1.81 and 45.24-fold more than it was produced with 0.3 % Au/E-gC3N4, 2 % NiO/E-gC3N4 and bulk g-C3N4 samples, respectively. Increased visible light absorption and charge production due to the SPR effect of Au and efficient charge separation due to NiO co-catalyst led to an increase in H2 generation. The composite was also stable for the consecutive four cycles, in which continuous H2 evolution was obtained. This novel strategy offers promise for synthesizing effective composites for visible-light-driven H2 evolution.

Energetic/economic/scalability assessment of active solar energy and waste heat utilization in urban environments for H2/freshwater production: A CSP-centered multigeneration system with dual-loop power generation

The imperative to reduce greenhouse gas emissions has intensified the need for sustainable thermal energy systems. This study addresses this exigency by harnessing solar energy and exploiting waste heat to augment energy efficiency in urban settings. The proposed system integrates a concentrated solar power-based Brayton cycle with dual power generation, water desalination, and hydrogen production capabilities. Comprehensive technical and economic evaluations affirm the feasibility of this system. Additionally, transient codes have been utilized to ascertain the performance of the proposed configuration. The investigation reveals that the tower and receiver are the primary sites of exergy destruction, accounting for 48.1 % of the total, with the heliostat field, reverse osmosis, and proton exchange membrane electrolysis contributing 24 %, 8.8 %, and 6.9 %, respectively. The findings show that increasing the pressure ratio in the Brayton cycle leads to improved exergy efficiency and increased power output, but also leads to higher overall costs. A thorough economic evaluation shows that the solar unit, which includes the receiver, heliostat field, compressor, and gas turbine, is the main factor influencing costs, representing 62.6 % of the total system cost rate. The dynamic study conducted to forecast the annual system capacity in San Francisco indicates that electricity production peaks during summer at 242.15 MWh. Conversely, winter exhibits the lowest contribution at 17.3 % with 143.11 MWh.

Interplanar spacing and nanosheet thickness regulation of carbon nitride and its “cold” catalytic hydrogen production performance under 10 W LED irradiation

Investigation of hydrogen production catalysis under low-temperature and low-power light irradiation, such as LEDs, is important for energy conservation in cold natural conditions. Interlayer charge transfer in g-C3N4 nanosheets is influenced by the crystal face spacing and nanosheet thickness, due to rapid photogenerated carrier recombination and slow charge transfer, thus enhancing hydrogen production capabilities. Few studies have controlled both crystal face spacing and nanosheet thickness simultaneously. In this research, copper-phosphorus co-doped g-C3N4 was synthesized through one-step thermal polymerization, achieving both control over nanosheet thickness and crystal surface spacing. The hydrogen production rate of 0.5 %Cu/1 %P doped g-C3N4 was increased by 5.25 times and reached 958.98 μmol/g/h under 10 °C and 10 W LED illumination. Copper and phosphorus doping that reduced (002) surface spacing of g-C3N4, resulting in thinner nanosheets. This structural modification facilitated interlayer charge transfer and suppressed photogenerated carrier recombination. This research provides a novel insight and strategy for designing hydrogen production photocatalyst at low temperatures and with low energy consumption.

ZnO/TiO2 heterojunction nanorod array for efficient photoelectrochemical water splitting

This study presents a novel approach utilizing a simple, stable, reproducible CV (Cyclic Voltammetry) electrodeposition method to deposit varying amounts of ZnO onto ordered TiO2 (Rutile) nanorod arrays. Comprehensive investigations were conducted on the morphology, semiconductor band-gap structure of different ZnO/Rutile composites, and their performance in photocatalytic (PC) and photoelectrochemical (PEC) hydrogen production. Results demonstrate that the ZnO/TiO2 photoanodes fabricated in this manner exhibit outstanding PC/PEC hydrogen production capabilities. Particularly noteworthy is the Z/R-15 photoanode, showcasing superior PEC performance with a photocurrent density 3.5 times higher than that of the pristine TiO2 photoanode under equivalent conditions. Furthermore, it was observed that depositing ZnO onto highly crystalline, annealed TiO2 nanorods yields optimal photoelectrical properties. Incorporating oxygen-rich vacancies in ZnO significantly enhances the photoelectrocatalytic performance of TiO2 photoanodes. The CV electrodeposition method offers valuable insights for developing efficient photocatalytic hydrogen production catalysts.

