Hydrogen Generation Reaction Research Articles

Hydrogen generation by coupling methanol steam reforming with metal hydride hydrolysis.

Methanol steam reforming (MSR) and hydrolysis of metal hydrides are two important hydrogen generation reactions with complementary characteristics. Coupling of the above two reactions leads to better hydrogen generation performance. The CO2 generated from MSR can be absorbed by the hydroxide generated from hydrolysis, leading to higher H2 purity. The hydrolysis heat can be utilized to drive the endothermic MSR reaction. By carrying out MSR on a CaH2-CuO composite, a hydrogen density of 6.56 wt% based on all the reactants with H2 purity higher than 99% can be obtained at 250 °C.

Facilitated charge transfer in ZnIn2S4@CuInP2S6 heterojunctions towards efficient photocatalytic H2 generation

Accelerating charge separation and migration in semiconductor photocatalysts is the key for acquiring high performance in the photocatalytic hydrogen generation reaction. In this work, a new ZnIn2S4/CuInP2S6 hetero-structured system (ZIS/CIPS) is designed and constructed. Owing to the presence of face-to-face hetero-interface with high charge-transport capability, the photocatalytic hydrogen generation rate of ZIS/CIPS dramatically enhanced (76.2 μmol h−1) under the visible-light irradiation, which is up to 13 and 190 times compared to that of ZnIn2S4 and CuInP2S6 (CIPS), respectively.

Application of oil in situ combustion for the catalytic methane conversion in the porous medium of the gas reservoir

Catalytic methane conversion (CMC) could be realized in situ in gas reservoirs. Through this process, a new environment-friendly energy carrier - hydrogen-can be generated inside the hydrocarbon field's porous medium. This method can become a new low-carbon, cost-effective method for hydrogen production. For this purpose, the catalyst has to be delivered into the reservoir, and the temperature inside the active zone of the reservoir has to be raised. The effective way to increase the temperature directly inside the reservoir is by injection of air and combustion of saturating liquid hydrocarbons. This research investigates the CMC process at conditions achieved in the reservoir due to oil in situ combustion (ISC). Numerical and physical modeling of in situ hydrogen generation from methane was performed using forward wet ISC of oil to heat the reservoir. The results of the unique experiment on a crushed oil-saturated core-packed model with different inlet flow rates of air, steam, and methane in the combustion tube (CT) are presented in the current study. The experiment consisted of four parts with different regimes and operational parameters: forward ISC of oil, steam methane reforming (SMR) at 450 °C and 8.9 MPa, SMR at 550 °C and 8.9 MPa, SMR at 550 °C and 2.3 MPa. The combination of these processes has led to the generation of hydrogen and methane conversion rates of up to 40% (during the combustion stage). Comparatively, low hydrogen yield was observed within the experiment, possibly due to the secondary reactions. However, irreversible reduction of oil viscosity, density, sulfur, and asphaltenes content was achieved within the experiment. The influence of catalyst and generated hydrogen on oil quality is one of the additional positive effects of in situ hydrogen generation. The numerical simulation of the experiment was performed for further study of the optimal hydrogen generation conditions. The proposed kinetic model consisted of ISC reactions and hydrogen generation reactions. The primary purpose of this experiment was to validate the principle study of the possibility of in situ hydrogen generation and simulate the processes in the core model physically and numerically.

By−products from the Al−water Reaction for Hydrogen Generation−Evolution and Properties

AbstractIn this paper, the properties and evolution during the calcination process of hydrolysis by−products from the reaction between Al−based composites and water for hydrogen generation were systematically investigated. The results showed that the main phases of by−products included AlOOH and InSn4. The amorphous product possessed a large Brunauer−Emmett−Teller (BET) surface area with 276.77 m2/g and high porosity properties with 0.37 cm3/g. The phase transformation of by−products from AlOOH to γ−Al2O3, δ−Al2O3, and α−Al2O3 occurred during the calcination process. It appears that the by−products can be used as raw materials for the preparation of Al2O3 with different crystal structures. Discussion on the properties and evolution of hydrolysis by−products are beneficial to product reuse and recovery. In this way, the cost reduction of hydrogen production via Al−water reaction can be realized, promoting the sustainable development of hydrogen production from Al−water reaction.

