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A method for producing hydrogen from liquid benzene without CO 2 generation using plasma is proposed. A liquid plasma was emitted from the liquid reactant to crack liquid benzene to produce hydrogen. The only gaseous product was H 2 and no CO 2 was formed. Carbon crystals were produced as a solid product. To increase the decomposition efficiency of liquid benzene and the efficiency of hydrogen production, perovskite was applied as a catalyst. The reaction produced nano-sized carbon particles with hydrogen as the main product without impurities. The crystal size of carbon black was very small (<10 nm) and uniform. The carbon products were similar in crystal shape and size regardless of the reaction time. Liquid benzene is decomposed by active species in the liquid plasma to produce hydrogen and carbon without catalyst injection. When the perovskite catalyst was applied to the reaction using liquid plasma, the hydrogen production rate and carbon yield were significantly increased. Liquid benzene simultaneously produces hydrogen and carbon black through a decomposition reaction by liquid plasma. The LPP cracking process of liquid benzene can be evaluated as a 'green hydrogen' production technology that does not generate CO 2. [Display omitted] • A method was proposed for producing hydrogen from the decomposition of benzene using plasma. • Liquid benzene was decomposed into hydrogen and carbon by liquid plasma and photocatalyst. • Perovskites were applied as a photocatalyst to increase hydrogen production efficiency. • The products were hydrogen gas and carbon nanoparticles in this reaction, no CO 2 is formed. • Application of the perovskite catalyst significantly increased hydrogen production and carbon yield. [ABSTRACT FROM AUTHOR]

Ammonia is a promising material as a direct source of green hydrogen production. This paper reports a method for mass production of hydrogen from liquid NH 3 (NH 4 OH) through a photocatalytic decomposition reaction using liquid plasma. In this reaction, the highest hydrogen production rate was observed in the TiO 2 photocatalyst doped with N and metal ions as a photocatalyst sensitive to visible light with a low bandgap. At this time, the hydrogen production rate was obtained as about 142 L/g∙h. This is due to the high photoactivity of the visible light-sensitive photocatalyst in liquid plasma emitting strong visible light and ultraviolet light. The H 2 production rate obtained from the decomposition of liquid NH 3 by plasma discharge to the catalyst was higher than the H 2 production rate obtained from the NH 3 electrolysis process. [Display omitted] • Hydrogen production by liquid phase plasma was assessed in ammonium hydroxide solution. • The effects of irradiation of the liquid phase plasma were evaluated in the decomposition. • Modified TiO 2 was prepared by doping metal ions and nitrogen according to sol-gel method. • The highest rate of H 2 evolution obtained on the N- and Ni-codoped TiO 2 was about 142 L/g∙h. • The liquid-plasma emitting strong light led the high rate of H 2 production into the reactant. [ABSTRACT FROM AUTHOR]

Summary: A numerical model is developed to predict the methanol steam reforming for H2 production. This research designs an methanol steam reforming reactor and uses the Nelder‐Mead algorithm to find an equivalent steam tube radius by minimizing the error between the simulation and experimental data. The effects of three operating parameters (ie, inlet temperature, S/C ratio, and Reynolds number) on CH3OH conversion and H2 yield are discussed. Finally, the predictions of CH3OH conversion and H2 yield in terms of the operating parameters through neural networks are performed for finding the best combination of the operating parameter to maximize the H2 yield. After finding the equivalent radius from the simplified reactor, the evolutionary computation improves the prediction accuracy by 42.69%. For the operating parameters, an increase in temperature or S/C ratio intensifies the reforming performance, whereas the Reynolds number of 50 is more suitable for H2 production. A three‐step training and test of the database by the neural networks is adopted to evaluate the influence of the number of data sets and find the best combination of the parameters. The best combination poses the highest H2 yield of 2.905 mol (mol CH3OH)−1, and the error between the prediction and simulation is merely 0.206%. [ABSTRACT FROM AUTHOR]

Summary: There are various methods to produce hydrogen from water splitting as a substitute energy resource for fossil fuels in accordance with the global environmental crisis. Among these, water photocatalysis is considered one of the most renewable and sustainable processes simulated the solar energy utilized system in nature. During a half century, different kinds of photocatalysts were developed to convert photon energy into chemical energy to induce redox potential under visible light irradiation condition. In the beginning step, semiconductor materials, such as transition metal oxides, were explored extensively to use as a photocatalyst for hydrogen generation. However, semiconductor has limitations to act as an effective photocatalyst for water splitting due to the large band gap and recombination of charge carriers. Therefore, several kinds of modifications of structure or components have been studied to design visible light active photocatalysts for water splitting to generate hydrogen. Their performance was improved substantially by adding a noble metal or sensitizer to adjust the band gap and reduce the recombination of photoinduced charge carriers. Considering solar light‐induced photocatalytic hydrogen generation, various visible light active photocatalysts have been derived from carbon chain organic compounds and lattice crystals. This review classifies the visible light active photocatalysts as follows: (a) structural and chemical components of modified graphitic carbon nitride (g‐C3N4), (b) exfoliated perovskites, and (c) π‐bond conjugated polymers to produce hydrogen from water splitting. The hydrogen evolution efficiency of photocatalysts shows a great difference under visible light (λ > 400 nm) irradiation according to the three‐dimensional structure and electron transfer pathway. This is because the capability of restricting the recombination of photoinduced charge carriers and the band gap between the valence band and the conduction band of photocatalysts is dependent on the morphology and electrostatic interactions among components. This paper reviews visible light photocatalysts, that is, g‐C3N4 based materials, layered perovskites, and conjugated polymers, to provide integrated insight into photocatalytic water splitting to obtain hydrogen. [ABSTRACT FROM AUTHOR]

Ethanolamine released from a nuclear power plant was degraded by photocatalytic decomposition using plasma in the liquid phase with metal-incorporated photocatalysts. Metal-incorporated titanium dioxide photocatalysts were employed with carbon nanotubes and carbon nanofibers as a support. The photocatalytic decomposition of ethanol amine-contained water induced the degradation of ethanolamine and H 2 evolution, simultaneously. The degradation of ethanolamine and H 2 evolution were elevated by incorporating Ni on titanium dioxide nanocrystallites. The rate of H 2 evolution in the ethanolamine-containing water was higher than that in pure water, which was attributed to the additional H 2 evolution by the photodecomposition of ethanolamine in water. Image 1 • Ethanolamine released from a nuclear power plant was degraded by photocatalytic decomposition. • Liquid phase plasma was employed as a light source in the photocatalytic decomposition. • Photoreaction of ethanolamine wastewater led to the degradation of ethanolamine and H 2 evolution. • Degradation of ethanolamine were improved with the Ni loading on titanium dioxide photocatalyst. • Hydrogen evolution was increased significantly due to decomposition of ethanolamine. [ABSTRACT FROM AUTHOR]

