Facing the current energy crisis, developing new green energy and advancing high-quality energy development are crucial, as multimetal sulfide semiconductors have great potential in photoenergy conversion. This study prepared a carbon-containing bimetallic phosphide (NiCoP@C) cocatalyst from a CoNi-based MOF, which was combined with ZnIn2S4 (ZIS) hollow nanoflowers to enhance electrical conductivity and photocatalytic hydrogen production of the composite. XPS shows electron cloud density of ZIS increases in the composite via interfacial electronic reconstruction. FESEM reveals NiCoP@C nanoparticles are evenly anchored on surface and interlayer gaps of ZIS, forming a hierarchical heterostructure with more active sites. Performance tests show Z-NiCoP@C has a photocurrent density of 129.58 mu A cm- 2 (vs. 34 mu A cm- 2 of unmodified ZIS). Under 10 W visible light with 10% TEOA as a sacrificial agent, 10-h cumulative H2 yield of the composite is 19.52 mmol g- 1, with a H2 evolution rate of 1.95 mmol g- 1 h- 1, 7.8-fold that of pristine ZIS (0.25 mmol g- 1 h- 1).

Enhancing the migration of photogenerated charges in semiconductor catalysts is an important way to enhance hydrogen (H2) production. We fabricated ZnIn2S4-CuNiP (Z-CuNiP) heterostructure by a simple ultrasonic blending method. These composites can be thought of as cheaper substitutes for expensive metal cocatalysts such as platinum or palladium. The incorporation of CuNiP was found to be highly efficacious in increasing the photocatalytic performance of ZnIn2S4 (ZIS) in visible light of relatively low intensity to reach a H2 production rate of 1.06 mmol·g-1·h-1. This is roughly four times that of pure ZIS. A key characteristic is the occurrence of a wide and close contact between ZIS and CuNiP that allows separation of photoinduced electron-hole pairs. Due to this, the efficiency of photocatalytic water splitting with respect to ZIS of the designed heterostructure increases significantly.

Incorporating hydrogen into transition metal oxides with intricate structures offers significant potential for discovering exotic phenomena and functionalities by facilitating interactions between hydrogen ions and structural phases. Mixed-phase (M-C + R '/T ' phases) BiFeO3(BFO) has attracted considerable attention due to its numerous physical property discoveries, making it a promising candidate for modulation through hydrogen insertion. This study systematically investigates the structural evolution of BFO films under three distinct hydrogen injection methods: noble metal-catalyzed injection, ionic liquid gating, and hydrogen reduction. Comprehensive XRD analysis reveals that varying proton pathways and injection intensities induce characteristic structural modifications. X-ray absorption spectroscopy and x-ray photon spectroscopy results provide a more in-depth examination of the variations in valence states and oxygen ions migration induced by protonation in BFO films. Furthermore, the magnetism of the mixed-phase BFO increases, and the spontaneous polarization domains are enhanced, during the migration of protons and oxygen ions. This work provides valuable insights into hydrogen-associated electronic phase transitions within the mixed-phase BFO, advancing its potential applications in next-generation electronic devices.

The photoelectrochemical water-splitting process for hydrogen production is limited by the large bandgap of semiconductor titanium dioxide (TiO2) and by interfacial recombination at particle interfaces. The technique used in this paper is that of electrochemical anodization to produce robust, ordered TiO2 nanotube arrays (TiO2 nanorod arrays denoted as TNTAs). Using the immersion-annealing method, Nd2O3 nanoparticles can be immobilized in situ, and Nd2O3/TNTAs composite photoanodes are fabricated. The heterointerface caused between the Nd2O3 nanoparticles and TiO2 results in the alignment of the Fermi levels and the formation of band bending and an internal electric field at the interface. It allows rapid photo-generated electron-hole (e(-)/h(+)) separation at the interface and, simultaneously, introduces novel localized electron states of Nd3+ within the TiO2 bandgap. This triggers hybridisation between the 3d orbitals of Ti and the 2p orbitals of O, thereby altering the band structure of TiO2. The best-performing Nd2O3/TNTAs photoelectrode outperforms pure TNTAs, with a photocurrent density of 1.59 mA & centerdot;cm(-2) at 1.23 V vs. RHE. It produces 162.6 mu mol & centerdot;cm(-2) of hydrogen in a 3 h photocatalytic hydrogen production experiment, which is about 12.2 times that of pure TNTAs. This approach highlights the unique benefits and creative opportunities of applying rare-earth elements to address the critical issues of photocatalysts, such as significant band gaps and rapid recombination.