Ni(II)-Incorporated Porphyrin-Based Conjugated Porous Polymer Derived from 2,6-Diformyl-4-methylphenol as a Catalyst for the Urea Oxidation Reaction

The urea oxidation reaction (UOR) is an excellent alternative to the sluggish oxygen evolution reaction (OER) as an anode reaction for hydrogen generation via electrochemical water splitting. Here, a porphyrin-based conjugated porous polymer (CPP) has been developed through the polycondensation reaction of 2,6-diformyl-4-methylphenol and pyrrole (DMP-POR). The nickel(II) complex of this conjugated polymer Ni-DMP-POR shows efficient UOR in an alkaline medium. The as-synthesized materials were characterized by solid-state 13C CP-MAS, thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The porous property of the materials was characterized by N2 adsorption/desorption isotherms at 77 K. Both DMP-POR and Ni-DMP-POR showed excellent thermal stability. The Ni-DMP-POR exhibits very good UOR in 1 M KOH and 0.33 M urea with an overpotential of 260 mV at 10 mA cm-2 and a Tafel slope of 48 mV dec-1. The catalyst also shows excellent chronoamperometric and chronopotentiometric stability, suggesting its future scope in sustainable hydrogen production from wastewater resources.

Ni-Doped CuO Nanoarrays Activate Urea Adsorption and Stabilizes Reaction Intermediates to Achieve High-Performance Urea Oxidation Catalysts.

Urea oxidation reaction (UOR) with a low equilibrium potential offers a promising route to replace the oxygen evolution reaction for energy-saving hydrogen generation. However, the overpotential of the UOR is still high due to the complicated 6e- transfer process and adsorption/desorption of intermediate products. Herein, utilizing a cation exchange strategy, Ni-doped CuO nanoarrays grown on 3D Cu foam are synthesized. Notably, Ni-CuO NAs/CF requires a low potential of 1.366V versus a reversible hydrogen electrode to drive a current density of 100mA cm-2 , outperforming various benchmark electrocatalysts and maintaining robust stability in alkaline media. Theoretical and experimental studies reveal that Ni as the driving force center can effectively enhance the urea adsorption and stabilize CO*/NH* intermediates toward the UOR. These findings suggest a new direction for constructing nanostructures and modulating electronic structures, ultimately developing promising Cu-based electrode catalysts.

Ni2 Se3 -CuSex Heterostructure as a Highly Efficient Bifunctional Electrocatalyst for Urea-Assisted Hydrogen Generation.

Coupling urea oxidation reaction (UOR) with hydrogen evolution reaction (HER) is an attractive alternative anode reaction for electrochemical hydrogen generation with low energy consumption. However, the development of highly efficient bifunctional electrocatalysts is still a challenge. In this work, Ni2 Se3 -CuSex heterostructure was synthesized on copper foam (Ni3 Se2 @CuSex /CF) by electrodeposition accompanied by a selenization process. Benefiting from the abundant active sites, faster reaction kinetics, and modulated electronic structure, the self-supporting Ni3 Se2 @CuSex /CF electrode exhibited superior catalytic performance. Extremely low overpotentials of 120 and 140 mV were achieved at the current density of 100 mA cm-2 for HER/UOR, respectively. Respectively, in HER||UOR coupled electrolyzer for H2 generation, the Ni3 Se2 @CuSex /CF||Ni3 Se2 @CuSex /CF delivered a low cell voltage of 1.49 V to reach a high current density of 100 mA cm-2 along with good stability, outperforming most of the other well-developed materials to date. The rational design of coupled heterostructure as bifunctional electrodes is a promising approach for energy-saving H2 production.

Catalyze hydrolysis reaction for hydrogen generation by Mg/Mg2Ca nanolamellar structure in Mg–Ca alloys

The hydrogen generating characteristics of Mg–Ca alloys with Mg/Mg 2 Ca nanolamellar structures in the hydrolysis reaction with artificial seawater—a 3.5-wt% NaCl aqueous solution—were investigated for a new hydrogen supply source application. The concept of this study was to fabricate a complete hydrolysis reaction alloy using nanolamellar structure of Mg and Mg 2 Ca having an electrochemically less noble product than Mg. The hydrolysis reaction properties of Mg-10Ca, Mg-15Ca, Mg-16.2Ca, Mg-20Ca, and Mg 2 Ca were compared with respect to microstructure, which is the volume fraction of the primary phase and its nanolamellar width, and reaction temperatures at 10 °C, 20 °C, 30 °C, 40 °C, 50 °C, and 60 °C. Mg-16.2Ca and Mg-20Ca reacted completely even at room temperature and became white powders comprising Mg(OH) 2 , Ca(OH) 2 , and CaCO 3 after 9–14 days without changing the solvent. The hydrolysis reaction rates of the Mg–Ca alloys in the temperature range of 10–40 °C were fast in the order of Mg-16.2Ca ≥ Mg-20Ca ≥ Mg-10Ca ≥ Mg-15Ca. From the results of the hydrolysis reaction rate dependency on temperature, the activation energies of Mg-10Ca, Mg-15Ca, Mg-16.2Ca, Mg-20Ca, and Mg 2 Ca were estimated to be 41.27, 43.39, 22.07, 15.46, and 29.27 kJ mol −1 , respectively. This study revealed that the eutectic structure with several nanogalvanic cells of Mg/Mg 2 Ca in the alloys accelerated the hydrolysis reaction and completely reacted with artificial seawater for hydrogen generation.