This study examined the possibility of hydrogen production using a solution plasma process (SPP). The reactants were lignin model compounds and actual lignin oil. The highest amount of hydrogen was generated in SPP using m-cresol. The total amount of gas generated by the plasma reaction for 20 min using 23 g of m-cresol was 1.69 L, which comprised of 65.51% hydrogen and 29.85% CO. Furthermore, a maximum of 1.91 L of hydrogen was generated by a reaction between pyrolysis oil and ethanol with a weight ratio of 1:1. The presence of carbon black, a reaction byproduct, was measured by Fourier transform infrared spectroscopy, which revealed molybdenum trioxide peaks. It was confirmed that molybdenum used as an electrode was doped on carbon. • Hydrogen was produced from bio-oil using solution plasma process. • Guaiacol, m-cresol, and anisole were used as model bio-oil compounds. • Among model bio-oils, m-cresol achieved the highest hydrogen yield. • Lignin bio-oil with ethanol produced 1.91L hydrogen from solution plasma process. • Carbon black doped with electrode material was formed as byproduct. [ABSTRACT FROM AUTHOR]

A plasma in liquid state was applied as a light source in photocatalysis. The effects of liquid phase plasma irradiation were investigated for hydrogen evolution on the photocatalysts. The photocatalytic activities for hydrogen production from liquid phase plasma and UV light irradiation were compared. SrTiO3 perovskite photocatalysts which prepared by a sol‐gel method with high temperature calcining were introduced in the photocatalytic reaction. The effects of the metal loading on the perovskite photocatalysts were also evaluated in photocatalysis. A small amount of hydrogen was generated in the photo‐decomposition by irradiation of plasma into water without photocatalysts. The rate of hydrogen evolution by photocatalysis using plasma was increased on TiO2 and SrTiO3 perovskite photocatalysts. The photocatalytic activity was improved significantly with the metal loading on SrTiO3 perovskite photocatalysts. [ABSTRACT FROM AUTHOR]

In this study, a method for producing green hydrogen from ammonia water using plasma cracking was proposed. Solid acid catalysts, FAU and MFI zeolites, were used as catalysts. Zeolites were prepared by varying the Si/Al molar ratio to investigate the relationship between the acid sites of the catalyst and the reaction activity. The plasma was directly discharged into the ammonia water to generate hydrogen from the decomposition of ammonia. The gaseous products from the ammonia decomposition by plasma were mostly hydrogen with some nitrogen. No CO 2 was produced. Even when the catalyst was not injected, approximately 100 L/h of hydrogen was produced only by plasma discharge. The injection of the FAU or MFI zeolite catalysts improved the hydrogen production rate. The rate of hydrogen production obtained from the decomposition of ammonia water by catalyst and plasma irradiation was the highest for the FAU zeolite with the highest number of acid sites. The hydrogen production rate tended to increase in proportion to the number of acid sites in the catalyst. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, a process for producing hydrogen from liquid hydrocarbons by applying plasma is proposed. Toluene was decomposed by discharging a pulse-type plasma into liquid toluene directly. The changes in the rate of hydrogen production and reaction characteristics owing to injecting a perovskite catalyst were also investigated. A high hydrogen production rate of approximately 130 NL/h·g was obtained from the liquid–phase plasma reaction of toluene using the BiFeO 3 catalyst. The investigation into the reaction characteristics based on the plasma generation conditions indicated that the reaction was mainly affected by the plasma voltage. When titanium dioxide and perovskite (SrTiO 3 , BiFeO 3) photocatalysts were applied to this reaction, the reaction activities also varied depending on the light-absorption capacity of the catalysts. The highest hydrogen evolution rate was obtained using the BiFeO 3 catalyst, which absorbs visible light as well as UV light, compared with the TiO 2 photocatalyst, which absorbs only UV light. Because the plasma emission from toluene is predominantly in the visible region, the reaction activity was also determined to be the highest for the BiFeO 3 catalyst. The BiFeO 3 absorbs visible light up to about 550 nm, and it has a small bandgap energy of about 2.15 eV. This led to high photocatalytic degradation activity in visible light generated by plasma discharge in toluene. The carbon obtained had a particle size of less than 20 nm and purity of approximately 99%. • Photocatalytic decomposition of liquid toluene was conducted by liquid plasma on perovskite catalysts. • Pure hydrogen gas and carbon particles were simultaneously produced in the decomposition reaction. • BiFeO 3 perovskite exhibited a high hydrogen production rate due to its excellent visible light activity. • The produced carbon particles were small and uniform in nano size and had a large surface area. • The hydrogen production was greatly enhanced up to 130 NL/h·g in this cracking process. [ABSTRACT FROM AUTHOR]

[Display omitted] • The wastewater contained ethanolamine was decomposed using a liquid plasma and an electrolysis. • A hybrid reaction system linked to the liquid plasma and electrolysis was developed for H 2 production. • Performance of COD and total nitrogen removal was also investigated to the wastewater. • The COD and total nitrogen were removed entirely in the consecutive reaction process. • The H 2 evolution rate was increased significantly by decomposition in the hybrid system. The development of a hybrid reaction system linking photochemical decomposition with liquid-phase plasma and photocatalyst and electrolysis in a consecutive reaction was attempted for efficient decomposition and hydrogen production from high-concentration ethanolamine-resistant wastewater. A consecutive process was developed in which ethanolamine wastewater was decomposed completely by an electrolysis process after first reducing the concentration of ethanolamine by a decomposition reaction through liquid phase plasma and photocatalyst in the first step. The chemical oxygen demand (COD) and total nitrogen removal performance of wastewater containing ethanolamine were also investigated using the consecutive process. The COD and nitrogen removal efficiency were higher in the photochemical reaction by liquid plasma and bismuth ferrite photocatalyst than by electrolysis in a single reaction. In the hybrid reaction linking the two reactions, the COD and total nitrogen were removed entirely. The hydrogen production rates obtained from the photochemical reaction by liquid plasma and bismuth ferrite photocatalyst were higher than the respective hydrogen production rates obtained by a single electrolysis reaction. The hydrogen production rate obtained from the hybrid reaction system was increased significantly. Hydrogen produced by a photocatalytic reaction using liquid plasma and hydrogen produced by electrolysis could increase the overall hydrogen production rate. [ABSTRACT FROM AUTHOR]