Photoelectrochemical water splitting is considered one of the key pathways for efficiently converting solar energy into hydrogen energy. This study employed electrochemical anodization to fabricate ordered TiO2 nanotube arrays (TNTAs), followed by in situ loading of Ho2O3 nanoparticles onto their surfaces via impregnation-annealing, forming Ho2O3/TNTAs nanocomposite photoanodes. The 4f state of Ho3+ introduces localized energy levels within the TiO2 band gap. It hybridizes with Ti 3d and O 2p orbitals, thereby achieving bandgap tuning, promoting rapid migration of photogenerated electrons at the heterojunction interface, and suppressing e–/h+ recombination. The optimized Ho2O3/TNTAs photoanode achieves a photocurrent density of 1.73 mA/cm2, significantly higher than that of pure TNTAs. During a 3-hour photocatalytic hydrogen production experiment under constant bias, the cumulative hydrogen yield of Ho2O3/TNTAs reaches 61.37 μmol/(cm2·h), approximately 6.19 times that of TNTAs. In summary, Ho2O3-modified TiO2 nanotube arrays demonstrate outstanding photocatalytic conversion and hydrogen evolution performance in photocatalytic water splitting for hydrogen production, providing a viable strategy for constructing efficient Photoelectrochemical (PEC) photoanodes based on rare-earth oxide-modified TiO2.

ABSTRACT The strategic incorporation of open‐shell radicals into covalent organic frameworks (COFs) represents a promising yet underexplored avenue for designing metal‐free oxygen reduction reaction (ORR) electrocatalysts. Moving beyond conventional closed‐shell linker engineering, we present a one‐step multivariate synthesis to precisely install 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) radicals within a crystalline COF skeleton. The resulting radical‐embedded TPET‐TEMPO COF exhibits superior four‐electron (4e − ) ORR activity, evidenced by an electron transfer number of 3.95 and a minimal H 2 O 2 yield of 8.8% (at 0.25 V vs. RHE), considerably outperforming the radical‐free TPET analogue. Mechanistic studies using density functional theory (DFT) calculations attribute this performance to the TEMPO radicals functioning as an intrinsic electron shuttle, which lowers the activation barriers for ORR, in agreement with experimental observations. Practical viability of TPET‐TEMPO is demonstrated in a rechargeable zinc‐air battery (ZAB), where TPET‐TEMPO as the cathode catalyst delivers a peak power density of 148.4 mW cm −2 . This work highlights the critical role of radical motifs as active vertices and outlines a facile blueprint for constructing radical‐bearing COFs for efficient energy applications.

Thermo-photocatalytic CO2 conversion to C2 products exhibits high research value and industrial potential. Enhancing the catalyst's adsorption activation for CO2 and H2O, along with multistep proton-coupled electron transfer (PCET) and C-C coupling, is crucial for achieving thermo-photocatalytic CO2 reduction conversion to C2 products with H2O as a proton source in a continuous process. In this paper, we explore a novel approach utilizing biochar to obtain catalysts with more defects and combine reducing biochar with MOF Materials (ZIF-67) to get a composite (ZIF-67/PC) with substantial CO2 and H2O adsorption activation capabilities and electron density gradients. Compared to PC and ZIF-67, the ZIF-67/PC exhibited excellent catalytic performance, particularly in obtaining a certain amount of C2 products (yield 5.59 }mol g-1 h-1 , selectivity 55.96%). We also investigated the structure-function relationship of the catalyst and the contributions of thermal and light effects to the catalytic reaction, aiming to guide the establishment of efficient, high-throughput catalytic CO2 conversion technologies. (c) 2026 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Transition metal carbides/nitrides (MXenes) exhibit exceptional metallic conductivity and precisely tunable interlayer spacing, serving as promising candidates for overcoming key bottlenecks in next-generation energy storage devices. The performance of these devices remains constrained by several interconnected challenges. Inefficient ion transport arising from tortuous pathways, size mismatch, and polarization impede reaction kinetics. Structural degradation caused by electrode expansion and active material dissolution further reduce performance. Furthermore, interface issues such as corrosion, dendrite growth, and high impedance also severely limit efficiency. In this review, we summarize strategies for constructing composites with dimensional materials from zero-dimension (0D) to three-dimensions (3D). Emphasis is placed on synergistic enhancement mechanisms. We further evaluate the role of MXenes in addressing interfacial challenges like ion deposition, shuttle effect, solid-electrolyte interphase (SEI) formation, and contact resistance. Building on these insights, we discuss solutions for the practical application of MXene-based energy storage devices. This Review summarizes strategies for constructing composites based on MXenes for addressing challenges MXenes face in energy storage applications, such as ion deposition, shuttle effect, solid-electrolyte interphase formation, and contact resistance.