Hydrogen generation by hydrolysis of alkaline NaBH4 solution doped with amorphous catalyst Co–Y2O3–B/CNTs

This investigation enhances the catalytic efficiency of Co–B/CNTs for hydrogen production via sodium borohydride hydrolysis by doping with 5%Y2O3. Such doping significantly boosts hydrogen evolution rates, with Co–Y2O3–B/CNTs achieving a production rate of 1083.43 ml g−1·min−1—surpassing Co–B/CNTs by 1.5 times and tripling that of Co–B catalysts. SEM and XRD analyses show Y2O3 doping reduces particle aggregation and maintains the catalyst's amorphous state, thereby increasing the active surface area. Furthermore, XPS analysis demonstrates that introducing yttrium into Co–B/CNTs catalysts improves their surface elemental composition and valence states. This improvement boosts catalyst performance and stability by enhancing electron transfer and particle size optimization. Optimal hydrolysis is achieved at an NaOH concentration of 2.5 mol/L, with higher concentrations diminishing hydrogen production due to increased viscosity from by-product formation. Additionally, Co–Y2O3–B/CNTs catalysts exhibit commendable durability, maintaining more than two-thirds of their initial activity after five reuse cycles, outperforming comparable catalysts to a moderate extent. These findings underscore the beneficial role of Y2O3 in the Co–B/CNTs framework, promoting Y2O3-doped catalysts for their enhanced efficiency, sustainability, and hydrogen production capabilities.

Levelized cost of hydrogen production in Northern Africa and Europe in 2050: A Monte Carlo simulation for Germany, Norway, Spain, Algeria, Morocco, and Egypt

The production of green hydrogen through electrolysis, utilizing renewable energies, is recognized as a pivotal element in the pursuit of decarbonization. In order to attain cost competitiveness for green hydrogen, reasonable generation costs are imperative. To identify cost-effective import partners for Germany, given its limited green hydrogen production capabilities, this study undertakes an exhaustive techno-economic analysis to determine the potential Levelized Cost of Hydrogen in Germany, Norway, Spain, Algeria, Morocco, and Egypt for the year 2050, which represents a critical milestone in European decarbonization efforts. Employing a stochastic approach with Monte Carlo simulations, the paper marks a significant contribution for projecting future cost ranges, acknowledging the multitude of uncertainties inherent in related cost parameters and emphasizing the importance of randomness in these assessments. Country-specific Weighted Average Cost of Capital are calculated in order to create a refined understanding of political and economic influences on cost formation, rather than using a uniform value across all investigated nations. Key findings reveal that among the evaluated nations, PV-based hydrogen emerges as the most cost-efficient alternative in all countries except Norway, with Spain presenting the lowest Levelized Cost of Hydrogen at 1.66 €/kg to 3.12 €/kg, followed by Algeria (1.72 €/kg to 3.23 €/kg) and Morocco (1.73 €/kg to 3.28 €/kg). Consequently, for economically favorable import options, Germany is advised to prioritize PV-based hydrogen imports from these countries. Additionally, hydrogen derived from onshore wind in Norway (2.24 €/kg to 3.73 €/kg) offers a feasible import alternative. To ensure supply chain diversity and reduce dependency on a single source, a mixed import strategy is advisable. Despite having the lowest electricity cost, Egypt shows the highest Levelized Cost of Hydrogen, primarily due to a significant Weighted Average Cost of Capital.

A comprehensive 3D modelling exploration of a protonic ceramic electrolysis cell stack with metal foam

Protonic ceramic electrolysis cells (PCECs) offer significant potential for large-scale green hydrogen production. The performance of conventional PCEC stacks is notably limited due to the uneven gas distribution. In this research, a new stack design using metal foam as the gas distributor is proposed and numerically evaluated using a 3D Multiphysics model to improve the gas distribution uniformity. At 1.3 V and 600 °C, the current density of the newly designed PCEC with metal foam is 173 % higher than that of the conventional PCEC. Moreover, the hydrogen production capability of metal foam based PCEC is 234 % higher than that of conventional PCEC, due to the improved gas distribution uniformity and faradaic efficiency (FE) of the new PCEC. The application of metal foam increases steam distribution uniformity by 91.2 %. In a conventional PCEC, the FE under the rib is notably lower than that under the channel. In contrast, the FE distribution is more uniform in a metal foam based PCEC. The improved performance in terms of current density, FE, and distribution uniformity highlights the potential of metal foam as a beneficial component in PCEC stacks. These findings contribute to the understanding and further development of PCEC technology.