This study examined the H2 production characteristics from a decomposition reaction using liquid-phase plasma with a bismuth ferrite catalyst. The catalyst was prepared using a sol–gel reaction method. The physicochemical and optical properties of bismuth ferrite were analyzed. H2 production was carried out from a distilled water and aqueous methanol solution by direct irradiation via liquid-phase plasma. The catalyst absorbed visible-light over 610 nm. The measured bandgap of the bismuth ferrite was approximately 2.0 eV. The liquid-phase plasma emitted UV and visible-light simultaneously according to optical emission spectrometry. Bismuth ferrite induced a higher H2 production rate than the TiO2 photocatalyst because it responds to both UV and visible light generated from the liquid-phase plasma. [ABSTRACT FROM AUTHOR]

Amorphous TiO2 doped with N was characterized by its photocatalytic activity under visible light irradiation. The amorphous N-doped TiO2 was prepared by the sol-gel method through heat treatment at a low temperature. The photocatalyst showing activity in visible light despite heat treatment at low temperature can be applied to plastics and has excellent utility. The N-doped TiO2 appeared amorphous when heat-treated at 130 °C. It was converted into an anatase-type N-doped TiO2 when this was calcined at 500 °C. The photocatalyst showed photocatalytic activities in the photocatalytic decomposition of formaldehyde and methylene blue under visible light irradiation. The photocatalyst exhibited a higher rate of hydrogen production than that of TiO2 in photocatalytic decomposition of water under liquid-phase plasma irradiation. The bandgap of the amorphous N-doped TiO2 measured by investigation of optical properties was 2.4 eV. The lower bandgap induced the photocatalytic activities under visible light irradiation. [ABSTRACT FROM AUTHOR]

Hydrogen production from water was investigated by applying liquid plasma (LPP) to photocatalytic splitting of water. The optical properties of LPP due to water emission were also evaluated. The correlation between the optical properties of plasma and the formation of active species in water was investigated with the photocatalytic activity of hydrogen production. TiO 2 was also doped with Ag to evaluate the effect of enhancing photocatalytic activity. The photocatalytic activity was evaluated by the rate of hydrogen production, and the effect of hydrogen formation was also investigated by injecting methanol as an additive. As a result of examining the luminescence properties of LPP, it showed high luminescence in the 309 nm UV region and the 656 nm visible region. The hydrogen doping rate was increased in the Ag-doped TiO 2 photocatalyst. Ag-doped TiO 2 has wider light absorption into the visible region and narrower band gap. Due to these properties, the rate of hydrogen generation is superior to TiO 2 photocatalysts. The photochemical reaction with LPP and photocatalyst in aqueous solution with CH 3 OH showed a significant increase in hydrogen production rate. The increase in hydrogen production by injection of additives is because the optical properties of generating OH radicals are improved and CH 3 OH is decomposed to act as an electron donor to improve hydrogen production. • Effect of plasma irradiation into water on water photolysis was evaluated for hydrogen evolution. • Range of light absorption became wider and bandgap reduced by Ag doping on TiO 2 surface. • The rate of hydrogen evolution was increased by the Ag doping on the TiO 2 surface. • The optical properties of generating OH radicals are enhanced by the injection of additives. • Hydrogen evolution was remarkably increased with addition of methanol into water. [ABSTRACT FROM AUTHOR]

This study examined the effects of Ni loading on different types of alumina (γ-Al 2 O 3 , mesoporous Al 2 O 3 , 13 nm-sized Al 2 O 3 , and <50 nm-sized Al 2 O 3) for high-density polyethylene gasification for enhanced hydrogen generation. The catalytic activity of Ni loaded alumina was observed in the order of 13 nm-sized Al 2 O 3 > mesoporous Al 2 O 3 > (<50 nm-sized Al 2 O 3) > γ-Al 2 O 3 for the gas yield and γ-Al 2 O 3 > (<50 nm Al 2 O 3) > mesoporous Al 2 O 3 > 13 nm Al 2 O 3 for the oil yield, respectively. In addition, the production of hydrogen from Ni loaded alumina showed an increasing trend in the order of (<50 nm-sized Al 2 O 3) > γ-Al 2 O 3 > 13 nm-sized Al 2 O 3.> mesoporous Al 2 O 3. In contrast, CO showed the trend as Ni/mesoporous Al 2 O 3 > Ni/13 nm-sized Al 2 O 3 > Ni/γ-Al 2 O 3 > (Ni/<50 nm Al 2 O 3). The highest level of hydrogen production from the Ni/<50 nm-sized Al 2 O 3 catalyst might be because of its highest Ni dispersion and surface area. The use of Ni-loaded nm-sized alumina could be an excellent method for increased hydrogen production compared to other types of alumina available. • 4 different Ni/alumina catalysts were applied to HDPE gasification. • γ-Al 2 O 3 , mesoporous Al 2 O 3 , 13 nm-sized Al 2 O 3 , and (<50 nm-sized Al 2 O 3) were used. • The highest level of hydrogen was produced from the Ni/<50 nm-sized Al 2 O 3 catalyst. • Ni/<50 nm-sized Al 2 O 3 catalyst showed highest Ni dispersion and surface area. [ABSTRACT FROM AUTHOR]

[Display omitted] • •Decomposition of liquid hydrocarbons induced by liquid plasma and photocatalyst was conducted. • •H 2 and carbon were simultaneously produced in the decomposition of liquid hexane and benzene. • •Only H 2 was obtained as a gaseous product, and no CO 2 was produced in this reaction. • •Carbon particles produced from the decomposition were small and uniform, with a size of 10 nm or less. • •The BET surface area of the carbon produced in this reaction was greater than 500 m2/g. A study was conducted on the decomposition reaction of liquid hydrocarbons induced by liquid plasma and photocatalyst. This study is to obtain useful resources by recycling waste liquid-hydrocarbons. Titanium dioxide and TiO 2 -doped with a metal (and nitrogen atoms) were used as photocatalysts individually in the study. First, H 2 and carbon were simultaneously produced in the decomposition reaction of liquid hexane and benzene induced by liquid plasma. Notably, only H 2 was obtained as a gaseous product, and no carbon dioxide was produced in this reaction. However, when photocatalyst was injected into this decomposition, the corresponding reactivity improved. In particular, the amount of H 2 and carbon produced increased in the order of: the amount of H 2 and carbon produced with N/Ni/TiO 2 > Ni/TiO 2 > TiO 2 photocatalyst, respectively, when the photocatalyst was added in an equal amount to the reactant of the decomposition. The highest carbon yield and hydrogen evolution under these experimental conditions were about 1 %/(g∙h) and about 180 L/(g∙h), respectively. This order is because the strong visible light generated by liquid plasma discharge improved the photoreactivity of the N/Ni/TiO 2 photocatalyst that has a high sensitivity to visible light and narrow band gap. Carbon particles produced from the decomposition reaction of liquid hexane and benzene, respectively, induced by liquid plasma and photocatalyst were small and uniform, with a size of 10 nm or less. In addition, the BET surface area of the carbon produced in this reaction was greater than 500 m2/g, and the properties of the carbon particles were almost the same regardless of the lapse of reaction time. Hence, this decomposition reaction of liquid hexane and benzene, respectively, induced by liquid plasma and photocatalyst was judged to be forming an efficient technology that can simultaneously obtain high-purity hydrogen energy and useful basic materials from liquid hydrocarbons. [ABSTRACT FROM AUTHOR]