The heterogeneous interface region serves as a critical domain in lithium metal batteries, where electrons, ions, and chemical reactions interact, significantly affecting cycling reversibility. However, the ion transport mechanism of the solid electrolyte interphase (SEI) still lacks quantitative characterization. Using Li metal mixed inorganic compounds as a model system, we correlate and quantify the Li+ exchange rates of key SEI inorganic components by applying the saturation-recovery method and establishing a two-site chemical exchange model. We not only quantitatively reveal the interfacial ion exchange rate between lithium metal and its SEI via a selective nuclear magnetic resonance exchange spectroscopy (EXSY NMR) technique but also demonstrate a close connection between interfacial transport and lithium deposition morphology by a COMSOL simulation. Furthermore, through multiscale characterization including cross-polarization (CP) NMR and cryoelectron microscopy (cryo-EM), we elucidate the Li+ transport mechanisms within the actual SEI: Li2O can facilitate rapid Li+ transport, whereas the Li+ transport of LiF is highly dependent on building an interface with Li2O. On the basis of these new kinetic insights, we construct a Li2S artificial SEI using atomic layer deposition (ALD), successfully achieving 99.5% Coulombic efficiency and promoting uniform and dense lithium deposition. Our findings provide valuable design principles for engineering efficient SEIs in future lithium metal batteries.

Per- and polyfluoroalkyl substances (PFAS), as a class of persistent organic pollutants, are characterized by strong environmental persistence and high bioaccumulation potential, making them a major concern in global environmental and health fields. Currently, the trace detection of PFASs in urban environmental water samples, including surface water, source water, and domestic wastewater faces challenges such as insufficient adsorption selectivity of traditional materials and cumbersome pretreatment steps, highlighting the urgent need to develop efficient enrichment and highly sensitive analytical methods. To improve the enrichment efficiency of PFAS, this study designed and synthesized an amino-functionalized magnetic covalent organic framework material (NH₂-MCOF) as an adsorbent. Combined with magnetic solid-phase extraction (MSPE) and liquid chromatography-tandem mass spectrometry, a synchronous analytical method was established for the determination of 17 PFASs in real urban environmental water matrices. Through systematic optimization, the optimal pretreatment conditions were determined as follows: adsorbent dosage of 20 mg, solution pH of 3.0, ultrasonic-assisted adsorption time of 40 min, and a stepwise elution strategy using methanol, ammoniated methanol, and formic acid-modified methanol. Under the optimized conditions, the method demonstrated good linearity within the range of 0.5–200 μg/L, with detection limits of 0.0346–1.30 ng/L. The spiked recoveries ranged from 50% to 138%, and the intra-day and inter-day precision, expressed as relative standard deviations (RSD), were below 13.5% and 14.9%, respectively. Application to real water samples confirmed the method's effectiveness in detecting multiple PFASs, demonstrating its practicality and reliability. The analytical method established in this study integrates functionalized material design, efficient pretreatment, and sensitive detection, providing a reliable approach for the synchronous monitoring of multiple trace PFAS in real urban environmental water matrices and highlighting the potential application of functionalized magnetic covalent organic framework materials in environmental analysis.