Polyoxometalate-based nanostructures for electrocatalytic and photocatalytic CO 2 reduction

Electro/photocatalytic carbon dioxide (CO₂) reduction to value-added chemicals and fuels is being actively studied as a promising pathway for renewable energy storage and climate change mitigation. Because of inert molecular properties and competing hydrogen generation reactions, high-performance electrocatalysts with high Faradaic efficiency and product selectivity but low overpotential are urgently needed. Polyoxometalates (POMs) are a class of polynuclear metal oxide clusters with a precise atomic structure, providing an ideal research platform to reveal the relationship between macroscopic properties and microstructures. Moreover, their highly tunable redox properties and abundant transition metal atom composition ensure thriving research for POM-based nanostructures toward CO₂ reduction. In this review, we first introduce the specific roles of POMs in electro/photocatalytic CO₂ reduction. Recent advances in POM-based nanostructures ranging from single clusters, assemblies, organic–inorganic hybrids to derivatives are systematically summarized. In particular, the structure–performance relationship of POM-based nanostructures is discussed at the atomic and molecular levels. Finally, the challenges and opportunities in the design of high-efficiency POM-based nanostructures are discussed to promote electro/photocatalytic CO₂ reduction.

A novel Dy3+ modified Zn2Ti3O8 nanoparticles for efficient hydrogen production photocatalysis

Novel Dy 3+ :Zn 2 Ti 3 O 8 (Dy 3+ :ZTO) nano-photocatalysts with different Dy 3+ concentrations were applied to enhance the photocatalytic hydrogen generation activity from sodium borohydride hydrolysis reaction. XRD and Raman measurements confirm the formation of cubic Zn 2 Ti 3 O 8 phase as a major phase in addition to minor TiO 2 phase. The analysis of XPS spectra shows the existence of lattice oxygen (LO) and non-lattice oxygen (NLO) where 0.07 mol Dy 3+ :ZTO has the highest percentage of NLO compared to the undoped photocatalyst. The energy gap value decreases with increasing doping concentrations (3.137 eV for 0.07 mol Dy 3+ :ZTO). The degree of disorder, represented by Urbach energy, has an optimum high value (0.169 eV) for 0.07 mol Dy 3+: ZTO. The photoluminescence studies revealed that Dy 3+ dopant can effectively separate the photogenerated electron/hole pairs in the ZTO. These photocatalysts have strong photocatalytic hydrogen generation. The most active nano-photocatalyst towards hydrogen generation was 0.07 mol Dy 3+ : ZTO (5.6 mmol/g). The highest photocatalytic activity for 0.07 mol Dy 3+ : ZTO are attributed to the lower recombination rate associated with the higher disorder and oxygen vacancies relative to the undoped photocatalyst. The stability and reusability of the most active photocatalyst were investigated. The results confirm that the developed photocatalyst has good durability in hydrogen generation reaction. The results, moreover, revealed that Dy 3+ : ZTO nano-photocatalyst is a promising nanomaterial in the field of energy production. Graphical illustration for the hydrogen generation. • Novel Dy 3+ :Zn 2 Ti 3 O 8 (Dy 3+ :ZTO) nano-photocatalysts were prepared. • Dy 3+ dopant can effectively separate the photogenerated carriers in the ZTO. • Dy 3+ :ZTO enhances the photocatalytic activity of hydrogen generation. • Catalyst reusability and stability of 0.07 mol Dy 3+ :ZTO was tested.