Ammonia can be applied as a hydrogen carrier and used directly as a hydrogen production supply. In this paper, a technique for mass-producing hydrogen from ammonia water is proposed by applying a liquid phase plasma (LPP) discharge technique and a photocatalyst. In this reaction, N- and Fe ion codoped TiO 2 (N/Fe/TiO 2) photocatalysts were prepared and applied as a visible light-sensitive photocatalyst. N/Fe/TiO 2 (NFT) had a similar crystal shape and size to anatase TiO 2 , but the surface was doped with metal ions. The bandgap of the NFT photocatalyst obtained from the spectrum measured by photoluminescence spectroscopy was approximately 2.4 eV. Nitrogen and Fe ions played a role in narrowing the gap between the conduction band (CB) and valence band (VB) of TiO 2 , effectively reducing the bandgap. In the decomposition reaction of ammonia water by LPP irradiation, the NFT photocatalyst showed the highest hydrogen evolution rate. The amount of hydrogen produced from ammonia water by LPP irradiation on the NFT photocatalyst was approximately 133 L/h. The hydrogen production rate obtained from ammonia water by the photocatalyst and LPP irradiation was significantly higher than that obtained by the ammonia electrolysis process. • Photocatalytic hydrogen production by liquid phase plasma was assessed in ammonia water. • The effects of irradiation of the liquid phase plasma were evaluated over TiO 2 photocatalyst. • N/Fe/TiO 2 was employed as a visible light sensitive photocatalyst with N and Ni codoping. • The rate of H 2 evolution from NH 4 OH by the reaction system was approximately 133 L/h. • The rate of hydrogen evolution was significantly higher than that obtained by electrolysis. [ABSTRACT FROM AUTHOR]

Interior modification through preferential substitution of heteroatoms in 2D materials can rescue surface reactive sites for enhanced charge kinetics and photo-activity. Here, Ru and Ni heteroatoms were successfully incorporated in ZnIn 2 S 4 (ZIS) nanosheets via a simple hydrothermal technique. Ru-ZIS photocatalysts exhibited improved photo–water splitting activity (26,400 µmol. h−1g−1) and good stability than that of Ni-ZIS and pristine ZIS under simulated sunlight, which may be related to the increase in reactive sites with Ru substitution, optimized adsorption-free energy of the reaction intermediates and charge kinetics. Ru substitution influenced Zn site availability and thus coordinated bonding with surrounding S ions. Ru-ZIS showed excellent hydrogen evolution performance and minimal change in Gibbs free energy (ΔGH, ∼0 eV). By analyzing the density of states, both Ru and S sites had greater H* intermediate absorption abilities. This study elaborates on the effect of preferential heteroatom substitution on photocatalytic performance and has widespread applications. [Display omitted] • Single-component metal-doped ZIS nanosheet synthesized in a one-step method. • Substitution with Ru promoted photocatalytic H 2 production and stability. • Ru replaced Zn sites in ZIS lattice, compared to the Ni replacement of In sites. • Ru promoted electron migration to reactive sites via Schottky barrier. [ABSTRACT FROM AUTHOR]

Hydrogen production from water splitting is considered one of the most environmentally friendly processes for replacing fossil fuels. Among the various technologies to produce hydrogen from water splitting, thermochemical cycles using chemical reagents have the advantage of scale up compared to other specific facilities or geological conditions required. According to thermochemical processes using chemical redox reactions, 2-, 3-, 4-step thermochemical water splitting cycles can generate hydrogen more efficiently due to reducing temperatures. Increasing the number of cycles or steps of thermochemical hydrogen production could reduce the required maximum temperature of the facility. In addition, recently developed hybrid thermochemical processes combined with electricity or solar energy have been studied on a large scale because of the reduced cost of hydrogen production. Additionally, hybrid thermochemical water splitting combined with renewable energy can result in not only reducing the cost, but also increasing hydrogen production efficiency in terms of energy. As for a green energy, hydrogen production from water splitting using sustainable and renewable energy is significant to protect biological environment and human health. Additionally, hybrid thermochemical water splitting is conducive to large scale hydrogen production. This paper reviews the multi-step and highly developed hybrid thermochemical technologies to produce hydrogen from water splitting based on recently published literature to understand current research achievements. • Thermochemical hydrogen production from water splitting is viable on a large scale. • The multi-step thermochemical method can be an energy-saving process. • Hybrid methods are plausible in terms of cost and efficiency. • Renewable energy combined system is conducive to hydrogen production. [ABSTRACT FROM AUTHOR]