Thin film is the form of material that most closely resembles the silicon-based integrated circuits (IC) and therefore has attracted tremendous attention over the past decades due to its potential applications in integrating functional devices on IC chips. The structural characterization of thin films, especially epitaxial film with complex structure has been a long-term challenge until the emergence of synchrotron three-dimensional diffraction technique (3D-RSM). 3D-RSM is a technique that can effectively collect various structural information of epitaxial films, such as crystal lattice, strain, domain variants, and oxygen octahedral rotation. Now, interpreting the massive experimental data of 3D-RSM becomes the biggest obstacle that is confronted by the researchers. In this work, we proposed a strategy that utilizes simulated 3D-RSM diffraction patterns as aid of data analysis. With this approach, the one-to-one correspondence between diffraction spots and domain variants, as well as the quantitative lattice constants and crystal system have been identified in sequence for two typical cases, either epitaxial PbTiO3/SmScO3(001) film or (CoCrFeMnNi)3O4 alloy film epitaxially grown on LaAlO3(001) substrate. Further, systematic simulations of 3D-RSM patterns for epitaxial films belonging to every of the seven crystalline symmetries were performed and exhibited, assuming the films are grown on a (001)-oriented cubic substrate. This work sheds light on more effective data analysis of 3D-RSM, i.e., more effective structural characterization of complex epitaxial films.

Iron and nitrogen-doped carbon (Fe-N/C) catalysts have been demonstrated to be effective in facilitating oxygen reduction reactions, making them a promising substitute for noble metal catalysts. Various factors, including the availability of transport channels and active sites, influence the performance of Fe-N/C. A Fe, N-doped porous carbon (Fe/NPC) catalyst with a three-dimensional structure was synthesized by modifying the precursor's morphology, composed of one-dimensional bamboo-like carbon nanotubes interwoven with two-dimensional graphitic carbon nanosheets. The high surface area of the nanosheets furnishes abundant active sites, while the nanotubes suppress sheet restacking and facilitate rapid charge/mass transport. Moreover, the synergistic interplay between Fe3C and Fe-N x sites imparts oxygen-reduction activity on par with Pt/C, underscoring its promise as a viable alternative. The Fe/NPC loading of 0.1 mg cm-2 showed a half-wave potential of 0.858 V. The current decay was only 7.6% after a 40,000 s constant voltage test. Upon integration of the catalyst into a zinc-air battery, the resulting cell demonstrated a noteworthy peak power density of 166.2 mW cm-2 and an impressive energy density of 952.7 Wh kg-1 Zn.

Electrochemical CO2 conversion into sustainable fuels and high-value chemicals represents a promising technology for producing valuable chemical products. However, the hydrogen evolution reaction (HER) becomes a major competing process during CO2 reduction reactions (CO2RR), posing significant challenges for catalyst design. In this study, Cu2O catalysts were synthesized via a simple one-pot hydrothermal method. The modification strategy of element doping was selected to design the catalyst. The Indium doping content was controlled through Cu/In ratio adjustment to modulate the selectivity of CO2 electrocatalytic reduction. Compared to Infree Cu2O, the Cu60In1 catalyst with an optimized Cu/In ratio exhibited enhanced CO2RR performance. At a low applied potential of -0.75 V vs. RHE, the catalyst demonstrated a current density of -29.2 mA & sdot;cm-2 with 80.3 % CO selectivity, representing an approximately 10-fold enhancement over pure Cu2O. In-situ IR analysis and DFT calculations demonstrate that In-doped Cu2O exposes (111) crystal facets more prone to *COOH formation. This intermediate generates *CO, promoting CO desorption while suppressing the hydrogen evolution reaction (HER), enhancing both catalytic activity and CO selectivity in CO2 reduction.

This study constructed a novel porous ion transport layer (BNX) to effectively regulate the electrode surface microenvironment, promoting ethylene generation during the electrochemical reduction of carbon dioxide (E-CO2RR) process. BNX, composed of hexagonal boron nitride nanosheets and basic anionic polymers, enriches K+ and OH-on the electrode surface, creating an alkaline and alkali-metal-rich reaction microenvironment. Experimental results show that the Cu(111) electrode with BNX introduced exhibited higher Faradaic efficiency and yield for ethylene (C2H4) in E-CO2RR while significantly suppressing the hydrogen evolution reaction (HER). In-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), and density functional theory (DFT) calculations revealed the influence of BNX on the adsorption behavior of reaction intermediates and the promotional effect of K+ and OH-on the hydrogenation of *CO and the coupling reaction of *COH with *CO. This study provides a general strategy for optimizing E-CO2RR by modulating the chemical microenvironment on the electrode surface.