A review on biomass-derived N-doped carbons as electrocatalysts in electrochemical energy applications

The development of biomass-derived N-doped carbonaceous materials as electrocatalysts is of great importance considering their resource abundance in the earth, low price, ease synthesis process, and their electro/chemical compatibility as reaction medium for a wide range of electrochemical energy applications. In the current review, various types of biomass-derived N-doped carbon materials with the combination of heteroatoms (H), transition metals, and conducting polymers are reviewed according to their roles in each application that includes fuel cells, water splitting, batteries, and supercapacitors. The electrocatalytic activity of biomass-derived N-doped carbon materials is discussed based on the key reactions of each application, such as oxygen redox reaction, hydrogen generation reaction, sulfur/vanadium redox reactions and so on. For example, oxygen reduction reaction electrocatalysts can be categorized into five types, that is, i) metal-free N doping, ii) metal-free N, H co-doping, iii) metal-free N, H multiple doping, iv) metal-N doping, and v) metal-N, H co-doping. Further, their electrochemical performance is compared with state-of-the-art noble metal-based catalysts including Pt/C and IrO2. The key roles of the biomass-derived N-doped carbonaceous electrocatalysts in various types of rechargeable batteries, meanwhile, are first summarized including metal-air, lithium-sulfur, metal–carbon dioxide, and vanadium redox flow batteries. It is anticipated that this review could not only contribute to the rational design of biomass-derived catalyst synthesis but also boost scientific research efforts in the valorization of biomass-derived resources for the electrochemical energy applications.

Two-dimensional ZnO/BlueP van der Waals heterostructure used for visible-light driven water splitting: A first-principles study

Solar driven water splitting for hydrogen generation has been considered as an important method for collecting clean energy. Herein, based on first-principles calculations, we propose that ZnO/BlueP van der Waals heterostructure can realize overall water splitting reaction for hydrogen generation. Strikingly, the band-gap of 1.83 eV is appropriate, and band alignments straddle the water redox potentials, ensuring the occurrence of hydrogenevolutionreaction and oxygen evolution reaction. Charge density distribution and carrier mobility exhibit significant charge separation and transfer. Visible-light response is improved compared with those of the isolated monolayers. Moreover, hydrogenevolutionreaction is actually realized on the ZnO layer, while oxygen evolution reaction is implemented on the BlueP layer. Through the investigation of the adsorption and dissociation reactions of H2O, we observe that two neighboring H*s prefer to combine to form H2 by overcoming a lowered energy barrier of 0.75 eV. Strain effect indicates that the lateral compressive strain of −4% to 0% and the vertical tensile strain of 0% to +6% can effectively tune band-gap and band alignments. The results indicate that ZnO/BlueP vdW heterostructure is probable highly efficient photoelectric material used for visible-light driven water splitting for hydrogen generation.

Fabricating WS2/Mn0.5Cd0.5S/CuInS2 hierarchical tandem p-n heterojunction for highly efficient hydrogen production

Effective charge separation and sufficient light harvesting are crucial for photocatalytic water splitting into renewable and storable hydrogen energy. Employing WS2 as cocatalyst and CuInS2 as p-type semiconductor and photosensitizer, a novel WS2/Mn0.5Cd0.5S/CuInS2 hierarchical tandem p-n heterostructure was constructed based on the energy band engineering theory. In this tandem p-n heterostructure, Mn0.5Cd0.5S nanoparticles adhere closely to CuInS2 nanosheets to form a p-n junction along with the strong and monodirectional inner-built electric field, which can regulate the directional transfer/migration of photoinduced electrons-hole pairs and significantly boost the charge separation. Furthermore, the WS2 cocatalyst employed in the ternary heterostructure further expedites the spatial charge separation and directional migration of photoexcited electrons, as well as simultaneously provides plentiful reaction active sites to decrease the activation barrier for hydrogen generation reaction. Benefiting from the synergetic cooperation of WS2 cocatalyst and the p-n junction charge transfer channels, the smartly designed ternary WS2/Mn0.5Cd0.5S/CuInS2 heterostructure displays the optimal photoactivity toward hydrogen production (681.7 μmol h−1), more 3.98-fold enhancement than individual Mn0.5Cd0.5S under simulated sunlight irradiation. This research provides a new avenue for constructing multi-hierarchical systems with remarkably boosted charge separation and light-harvesting abilities for high-efficiency solar energy conversion.