Different types of cobalt-based mixed oxide catalysts (20 wt%Co/MgO, 5 wt%Cu-20 wt% Co/MgO, 20 wt%Co/50%MgO–50%Al 2 O 3) were synthesized by the co-precipitation method and applied for hydrogen production from glycerol steam reforming. The catalysts were characterized using X-ray diffraction (XRD), H 2 -Temperature-programmed reduction (H 2 -TPR), CO 2 -Temperature Programmed desorption, CO-Chemisorption, and CHN techniques. The H 2 -TPR analysis showed the reducibility of cobalt-oxide (5Cu20CM; 5 wt%Cu-20 wt% Co/MgO) was enhanced by the copper, and reduction profiles of cobalt oxide shifted to a lower temperature (<450 °C). Among the catalysts, 5Cu20CM showed a maximum yield of hydrogen (74.6%) with 100% conversion of glycerol to the gaseous phase. The superior catalytic performance of 5Cu20CM for glycerol conversion was attributed to the smaller particle size (7 nm), higher dispersion of cobalt (35.0%), and the higher surface area (56 m2/g) of cobalt metal. Furthermore, Raman spectroscopy of the spent catalysts confirmed that the copper promoted cobalt-magnesium catalyst suppressed the carbon formation, consequently, 5Cu20CM catalyst showed a stable performance up to 30 h. • Co-based catalysts by coprecipitation method were used for glycerol steam reforming. • The addition of pure MgO is encouraged to obtain stable hydrogen yield. • The 5 wt% Cu- 20 wt%Co/MgO reported the highest yield of hydrogen as 74.6%. • Cu addition suppressed coke formation due to smaller particles of Co. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni-loaded Zr 0.6 Ce 0.4 O 2 has the best performance for the steam gasification process. • Ce doping in ZrO 2 significantly increased H 2 selectivity. • Synergism between Ni/Zr 0.6 Ce 0.4 O 2 and microreactor enhanced H 2 production. • The spent coffee steam gasification was performed to produce H 2 -rich gas. • Gas yield and H 2 selectivity were maximized using monolithic catalysts. To produce H 2 -rich gas, steam gasification of spent coffee grounds is performed in this study by applying Zr x Ce 1-x O 2 supports (x = 0.2, 0.6) in a monolithic reactor. Compared with conventional Ni/γ-Al 2 O 3 , Ni/ZrxCe 1-x O 2 catalysts offer higher gas yields and H 2 generation. In particular, Ni/Zr 0.6 Ce 0.4 O 2 exhibits the highest gas yield (86.32 wt%), H 2 selectivity (56 vol%), and low coke formation owing to its favorable Ni dispersion, high oxygen mobility, and completely homogeneous nanometer-sized morphology. A significant increase in gas yield was observed in the monolith reactor (M@Ni/Zr 0.6 Ce 0.4 O 2) compared to the fixed bed reactor (F@Ni/Zr 0.6 Ce 0.4 O 2), from 74.85 wt% to 86.32 wt%. H 2 selectivity (56.87 vol%) is also increased, which can be associated with the unique properties of the monolithic reactor. This phenomenon is attributed to the increase in residence time and the amount of mass and heat transfer between the catalyst and vapor, which favorably direct the selectivity toward H 2. The use of metal-oxide composite supports, especially Ni/Zr 0.6 Ce 0.4 O 2 catalyst, effectively alleviated coke formation (0.7 wt%), whereas the amount of coke produced by Ni/γ-Al 2 O 3 (2.4 wt%) was more than three times higher. Overall, exploiting the remarkable benefits of Zr x Ce 1-x O 2 (x = 0.2, 0.6) composite oxides as supports for Ni catalyst and monolithic reactors would have an emerging outlook for H 2 generation via gasification technology. [ABSTRACT FROM AUTHOR]

• A new sustainable platform for plastic waste/CO 2 to syngas was investigated. • Catalytic pyrolysis promoted conversion of fishing net waste to syngas under CO 2 /N 2. • Coke formation resulted in Ni catalyst deactivation, but CO 2 suppressed it. • Continuous use of Ni catalyst under CO 2 was allowed for high production rate of H 2. A benign route for hydrogen (H 2) production is environmentally desirable. To achieve this, H 2 synthesis from polymeric waste was investigated. A new route was sought to maximize H 2 production with the least formation of coke during catalytic pyrolysis of fishing net waste (FNW) by using CO 2 (as reaction media) and a Ni/SiO 2 (as catalyst). The thermolytic characteristics of FNW were also evaluated under the CO 2 condition (and N 2 as reference environment) both with and without catalysts to assess the full scope of variabilities involved in catalytic pyrolysis of FNW. The use of Ni/SiO 2 catalyst in each of the N 2 and CO 2 conditions improved the reaction kinetics in terms of syngas formation with significant production of H 2 (1,543 and 770 mmol g−1 cat h−1) and CO (11 and 1157 mmol g−1 cat h−1), respectively. However, H 2 production rate dropped when the catalyst was deactivated due to (hydro)carbon deposition onto the catalyst surface under N 2 environment. Under CO 2 environment, CO 2 served as an oxidant during FNW thermolysis with additional CO formation and prolonged lifetime of catalyst (via suppressed deactivation). H 2 production mediated by CO 2 increased to ≥1,093 mmol g−1 cat h−1 during five repeated cycles of FNW pyrolysis, coupling with water–gas shift reaction (WGS: CO + H 2 O ⇌ H 2 + CO 2). This new approach to H 2 production is demonstrated as a practical measure for producing H 2 while extending catalyst life. [ABSTRACT FROM AUTHOR]

Water splitting from wastewater has been in the limelight because it has advantages which are hydrogen production and electrochemical oxidation at the same time. For efficient water splitting even in wastewater condition, water splitting electrodes should have cost-effectiveness and high durability. Here, we fabricated highly stable and electrocatalytic graphene on copper-nickel alloy to electrochemically produce hydrogen from wastewater in presence of carbon layer between nickel and copper. The electrode fabrication was performed by alloying the copper with nickel and growing graphene on the surface at the same time. The copper and nickel contents of electrode surface were kept by carbon layer hindering the metal diffusion at high temperature. Highly electrocatalytic activity (onset potential = 95 and 158 mV, Tafel slope = 58 and 80 mV dec−1), high durability and pH independence of graphene on copper-nickel alloy were confirmed in acidic and alkaline wastewater containing formaldehyde. Image 1 [ABSTRACT FROM AUTHOR]

• Hydrogen production methods through ammonia dehydration are introduced. • Applicable ammonia dehydration technologies are critically reviewed. • Research opportunities and needs to improve each technology for future application are discussed. Hydrogen (H 2) is considered one of the most promising alternative energy resources instead of fossil fuels, serving as a clean energy carrier. Ammonia (NH 3) is regarded as a high percentage hydrogen carrier and utilized as an initial material for H 2 production. As for the H 2 production through NH 3 decomposition, there are various catalytic processes particularly using Ru- and Pd-based catalysts. The Ru- and Ni-based NH 3 decomposition catalysts have been studied due to synergetic effect of active metal phase in stabilizing unstable nitrogen intermediate species during NH 3 decomposition reaction. The Pd catalyst-based membrane reactors were developed to enhance H 2 separation from the product stream of NH 3 decomposition. Integrated systems combining Ru catalyst and Pd-based membrane were also explored to achieve a high yield of H 2 from NH 3. This review summarizes recent literatures on catalytic NH 3 decomposition to produce H 2. It probably provides useful insights into designing large-scale H 2 production processes. [ABSTRACT FROM AUTHOR]

Carbon black is produced with H 2 gas from a benzene solution using the liquid-phase precipitation (LPP) mathod. Subsequently, the carbon black is heat-treated and applied as a conductive material for a supercapacitor to evaluate its performance. Carbon black produced as primary particles by the LPP reaction aggregates and grows into a secondary structure, and then crystallizes through heat treatment to form multi-polygonal nanoshells. The electrical conductivity of carbon black increased by heat treatment, but when the temperature exceeded 1500 °C, the electrical conductivity rather decreased. Following heat treatment at 1500 °C, the electrode used as the conductive material exhibits the largest specific capacitance value and the smallest IR drop. As the carbon black produced via the LPP method exhibits better conductive properties than those of Super-P, the potential to use the present method as a new hydrogen production method is confirmed. [Display omitted] • Production of hydrogen and carbon black from benzene by LPP method. • Formation of graphitized multiple nanoshells by heat treatment. • The electrical conductivity of carbon black heat-treated at 1500 °C was the highest. • Heat treatment at 1500 °C gave the largest capacitance and the smallest IR drop. • The economic feasibility of producing hydrogen with LPP was secured. [ABSTRACT FROM AUTHOR]