Enhancing hydrogen production capability from urine-containing sewage through optimization of urea oxidation pathways

The electrochemical urea oxidation reaction (UOR) represents a promising route to sustainable hydrogen production and reuse of urea-containing sewage. However, the efficiency of UOR is hindered by the dehydrogenation of intermediate *CONH2NH and the conversion of toxic intermediate the *CO. Herein, we report a robust strategy to elevate UOR performance by introducing iron (Fe) atoms into the Ni3S2@NiSe2 heterojunctions (denoted Fe-Ni3S2@NiSe2). The Fe-Ni3S2@NiSe2 exhibits remarkable selectivity and electrocatalytic activity towards UOR, attributed to its reconstruction into Fe-NiOOH species during UOR process, as confirmed by in-situ Raman technology. Utilizing Fe-Ni3S2@NiSe2 as both the cathode and anode in a single-chamber electrolytic cell, the hydrogen production rate reaches 588.4 μmol h−1 in simulated urea-containing sewage and 432.1 μmol h−1 in actual human urine, respectively. Notably, in both scenarios, no oxygen product is detected, and the hydrogen production efficiency surpasses that of traditional water splitting by 5.8-fold and 4.3-fold, respectively. In-situ infrared spectroscopy study reveals that the UOR process involves the cleavage of C-N bond and the generation of CO2. Density functional theory calculations further signifies that the incorporation of Fe facilitates the dehydrogenation of *CONH2NH intermediates, strengthens the d-p hybridization, and weakens O-H bonds, thereby resulting in reduced energy barriers for UOR. Our strategy holds promise for efficient hydrogen production from sewage via UOR, offering potential implications for wastewater treatment and clean energy generation.

BiOCl modified TiO2 based catalyst with enhanced hydrogen generation properties under visible light via promote photogenerated electron-hole separation

Due to its wide band gap and low photogenerated carrier separation efficiency, TiO2 has an undesirable photocatalytic activity. In the present work, BiOCl was hydrothermally deposited on TiO2 and BiOCl/TiO2 composites with different ratios were obtained. The results show that 30 % BiOCl/TiO2 has the best performance of 1354.94 μmolg−1h−1, which is 18.4 times than pure TiO2 and 73.1 times than pure BiOCl. The significant increase in the photocatalytic efficiency of BiOCl/TiO2 composites is attributed to the reduction of their bandgap width and the fast separation of photogenerated electron-hole pairs. This work brings a new idea to increase the photocatalytic hydrogen production capability of TiO2.

Strategies to enhance biohydrogen production from microalgae: A comprehensive review

Microalgae represent a promising renewable feedstock for the sustainable production of biohydrogen. Their high growth rates and ability to fix carbon utilizing just sunlight, water, and nutrients make them well-suited for this application. Recent advancements have focused on improving microalgal hydrogen yields and cultivation methods. This review aims to summarize recent developments in microalgal cultivation techniques and genetic engineering strategies for enhanced biohydrogen production. Specific areas of focus include novel microalgal species selection, immobilization methods, integrated hybrid systems, and metabolic engineering. Studies related to microalgal strain selection, cultivation methods, metabolic engineering, and genetic manipulations were compiled and analyzed. Promising microalgal species with high hydrogen production capabilities such as Synechocystis sp., Anabaena variabilis, and Chlamydomonas reinhardtii have been identified. Immobilization techniques like encapsulation in alginate and integration with dark fermentation have led to improved hydrogen yields. Metabolic engineering through modulation of hydrogenase activity and photosynthetic pathways shows potential for enhanced biohydrogen productivity. Considerable progress has been made in developing microalgal systems for biohydrogen. However, challenges around process optimization and scale-up remain. Future work involving metabolic modeling, photobioreactor design, and genetic engineering of electron transfer pathways could help realize the full potential of this renewable technology.