Superior efficiency of BN/Ce2O3/TiO2 nanofibers for photocatalytic hydrogen generation reactions

One-dimensional BN/Ce2O3/TiO2 heteroarchitectures with high visible-light photocatalytic activity have been successfully obtained by an electrospinning technique. The properties of the prepared nanofibers were controlled using different ratios of cerium. The results of XPS characterization revealed that the Ce element is present in the valence state + III on the surface of the TiO2 nanofibers. Rietveld refinement of XRD data reveals that introducing small concentrations of Ce3+ (<3.0 at%) into the electrospinning solution leads to the formation of small amounts of rutile and brookite phases, a decrease in the crystallite size of the main anatase phase and a slight decrease in the c parameter and unit cell volume of the anatase phase. In contrast, only the anatase phase, which has a similar crystallite size and lattice parameters to that formed in the undoped sample, is observed when 3 at.% Ce is used. These results suggest that Ce3+ ions did not substitute Ti4+ ions in the lattice of both anatase and rutile phases, which can be explained by the large difference in the ionic radius of Ti4+ and Ce3+ ((r (Ti4+) = 60.5 pm, r (Ce3+) = 101.7 pm). Scanning electron microscopy demonstrates that the diameter of the obtained nanofibers decreases from 240 nm for pristine TiO2 to 101 nm, 70 nm, 40 nm for 2% Ce/TiO2 (CET2), BN/TiO2 (BT) and BN/2% Ce/TiO2 (BCET2), respectively. The d-spacing decreased by 0.3 nm after Ce incorporation as demonstrated by high-resolution transmission electron microscopy. XPS proved the presence of BN nanosheets along with Ce2O3 and TiO2 into the nanofibers. Compared with the pure TiO2 nanofibers (NF), the obtained Ce/Ti ratio of 2% (molar ratio) showed an enhancement of the visible-light photocatalytic activity to water splitting, which is 46 times higher than that of bare TiO2 NF. The Ce2O3 might improve the separation of photogenerated electrons and holes derived from the coupling effect of TiO2 and cerium oxide. This work also examines the modification of TiO2 (anatase) properties with hexagonal boron nitride (h-BN) and the impact this coupling has on photocatalytic activity. XPS proved the presence of BN nanosheets along with Ce2O3 and TiO2 into the nanofibers. The electron transfer rate was improved by BN exfoliation. The photocatalytic results indicated that the BN/Ce2O3/TiO2 nanofibers improve hydrogen production up to 5100 μmol/g for 6 h under visible light, which could be due to the presence of BN sheets that enhanced the separation of the photo-induced electron–hole pairs in TiO2 and increased the specific surface area compared to pure TiO2 and Ce2O3/TiO2 nanofibers. Moreover, the BN/Ce2O3/TiO2 could be easily recycled without decrease in the photocatalytic activity because of its one-dimensional nanostructure nature. Moreover, the present work focuses on the ternary composite of BN/Ce2O3/TiO2 for optimization of electronic and phonon transport properties using the state-of-the-art density functional theory (DFT). The calculated electronic density of states (DOS) modulus shows an excellent agreement compared with available theoretical and experimental data for hydrogen production.

Rhodium(0) nano particles within an organic cage with better durability and gated activity for hydrogen generation reaction

Stable and catalytically active nano particles with small sizes are of paramount importance in catalysis, but the preparation of such particles has been a great challenge due to their propensity to aggregate into large and less active particles. Herein, we would like to report the formation of ultra-small and uncommon RhO2 particles within an organic cage in the homogeneous solution, and the soluble assembly showed both better durability and high activity towards ammonia borane methanolysis to generate hydrogen gas. A volcanic plot of the turnover frequencies (TOFs) over the molar amount of Rh per cage was demonstrated, and RhO2-30@COP1-T showed a TOF of around 286 min−1 at room temperature. Our assembly also showed better durability during the catalysis in contrast to NPs made from pure rhodium acetate, and there was no aggregation formed after five runs. We further demonstrated the Michaelis-Menten model through the kinetic study, an indication that the catalytic reaction happened within the organic cage. The actual active sites of the catalyst was zero-valent metal Rh. Interestingly the installation of azobenzene groups at the opening of the cage led to gated activity through the trans-cis conformation interchange, due to the different steric hindrances affecting the diffusion rates of reactants.

Amorphization of Metal Nanoparticles by 2D Twisted Polymer for Super Hydrogen Evolution Reaction (Adv. Energy Mater. 16/2022)

Hydrogen Evolution Reaction In article number 2102257 Hyoyoung Lee and co-workers report a novel strategy to synthesize amorphous metal nanoparticles with the help of a twisted covalent organic network. The prepared amorphous Ru nanocluster shows higher hydrogen generation reaction mass activity than commercial Pt/C with superior stability in alkaline conditions.