[Display omitted] • The air gasification of furniture waste sawdust was conducted to produce H 2. • Spinel-type oxides-supported Ni catalysts showed high activity for H 2 production. • Growing temperature enhanced the gas yield while slight effect on H 2 selectivity. • Changing the C/F ratio from 1/5 to 1/20 gently affected the catalysts' efficiency. Furniture waste sawdust, as a byproduct of the furniture industry, is discharged in huge amounts annually. However, traditional strategies applied for their treatment have resulted in crucial environmental issues. As an eco-friendly alternative option to treat Furniture waste sawdust, this study developed a catalytic gasification technology using spinel-type oxide (AB 2 O 4)-supported Ni catalysts under an air atmosphere to generate H 2 -rich gas. To this end, different metals are substituted as A cation in the spinel structure, followed by wash-coating on the monolithic reactor and impregnation with Ni to prepare Ni/MAl 2 O 4 (M = Ca, Co, Ba, Zn, Zr, Mg, or Cu) catalysts. The employment of catalysts greatly enhanced the gas yield and H 2 and CO selectivities, while significantly reducing the CO 2 , CH 4 , and C 2 -C 4 generation, attributable to stimulated dry- and steam-methane reforming reactions. In particular, the highest gas yield (81.67 wt%) and H 2 selectivity (32.19 vol%), lowest CO 2 , and almost zero CH 4 and C 2 -C 4 contents are obtained over Ni/CoAl 2 O 4 catalyst, owing to the high oxygen transfer potential, appropriate basicity, and high Ni dispersion. Furthermore, a considerably enhanced gas yield and slightly increased H 2 selectivity are observed when the gasification temperature is increased from 700 to 800 °C, reaching the maximum at 87.31 wt% and 32.87 vol%, respectively. Moreover, different catalyst-to-feedstock ratios from 1/5 to 1/20 gently influenced the gas yield and composition. Overall, the emerging potential of monolithic spinel-type oxide-supported Ni catalysts for hydrocarbon cracking, along with the use of waste materials as feedstock, can open new prospects for the economical and eco-friendly generation of H 2 via gasification technology." [ABSTRACT FROM AUTHOR]

Enhanced hydrogen production by photocatalytic decomposition was assessed using liquid phase plasma over metal-loaded photocatalysts. Effects of irradiation of the liquid phase plasma were evaluated in the photocatalytic hydrogen production of hydrogen. Carbon nanofiber was introduced as photocatalytic support for the Ni-loaded TiO 2 photocatalyst. The influence of addition of organic reagents into water on hydrogen evolution was also evaluated. The photocatalytic decomposition by irradiation of the liquid phase plasma without photocatalyst produced some hydrogen evolution. The rate of hydrogen evolution was improved by the metal loading on the TiO 2 surface. The carbon nanofiber acted as a useful photocatalytic support for the fixation of TiO 2 . Hydrogen evolution was enhanced by the Ni loading on the TiO 2 nanocrystallites supported on the carbon nanofiber support. Hydrogen evolution was increased significantly by the addition of organic reagents, which acted as a type of sacrificial reagent promoting photocatalysis. [ABSTRACT FROM AUTHOR]

Hydrogen evolution by water photocatalysis using liquid phase plasma system was disserted over metal-loaded TiO 2 photocatalysts. Carbon nanotube was applied as a support for the metal-loaded TiO 2 nanocrystallites. Photocatalytic activities of the photocatalysts were estimated for hydrogen production from water. Hydrogen was produced from the photodecomposition of water by liquid phase plasma irradiation. The rate of hydrogen evolution was improved by the metal loading on the TiO 2 surface. TiO 2 nanocrystallites were incorporated above 40 wt% onto the carbon nanotube support. The carbon nanotubes could be applied as a useful photocatalytic support for the fixation of TiO 2 . Hydrogen evolution was enhanced by the Ni loading on the TiO 2 nanocrystallites supported on the carbon nanotube. Hydrogen evolution was increased apparently with addition of the alcohols which contributes as a kind of sacrificial reagent promoting the photocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Taguchi and response surface methodologies for ethanol reformation are reviewed. • The optimum temperatures for ethanol steam reforming are higher than 500 °C. • The optimum temperatures for ethanol autothermal reforming are higher than 700 °C. • A steam-to-carbon ratio of 5 mol.mol−1 is optimum for hydrogen production. • Ethanol steam reforming is more efficient than ethanol autothermal reforming. Hydrogen production from bioethanol has garnered significant research attention due to its renewability, sustainability, and net zero emission. This research aims to review two statistical optimization techniques, response surface methodology (RSM) and the Taguchi method, for hydrogen production from ethanol thermochemical conversion. The RSM model demonstrated that temperature increases hydrogen production, which peaked between 500 °C and 600 °C for ethanol steam reformation (ESR) and >700 °C for ethanol autothermal reforming (ATR) processes. Maximum hydrogen synthesis occurs at steam-to-ethanol (S/E) ratios of 3–5 mol.mol−1 for both ethanol steam and autothermal reforming. Adding oxygen, a characteristic parameter of autothermal reforming, reduces hydrogen production. Ethanol autothermal reforming may be less efficient than ethanol steam reforming for hydrogen production. The impacting parameters for ethanol reforming identified by Taguchi techniques are steam-to-carbon ratio, ethanol steam reforming temperature, and water–gas shift reaction temperature, where steam-to-carbon ratio and ethanol steam reforming regulate hydrogen production substantially. The Taguchi approach reveals that an ethanol flow rate of 2 cm3.min−1, a steam-to-carbon ratio of 5, and an ethanol steam reforming temperature of 500 °C are optimal reaction conditions. Optimization strategies improve biohydrogen production and make the following reaction more precise. For example, only optimization approaches can determine if a parameter should be reinforced or lowered. [ABSTRACT FROM AUTHOR]

Photocatalytic decomposition of acetaldehyde-contained wastewater was assessed for the degradation of pollutants and the production of hydrogen. Liquid phase plasma was applied in the photoreaction as a light source. The evolution of hydrogen and acetaldehyde degradation were characterized by the photocatalytic decomposition system. Ni-loaded TiO 2 photocatalysts and various porous materials were introduced to the photocatalytic reaction. The photochemical decomposition by irradiation of the liquid phase plasma without photocatalysts produced some hydrogen evolution with the degradation of acetaldehyde, which was attributed to the decomposition of the reactant by active species generated by the irradiation of liquid phase plasma. The Ni loading on TiO 2 brought out an enhancement of acetaldehyde degradation and hydrogen evolution. In the photocatalysis of acetaldehyde-contained wastewater using the liquid phase plasma, hydrogen evolution was accelerated due to the additional hydrogen production by the photocatalytic decomposition of acetaldehyde. The porous materials could be used as an effective photocatalytic support. MCM-41 mesoporous material has acted as a highly efficient photocatalytic support to the TiO 2 photocatalyst. [ABSTRACT FROM AUTHOR]