Flat-tube solid oxide stack with high performance for power generation and hydrogen production

This study presents the design, fabrication, and evaluation of a high-performance flat-tube solid oxide cell (FT-SOC) stack, which demonstrates exceptional power generation and hydrogen production capabilities. Comprising three large-sized FT-SOCs, each with an active area of 60 cm2, the stack was tested at 750 °C. It achieved a peak power density of 1.222 W/cm2 in fuel cell (FC) mode and an electrolysis current density of 1.283 A/cm2 at an average voltage of 1.3 V in electrolysis cell (EC) mode, marking the highest reported values for FT-SOC stacks to date. These results surpass the performance of most large-sized planar SOC stacks. Post-operation analysis revealed excellent interfacial contact between components, contributing to the stack's high performance. This study underscores the potential of FT-SOCs in efficient power generation and electrolytic energy storage applications, providing insights that could facilitate their industrial application.

Unveiling The Multifunction of Beaded Stream‐Like Co9Se8 Catalysts for Water Splitting, Reactive Oxygen Species Scavenging, and Hydrogen Anti‐Inflammation

AbstractThe electrocatalytic preparation of hydrogen at different pH values not only achieves excellent device performance but also promotes the application of reactive oxygen species (ROS) clearance and hydrogen anti‐inflammation. However, it is difficult to develop materials that simultaneously achieve these excellent properties. Herein, the preparation of beaded necklace‐like Co9Se8 microspheres using a general and facile synthetic strategy is reported. The Co9Se8‐modified electrode has three applications: efficient water splitting for enhanced performance, ROS scavenging, and hydrogen anti‐inflammatory activity. Experiments, high‐angle‐annular‐dark‐field scanning transmission electron microscopy, and density functional theory calculations indicate that the reconstructed Co(OH)2 plays a vital role in the oxygen evolution reaction and that the transition from *O to *OOH is the actual rate‐determining step. The Co9Se8 material, with its unique beaded necklace‐like structure, exhibits exceptional hydrogen production capabilities in phosphate buffer solution (pH 7.4). In particular, hydrogen produce under neutral conditions can effectively reduce ROS levels and significantly inhibit inflammation‐related pathological processes, playing a unique antioxidant and anti‐inflammatory role at the cellular level. The obtained results indicate that the as‐synthesized Co9Se8 is more suitable for water splitting, ROS scavenging, and hydrogen anti‐inflammatory applications, outperforming other transition metal electrodes and rendering practical industrial and clinical applications.

Improved All‐solid‐state Z‐scheme Photocatalytic System Based on TiO2/Ag−Pd/CdZnS

AbstractWe present an innovative Z‐scheme photocatalytic system, TiO2/Ag−Pd/Cd0.8Zn0.2S, exhibiting remarkable stability in aqueous solutions containing benzyl alcohol/acetic acid. Its performance rivals that of the benchmark Z‐scheme catalyst, ZnO/Pt/Cd0.8Zn0.2S. Thorough characterizations were performed using XRD, XPS, TEM, and UV‐Vis techniques, examining both the entire Z‐scheme system and its individual components, namely Ag−Pd/TiO2 and Cd0.8Zn0.2S. The standout performer, TiO2/Ag−Pd/Cd0.8Zn0.2S, demonstrated an apparent quantum yield (AQE) of 7 % within the 350–650 nm range. In contrast, AQEs for Ag−Pd/TiO2 and Cd0.8Zn0.2S were 0.6 % and 2.1 %, respectively, under identical conditions. Furthermore, we propose a charge transfer mechanism supported by femtosecond transient absorption spectroscopy (FTAS). This investigation not only introduces a stable Z‐scheme system with superior photocatalytic hydrogen production capabilities but also advances the FTAS technique for mechanistic exploration. In essence, our research paves the way for more efficient metal oxide/metal/Cd(Zn)S hybrid systems in the realm of photocatalysis.