TiO2 is a well-known photocatalyst due to its excellent photocatalytic activity, low cost, and stability. However, its practical applications are limited by its poor charge transport and wide bandgap. In this study, F-doped TiO2 nanorod arrays were synthesized using a simple chemical bath annealing method, which resulted in significantly improved properties. Among the samples, 0.05F-T(F-doped TiO2 nanorods) exhibited the best performance, with a photocurrent of 7.34 mA/cm2 at 1.8 V vs. reversible hydrogen electrode (RHE), which is 4.61 times higher than that of pure TiO2 nanorods (1.59 mA/cm2). Incident photon-to-current efficiency measurements showed prominent photocurrent responses in the 325-375 nm range and a slight redshift toward the visible region around 425 nm, indicating improved light absorption. The electron-hole separation efficiency was enhanced, and bandgap and flat-band potential measurements confirmed the optimization of the energy band structure. The photoelectrochemical performance for water splitting was also evaluated, with 0.05F-T achieving the highest hydrogen production of 842.28 µmol/cm2 in 5 h at 1.8 V vs. RHE, which is 6.58 times higher than that of pure TiO2 (128.05 µmol/cm2). These results demonstrate that F-doped TiO2 nanorods are promising for enhancing photocatalytic hydrogen production. Highlights 1. A simple wet chemical soaking method introduces the Fluoride (F) element into the TiO2 lattice. 2. F element doping changes the lattice spacing of TiO2 and optimizes the band structure. 3. The doping of the F element causes a red shift in the wavelength of TiO2 light absorption. 4. Efficient photoelectrochemical water splitting achieved by F-doped TiO2 nanorods.

Accelerating carrier transfer and increasing active surface sites are key to boosting hydrogen production in composite photocatalysts. This study introduces a novel phosphorus-modified MOF-derived cobalt/carbon cocatalyst, CoPC, as a viable alternative to noble metals like platinum and palladium. CoPC significantly enhances the photocatalytic performance of ZnIn2S4 (ZIS) under low-power visible light, achieving a hydrogen production rate of 2.1 mmol g- 1 h- 1, over seven times that of pure ZnIn2S4. CoPC's metallic properties improve charge carrier separation efficiency and offer additional active sites, boosting the photocatalytic water-splitting efficiency of the ZnIn2S4-CoPC system.

Electrocatalysis plays an essential role in sustainable energy conversion technologies such as fuel cells, water electrolysis, and the carbon dioxide reduction reaction that occurs at solid–liquid interfaces. However, due to the complexity of the respective electrochemical interfaces and trace amounts of interfacial species, researchers’ knowledge of these reaction mechanisms remains incomplete, limiting our ability to improve electrocatalytic performance. In situ electrochemical surface-enhanced Raman spectroscopy (EC-SERS) has proven to have appealing potential for the study of electrocatalytic reaction mechanisms because it can provide exceptionally sensitive fingerprint vibrational spectroscopic information about interfacial species and their interactions. This review offers insights into electrocatalysis through in situ EC-SERS. We begin with an introduction to the basic principles, substrate engineering, and the implementation of in situ EC-SERS for electrocatalysis, with an emphasis on capturing trace interfacial species and determining the capability of this technique. We then discuss fundamentals, still-debated mechanistic issues, as well as advanced applications of EC-SERS for mechanism studies of the fundamentally and practically important reactions in sustainable energy conversion technologies, to gain insights into electrocatalysis. Finally, we propose directions for the future development of in situ EC-SERS in catalysis. Through this review paper, we aim to attract greater attention to the use of in situ EC-SERS in catalysis studies and introduce versatile methodologies and techniques for catalytic studies that will result in superior performance.