Egg-shell-type pellet catalysts were prepared by selectively placing nickel and/or ruthenium on the outer region (shell) of alumina pellets so that the active components can be utilized effectively in steam methane reforming (SMR) reaction with high gas-hourly space velocity conditions. To ensure the reproducibility of catalyst preparation, we evaluated two types of commercial alumina pellets. And, we finally selected one commercial alumina pellet, which had uniform pores distribution. The thickness of the ruthenium-shell can be controlled by optimizing the evaporation temperature and rotating speed while preparing an ‘egg-shell-type’ 1 wt. % Ru/alumina catalyst. When applied to a SMR reaction, as the space velocity of the reactant increased in SMR reaction, ‘egg-shell-type’ 1 wt. % Ru/alumina catalyst showed a higher methane conversion than a ‘homo-type’ 1 wt. % Ru/alumina pellet catalyst, in which the active metal was uniformly dispersed in the whole region of pellet. Since ruthenium is a costly noble metal, we prepared a Ni/Ru bimetal catalyst [‘egg-shell-type’ 5 wt. % Ni/0.7 wt. % Ru bimetal catalyst] substituting nickel for some portion of the ruthenium in order to increase the economic feasibility. The bimetal Ni/Ru catalyst showed even better CH 4 conversion than the egg-shell-type catalyst containing ruthenium only. We also confirmed that the egg-shell-type catalyst effectively utilized its active components in the SMR reaction. [ABSTRACT FROM AUTHOR]

• The steam gasification of microalgae was carried out to obtain H 2 -rich gas. • Ni-perovskite oxide catalysts showed a high catalytic effect toward H 2 generation. • The synergetic effect of metallic Ni and perovskite elements was observed. • The elevating temperature was conducive to enhancing gas yield and H 2 selectivity. Steam gasification of microalgae upon perovskite oxide-supported nickel (Ni) catalysts was carried out for H 2 -rich gas production. Ni-perovskite oxide catalysts with partial substitution of B in perovskite structures (Ni/CaZrO 3 , Ni/Ca(Zr 0.8 Ti 0.2)O 3 , and Ni/Ca(Zr 0.6 Ti 0.4)O 3) were synthesized and compared with those of the Ni/Al 2 O 3 catalyst. The perovskite oxide supports improved Ni dispersion by reducing the particle size and strengthening the Ni-support interaction. Higher gas yields and H 2 selectivity were obtained using Ni-perovskite oxide catalysts rather than Ni/Al 2 O 3. In particular, Ni/Ca(Zr 0.8 Ti 0.2)O 3 showed the highest activity and selectivity for H 2 production because of the synergetic effect of metallic Ni and elements present in the perovskite structures caused by high catalytic activity coupled with enhanced oxygen mobility. Moreover, increasing the temperature promoted the yield of gas and H 2 content. Overall, considering the outstanding advantages of perovskite oxides as supports for Ni catalysts is a promising prospect for H 2 production via gasification technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • The production of green H 2 from biomass valorization by gasification was explained. • The gaseous product of gasification is intensely affected by experimental conditions. • Steam has been known as the most efficient gasifying agent for the H 2 production. • Functional mechanism of catalyst affects the gasification efficiency and H 2 yield. • Technical and economic obstacles should be solved for gasification commercialization. Green and sustainable hydrogen from biomass gasification processes is one of the promising ways to alternate fossil fuels-based hydrogen production. First off, an overview of green hydrogen generation from biomass gasification processes is presented and the corresponding possible gasification reactions and the effect of respective experimental criteria are explained in detail. In addition, a comprehensive explanation of the catalytic effect on tar reduction and hydrogen generation via catalytic gasification is presented regarding the functional mechanisms of various types of catalysts. Furthermore, the commercialization aspects, the associated technical challenges and barriers, and the prospects of a biomass gasification process for green hydrogen generation are discussed. Finally, this comprehensive review provides the related advancements, challenges, and great insight of biomass gasification for the green hydrogen generation to realize a sustainable hydrogen society via biomass valorization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni-USY catalysts were applied in FW gasification to produce H 2 -rich syngas. • The greatest gas yield and biohydrogen selectivity was obtained from Ni-USY(5). • Maximum biohydrogen production yield was achieved by a 20 wt% Ni loading. • Raising temperature (up to 800 ℃) led to enhancement of biohydrogen production. This is the first study on air gasification of furniture waste (FW) over Ni-loaded ultra-stable Y-type zeolites (Ni-USY) to produce biohydrogen. Effects of SiO 2 /Al 2 O 3 ratio of USY (5, 30, and 60), Ni loading (5, 10, 20, and 30 wt%) onto the support, and reaction temperature (700, 750, and 800 °C) on catalytic air gasification were investigated. The Ni-USY(5) led to a relatively higher gas yield (72.19 wt%) and higher volume percent of H 2 (31.94 vol%) and CO (34.57 vol%) and lower CH 4 and C 2 -C 4 yields than the Ni-USY(30) and Ni-USY(60). An increase in the Ni loading onto USY(5) support from 5 wt% to 30 wt% did not affect the yield of gas. The concentrations of H 2 (41.16 vol%) and CO (38.62 vol%) increased as increasing Ni loading from 5 wt% to 20 wt%. The H 2 and CO concentrations significantly decreased as the Ni loading became over 20 wt%. Increasing the temperature from 700 to 800 °C increased the yields of H 2 and CO and decreased the yields of CO 2 , CH 4 , and C 2 -C 4. The contents of harmful compounds (e.g., benzene derivatives, phenolics, and polycyclic aromatic hydrocarbons) in liquid product were suppressed when using the Ni-USY(5). The air gasification with the Ni-USY catalysts could offer as an emerging technology to transform FW to H 2 -rich syngas with low contents of harmful pollutants. [ABSTRACT FROM AUTHOR]