Mathematical modelling and optimization of producing hydrogen-rich gas in COREX melter gasifier

The integration of dome injection technology and coal gasification technology can enhance space utilization and generate high-quality reducing gas in the dome of COREX melter gasifier, making it a promising process for hydrogen-rich gas production. In this study, a comprehensive 3-D mathematical model is utilized to depict the inner characteristics with dome coal injection, including flow filed, thermal state, gas composition and particle behavior in the dome of COREX melter gasifier. The results indicate that the flow field in the dome can be categorized into jet flow region, impinging flow region and plug flow region. The gasification performance exhibited significant improvement, particularly the hydrogen production capability, which increased by 2150 Nm3/h. The proportion of C(s) consumed by combustion decreased to 37.32 %, while that of gasification increased to 62.68 %. Without oxygen compensation, the optimal coal injection ratio is determined to be 204.5 kg/t. As the oxygen flow rate through the oxygen burners increases from 1478 Nm3/h to 4478 Nm3/h, the dome temperature rises, advancing the devolatilization process of coal particles and improving combustion efficiency. When CO2 is used as the alternative carrier gas, the proportion of CO in the export gas increases by 0.03 % and that of CO2 increases by 1.11 %. However, when H2O is used as the alternative carrier gas, the proportion of H2 in the export gas increases by 0.35 % and that of H2O increases by 0.89 %.

Time-averaged wind power data hides variability critical to renewables integration

Most publicly available wind data are aggregated to a temporal resolution of 30 or 60 min. This is adequate for some purposes, such as large-scale wind integration studies. However, the consequent loss of high-frequency power fluctuations from the data can significantly impact analysis on local and regional scales. The importance of this missing variability to the accurate assessment of renewables integration is increasingly being recognised as wind power is considered for energy autarky and local energy systems. Here, we investigate the statistics of the lost variability using two high-temporal-resolution datasets from France and the US. In particular, we focus on the likelihood that minimum and maximum thresholds are exceeded and illustrate the importance of sub-half-hourly variability for assessing sector-coupling applications, such as wind farm – electrolyser systems. We find that using half-hourly averaged turbine data can underestimate the occurrence of zero power by a factor of two. This matters if a wind turbine is coupled to an electrolyser, either directly or with only short-duration storage, because of dynamic operating constraints. The lower output limit means that half-hourly wind output could overestimate the hydrogen production and energy storage capabilities of alkaline electrolysers by up to 70 %.

Effects of multivalent ions on hydrogen production from the salinity gradient between desalination concentrated brine and river by reverse electrodialysis

In order to simultaneously produce hydrogen and reduce the salinity of concentrated wastewater (brine) from the desalination plant, a lab-scale reverse electrodialysis (RED) hydrogen production system driven by salinity gradient energy is designed and its performance is experimentally studied. The energy conversion of the RED system is found affected by the ionic compositions of the desalination concentrated brine (DCB). The effects of ionic types (multivalent cation, anion, and phosphorous salt) and ionic concentration (from 0.01 to 0.05 M) and pH of DCB (from 5 to 11) on the hydrogen production are investigated. The results show that the existence of multivalent ions in brine significantly degrade the capability of output voltage and hydrogen production of the RED system. Compared to the control group, the additions of 0.05 mol·L−1 NaBr and 0.05 mol·L−1 FeCl3 into the simulated brines lead to the output voltage drops of 29 % and 60 %, respectively, when the current is maintained at 0.2A. Additionally, the experiment yields an MHP of 128 mL·h−1 at the current of 0.3A. Generally, the performances of the RED stack can be improved as increasing the pH of an acidic DCB, but declined as the increasing the pH of an alkaline DCB.

A CMP-based [FeFe]-hydrogenase dual-functional biomimetic system for photocatalytic hydrogen evolution coupled with degradation of tetracycline

A novel bio-inspired conjugated microporous polymer (CMP) had been designed, synthesized and characterized. The mimics of [FeFe]-hydrogenase active sites were covalently attached to the CMP skeleton, which facilitates charge transfer between the light-harvesting moiety and active sites, and exhibited high performance in visible-light photocatalytic hydrogen evolution (2120 μmol·h−1·g−1) in an aqueous solution. The flower-like morphology, covalently linked framework and the “single active-site” effect derived from the porous skeleton were deemed to go a long way toward boosting the properties above. Interestingly, when the electron sacrifice agent (triethanolamine) was replaced by tetracycline, the CMP-based photocatalyst maintained the capability of photocatalytic hydrogen production (370 μmol·h−1·g−1) and realized efficient photodegradation of tetracycline simultaneously. This work provides a heuristic green dual-function strategy for constructing a sustainable and efficient photocatalytic system for hydrogen evolution with concurrent antibiotic residue degradation.