A novel hierarchical CdS-DETA@CoP composite as highly stable photocatalyst for efficient H2 evolution from water splitting under visible light irradiation

The photolysis of water using photocatalysts under sunlight irradiation for hydrogen generation reaction is an efficient strategy to solve energy and environmental issues. Herein, a novel hierarchical CdS-DETA@CoP composite was fabricated and applied to visible-light-driven photocatalytic water splitting for generating H2. To achieve this goal, we first prepared a 3D hierarchical CoP co-catalyst via direct phosphatization of the ZIF-67 precursor. Then, two-dimensional (2D) CdS-DETA nanosheets were in situ grown on the surface of hierarchical CoP through a facile water bath method, obtaining a CdS-DETA@CoP composite with a high surface area. The CdS-DETA@CoP composite with 20 wt% CoP exhibits a maximum photocatalytic H2 evolution rate of 48.76 mmol g–1h−1 under visible light irradiation with lactic acid as the sacrificial reagent, which is 46.4 times as high as CdS-DETA. The synergistic effect between CdS-DETA and CoP induced remarkable ability of light-harvesting and efficient separation of photogenerated electron-hole pairs, thus profoundly promoting the activity and stability. The excellent activity is also closely related to the better dispersion of CdS-DETA on the surface of hierarchical CoP co-catalyst.

Effect of Au Plasmonic Material on Poly M-Toluidine for Photoelectrochemical Hydrogen Generation from Sewage Water.

This study provides H2 gas as a renewable energy source from sewage water splitting reaction using a PMT/Au photocathode. So, this study has a dual benefit for hydrogen generation; at the same time, it removes the contaminations of sewage water. The preparation of the PMT is carried out through the polymerization process from an acid medium. Then, the Au sputter was carried out using the sputter device under different times (1 and 2 min) for PMT/Au-1 min and PMT/Au-2min, respectively. The complete analyses confirm the chemical structure, such as XRD, FTIR, HNMR, SEM, and Vis-UV optical analyses. The prepared electrode PMT/Au is used for the hydrogen generation reaction using Na2S2O3 or sewage water as an electrolyte. The PMT crystalline size is 15 nm. The incident photon to current efficiency (IPCE) efficiency increases from 2.3 to 3.6% (at 390 nm), and the number of H2 moles increases from 8.4 to 33.1 mmol h−1 cm−2 for using Na2S2O3 and sewage water as electrolyte, respectively. Moreover, all the thermodynamic parameters, such as activation energy (Ea), enthalpy (ΔH*), and entropy (ΔS*), were calculated; additionally, a simple mechanism is mentioned for the water-splitting reaction.

Hybrid Plasmonic Nanomaterials for Hydrogen Generation and Carbon Dioxide Reduction.

The successful development of artificial photosynthesis requires finding new materials able to efficiently harvest sunlight and catalyze hydrogen generation and carbon dioxide reduction reactions. Plasmonic nanoparticles are promising candidates for these tasks, due to their ability to confine solar energy into molecular regions. Here, we review recent developments in hybrid plasmonic photocatalysis, including the combination of plasmonic nanomaterials with catalytic metals, semiconductors, perovskites, 2D materials, metal–organic frameworks, and electrochemical cells. We perform a quantitative comparison of the demonstrated activity and selectivity of these materials for solar fuel generation in the liquid phase. In this way, we critically assess the state-of-the-art of hybrid plasmonic photocatalysts for solar fuel production, allowing its benchmarking against other existing heterogeneous catalysts. Our analysis allows the identification of the best performing plasmonic systems, useful to design a new generation of plasmonic catalysts.

Enhanced hydrogen generation by reverse spillover effects over bicomponent catalysts

The contribution of the reverse spillover effect to hydrogen generation reactions is still controversial. Herein, the promotion functions for reverse spillover in the ammonia borane hydrolysis reaction are proven by constructing a spatially separated NiO/Al2O3/Pt bicomponent catalyst via atomic layer deposition and performing in situ quick X-ray absorption near-edge structure (XANES) characterization. For the NiO/Al2O3/Pt catalyst, NiO and Pt nanoparticles are attached to the outer and inner surfaces of Al2O3 nanotubes, respectively. In situ XANES results reveal that for ammonia borane hydrolysis, the H species generated at NiO sites spill across the support to the Pt sites reversely. The reverse spillover effects account for enhanced H2 generation rates for NiO/Al2O3/Pt. For the CoOx/Al2O3/Pt and NiO/TiO2/Pt catalysts, reverse spillover effects are also confirmed. We believe that an in-depth understanding of the reverse effects will be helpful to clarify the catalytic mechanisms and provide a guide for designing highly efficient catalysts for hydrogen generation reactions.