• The hydrogen production from water electrolysis is very efficient. • The metal based single-layered atomic dispersed electrocatalyst are introduced. • Noble metal free nanostructured metal component electrocatalysts are explained. • Graphene based electrocatalysts are compared. • Bifunctional electrodes using metal sulfides and phosphides are introduced. Hydrogen is one of the most promising alternative energy resources of fossil fuels. Among the many ways to generate hydrogen gas, electrochemical water splitting is more feasible and renewable. Compared to processes using solar energy for a specific geological environment or thermochemical decomposition at high temperatures, the electrocatalysis of water can produce hydrogen without the restriction of geological conditions and scale-up facilities. Water is one of the most renewable and sustainable resources to obtain hydrogen. On the other hand, water splitting into hydrogen and oxygen is thermodynamically unfavorable under the atmospheric condition. Therefore, novel materials are needed to produce hydrogen from water splitting using electrocatalysts. Recently, various state-of-the-art technologies and catalysts have been developed in the electrocatalysis of water to produce hydrogen. Among the litany of novel materials, according to the preparation method and morphology of electrocatalysts, the hydrogen production efficiency from water splitting shows great differences. This paper recently reported efficient electrocatalysts for water splitting using multi-component catalysts composed of several metals, organic polymer, metal sulfides, and metal phosphides. In addition, the essential principles for an investigation regarding more efficient hybrid electrocatalysts for water splitting as a renewable and sustainable hydrogen producing method can be determined. [ABSTRACT FROM AUTHOR]

The disposal of food waste (FW) is a major cause of environmental contamination. This study reports an environmentally friendly FW disposal method in the form of catalytic steam gasification using various types of Ni-loaded chars (untreated char, steam-treated char, and ZnCl 2 -treated char). The results were also compared with the gasification results from the Ni catalysts supported on commercial α-alumina (Ni/α-Al 2 O 3). The Ni/steam-treated char showed the maximum hydrogen generation (0.471 mol/(g feedstock•g cat)) because of the high reducibility, high nickel dispersion, large amount of inherent K and Ca, and moderate surface area. The overall gas and H 2 yield were observed in the following order: Ni/steam-treated char > Ni/ZnCl 2 treated char > Ni/untreated char > Ni/α-Al 2 O 3. Brunauer-Emmett-Teller analysis of various catalysts showed that the treated chars have a mesoporous structure, and the X-ray diffraction, X-ray fluorescence spectroscopy, scanning electron microscopy – energy dispersive spectroscopy showed that the presence of silica in the chars providing the stable support for the Ni loading and prevented coke formation. The chars obtained from biomass pretreatment could be a potential solution for preventing coke formation at high temperatures, thereby increasing the gas yield and enhancing hydrogen generation. • Rich husk derived biochar was applied to the catalytic gasification of food waste. • Ni/steam treated char showed maximum hydrogen generation (0.471 mol/(g feedstock.• g cat)). • Synergistic effect of added Ni and inherent K and Ca in char promoted H 2 formation. • The biochar as a support seems to be an economical solution for enhanced H 2 generation. [ABSTRACT FROM AUTHOR]

• A process of reducing 1,4-dioxane (DO) and producing H 2 simultaneously was assessed by a photocatalytic decomposition. • N-, Ni-codoped TiO 2 prepared by sol-gel reaction was employed as a visible light photocatalyst. • The photocatalyst codoped with N- and Ni ions showed the effect of greatly narrowing the bandgap. • Hydrogen was simultaneously generated with DO decomposition during the photocatalytic decomposition. • N-, Ni-codoped TiO 2 exhibited better photocatalytic decomposition and H 2 production than TiO 2. A process of reducing 1,4-dioxane (DO) and producing hydrogen simultaneously was attempted through a photocatalytic decomposition in aqueous DO solution, known as a carcinogen, using liquid phase plasma (LPP) and photocatalyst. N- and Ni- codoped TiO 2 (N-Ni-TiO 2) was prepared as a photocatalyst sensitive to visible light. The prepared N-Ni-TiO 2 absorbed the light extended to the visible light region compared to TiO 2. The bandgap of the photocatalyst was about 2.4 eV. The photocatalyst doped with Ni ions showed the effect of greatly narrowing the bandgap. During the photocatalytic decomposition of DO, hydrogen was generated simultaneously with DO decomposition. In this reaction, N-Ni-TiO 2 showed better DO decomposition and hydrogen production efficiency than TiO 2 by irradiation of LPP emitting strong UV and visible light. This is because N-Ni-TiO 2 can cause photocatalytic reaction in both UV and visible light. [ABSTRACT FROM AUTHOR]

• Ethanolamine was degraded by liquid phase plasma on perovskite photocatalysts. • Eu-doped SrAl 2 O 4 and CaTiO 3 perovskites were employed as photocatalysts. • Hydrogen was evolved with degradation of ethanolamine by photocatalytic splitting. • Hydrogen evolution was enhanced over the perovskite photocatalysts in the photocatalytic reaction. • The rate of hydrogen evolution in ethanolamine solution was higher than that in pure water. Liquid phase plasma process was applied in production of hydrogen and purification of wastewater. Ethanolamine released from a nuclear power plant was degraded by photocatalytic decomposition using the liquid phase plasma with perovskite photocatalysts. Eu-doped CaTiO 3 and Eu-doped SrAl 2 O 4 perovskites were compared with that of commercial TiO 2 photocatalyst. The photocatalytic decomposition of ethanolamine-contained water induced the degradation of ethanolamine and H 2 evolution, simultaneously. The degradation of ethanolamine and H 2 evolution were elevated on Eu-doped CaTiO 3 perovskite which having less bandgap energy. The rate of H 2 evolution in the ethanolamine-containing water was higher than that in pure water, which was attributed to the additional H 2 evolution by the photo-decomposition of ethanolamine in water. [ABSTRACT FROM AUTHOR]

• CO 2 offers a strategic means to maximize the carbon utilization and H 2 production. • CO 2 expedites kinetics of gas phase reaction between CO 2 and volatile pyrolysates. • Ni/SiO 2 catalytically enhances mechanistic roles of CO 2 in pyrolysis. • Exploiting CO 2 in catalytic pyrolysis could prevent coke formation. This study aimed to determine the synergistic effects of CO 2 on the catalytic pyrolysis of pine sawdust over a Ni-based catalyst (Ni/SiO 2) to establish a sustainable platform for H 2 production. To elucidate the reaction mechanism, the CO 2 -cofeeding pyrolysis of pine sawdust was performed. The CO 2 -cofeeding pyrolysis of pine sawdust proved that the gas-phase reaction between CO 2 and pyrolysates led to the increase in the amount of generated CO. The CO 2 enhanced thermal cracking and dehydrogenation. These mechanistic features of CO 2 were catalytically enhanced when Ni/SiO 2 was employed as heterogeneous catalyst, which led to an increase in the amounts of generated H 2 and CO. Hence, the CO that was additionally generated during the gas-phase reaction of CO 2 and pyrolysates could be further converted into H 2. In addition, CO 2 could be looped in the CO 2 -cofeeding pyrolysis of pine sawdust. Furthermore, exploiting CO 2 as raw material or reactive gas medium in the catalytic pyrolysis process also offered a strategic means for preventing coke formation. [ABSTRACT FROM AUTHOR]