Epitaxial crystallization is a key mechanism by which efficient nucleating agents (NAs) promote the nucleation of semicrystalline polymers, relying on both lattice and topographic matches between polymer crystals and nucleating substrates at the nucleation interface. However, when these two factors are comparable, the effect of chemical structural variations at the nucleation interface on polymer epitaxial nucleation remains poorly understood. In this study, two nucleation interfaces between isotactic polypropylene (iPP) beta-crystal and aromatic bisamide beta-NAs with comparable lattice and topographic matches were constructed, using a newly developed beta-NA, N-cyclohexyl-N '-cyclopentylterephthalamide (CHCPT), and a commercial beta-NA, N,N '-dicyclohexylterephthalamide (DCHT). The influence of the nucleation interface modification (adjustment in the beta-NA chemical structure, e.g., the half replacement of cyclohexyl by cyclopentyl) on iPP crystallization and epitaxial nucleation was systematically investigated using wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), fractionated crystallization, and molecular mechanics (MM) calculations. Compared to DCHT, CHCPT shows higher beta-nucleation selectivity, greater nucleation efficiency, and faster overall crystallization rate toward iPP. MM simulations reveal that at the nucleation interface, CHCPT exhibits a lower average interfacial energy with iPP beta-crystal than DCHT, corresponding to a reduced interfacial free energy difference (Delta sigma) toward iPP beta-crystal as determined from fractionated crystallization studies. The lower Delta sigma reduces the nucleation energy barrier, thereby enhancing the beta-nucleation rate in the iPP/CHCPT system. These findings reveal that chemical structural modification at the nucleation interface via the variation in the beta-NA's chemical structure influences the intermolecular interactions between beta-NA and iPP and ultimately affects the epitaxial nucleation rate and crystallization behaviors of iPP. This work provides new insights into the mechanism by which the nucleation interface affects the epitaxial nucleation ability of nucleating agents and expands the understanding of rational molecular design for high-efficiency nucleating agents.

Through the hydrothermal synthesis of indium-doped titanium dioxide (In-TiO2), we observed that the indium element intricately integrated into the rutile TiO2 lattice, leading to surface protrusions on the nanorods, forming aggregated nanorod structures. This unique nanostructure not only significantly increases the specific surface area of the nanomaterial but also effectively enhances the efficiency of charge transfer and light absorption. Through validation by various structural characterization methods, including high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS), we confirmed the presence of this structure. This series of validations provides a solid theoretical foundation and experimental evidence for our research. The performance test results show that at 1.23 V, the In-TiO2 exhibits an impressive photocurrent density of 4.78 mA cm(2) compared to the standard reference electrode, 3.5 times higher than that of pure TiO2 under AM 1.5 G illumination conditions. Furthermore, the hydrogen production rate of In-TiO2 is approximately 0.103 mmol h cm(-2), significantly higher than that of pure rutile TiO2, which is 0.046 mmol h cm(-2). This study profoundly reveals the importance of indium doping in the TiO2 lattice for enhancing the efficiency of photo-catalytic hydrogen production, providing valuable insights for the future development of photocatalytic technology. As research on novel photocatalysts advances, we look forward to further breakthroughs and progress, aiming to make greater contributions to addressing energy and environmental challenges.

Photoelectrochemical(PEC)hydrogen production holds great promise for applications in energy production.A novel strategy characterized by simplicity,stability,and high efficiency is developed to significantly boost the PEC performance of TiO2(anatase)nanotube arrays(TNTAs).This strategy entails a series of treatments,including a conventional anodic oxidation(etching)process,a primary annealing treatment,and a secondary annealing treatment via impregnation.As a result,nickel phosphide(Ni2P)is composited onto well-ordered ti-tanium dioxide(anatase)nanotube array photoanodes(Ni2P/TNTAs),which exhibit hugely improved PEC H2 generation performance.A thorough and systematic investigation is conducted to comprehensively analyze the morphology,semiconductor band-gap structure,and PEC H2 production performance of the Ni2P/TNTAs com-posites.The experimental results demonstrate that under identical experimental circumstances,the measured photocurrent density of the Ni2P/TNTAs photoanode exhibits a 6.63-fold increase relative to that of TNTAs.The H2 production rate of Ni2P/TNTAs reaches 182.96 μmol/cm2,6.10 times higher than that of pure TNTAs.The excellent interfacial charge transfer pathway at the Ni2P/TiO2 interface promotes photogenerated carrier separation and electron transfer from TiO2 to Ni2P.This method offers a valuable reference for designing highly efficient PEC H2-production catalysts.