Proton Generation Research Articles

GEM detector as a neutron spectrometer for fusion plasmas: some modelling and design aspects

Measuring fusion neutron spectra can give essential information on ion fuel ratio and ion temperature in the plasma core, which are the goals of the High-Resolution Neutron Spectrometry (HRNS) on ITER. At the highest fusion powers, this role is foreseen to be fulfilled by a Thin-foil Proton Recoil (TPR) system with ΔE-E silicon detectors. The concept of performing TPR neutron spectroscopy with a Gas Electron Multiplier (GEM), so-called NS-GEM, instead of solid-state detectors has recently been proposed in [6]. Based on simulation results, the concept of a compact NS-GEM detector has been developed and a demonstrator has been prepared, starting with a standard 3-stage GEM detector. Modelling efforts allowed evaluating the reachable energy resolution for such NS-GEM demonstrator, considering the following issues: neutron collimation, recoil proton generation efficiency, recoil proton scattering and energy losses in the converter and detector. In this contribution, some design and modelling aspects are briefly reviewed and directions of future research to improve the NS-GEM performances are drawn.

Tuning the Formation Kinetics of *OOH Intermediate with Hollow Bowl-Like Carbon by Pulsed Electroreduction for Enhanced H2O2 Production.

The electrochemical synthesis of hydrogen peroxide (H2O2) via the two-electron oxygen reduction reaction (2e- ORR) is a promising alternative to the conventional anthraquinone method. However, due to local alkalinization near the catalyst surface, the restricted oxygen replenishment and insufficient activated water molecule supply limit the formation of the key *OOH intermediate. Herein, a pulsed electrocatalysis approach based on a structurally optimized S/N/O tridoped hollow carbon bowl catalyst has been proposed to overcome this challenge. In an H-type electrolytic cell, the pulsed method achieves a superior H2O2 yield rate of 55.6 mg h-1 mgcat.-1, approximately 1.6 times higher than the conventional potentiostatic method (34.2 mg h-1 mgcat.-1), while maintaining the Faradaic efficiency above 94.6%. In situ characterizations, finite element simulations, and density functional theory analyses unveil that the application of pulsed potentials mitigates the local OH- concentration, enhances the water activation and proton generation, and facilitates oxygen production within the hollow bowl-like carbon structure. These effects synergistically accelerate the formation kinetics of the *OOH intermediate by the efficient generation of *O2 and *H2O intermediates, leading to superior H2O2 yields. This work develops a strategy to tune catalytic environments for diverse catalytic applications.

Cascaded Metalation of Two‐Dimensional Covalent Organic Frameworks for Boosting Electrochemical CO Reduction

Carbon monoxide reduction reaction (CORR) to yield value‐added methanol entails the delicate design of catalysts due to the large overpotential of this reaction. Especially, achieving precise modification of electrocatalysts while preserving the periodic alignment of active sites to optimize performance remains a significant challenge. Here, we report the cascaded metalation of phthalocyanine‐based COFs for selective reduction of CO to methanol. After implanting the secondary metal (Ni), CityU‐35 achieves a Faradaic efficiency (FE) of 48.4% at ‐0.85 V vs. RHE, surpassing that of CityU‐34 (2.1%) with only Co atoms. The enhanced methanol production originates from the optimization of electronic structure with improved *CO adsorption, which is substantiated by the spectroscopic shift in UV and X‐ray photoelectron spectroscopy and a stronger *CO signal in the in‐situ attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS). Theoretical calculations have demonstrated that the cascaded metalation with the introduction of secondary Ni sites in CityU‐35 not only improves the adsorption towards *CO intermediates but also supplies a fast generation of protons for the hydrogenation of *CO towards CH3OH. The optimized electronic structures with synergistic effects between Co and Ni sites after cascaded metalation reduce the energy barriers and improve the overall electroactivity.

Cascaded Metalation of Two-Dimensional Covalent Organic Frameworks for Boosting Electrochemical CO Reduction.

Carbon monoxide reduction reaction (CORR) to yield value-added methanol entails the delicate design of catalysts due to the large overpotential of this reaction. Especially, achieving precise modification of electrocatalysts while preserving the periodic alignment of active sites to optimize performance remains a significant challenge. Here, we report the cascaded metalation of phthalocyanine-based COFs for selective reduction of CO to methanol. After implanting the secondary metal (Ni), CityU-35 achieves a Faradaic efficiency (FE) of 48.4% at -0.85 V vs. RHE, surpassing that of CityU-34 (2.1%) with only Co atoms. The enhanced methanol production originates from the optimization of electronic structure with improved *CO adsorption, which is substantiated by the spectroscopic shift in UV and X-ray photoelectron spectroscopy and a stronger *CO signal in the in-situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS). Theoretical calculations have demonstrated that the cascaded metalation with the introduction of secondary Ni sites in CityU-35 not only improves the adsorption towards *CO intermediates but also supplies a fast generation of protons for the hydrogenation of *CO towards CH3OH. The optimized electronic structures with synergistic effects between Co and Ni sites after cascaded metalation reduce the energy barriers and improve the overall electroactivity.

Light-Driven Artificial Cell Micromotors for Degenerative Knee Osteoarthritis.

Combining artificial cellular compartmentalization and intelligent motion benefits of micro/nanomotors, light is used as energy input to construct an artificial cell-based micromotor capable of photosynthetic anabolism and intelligent directional movement. This system is assembled from phospholipids functionalized with F-ATP synthase and molybdenum disulfide (MoS2) nanoparticles (Vesical@MoS2-ATPase). The underlying mechanism involves the generation of protons (H+) through photo-hydrolysis of MoS2 nanoparticles within vesicles, which generates a local electroosmotic flow inside the vesicles and drives the negatively charged MoS2 toward light. The established proton gradient across the phospholipid membrane, in turn, drives the ATP synthase to catalyze ATP production. Both in vitro and in vivo models demonstrate that the micromotor can elevate local intracellular ATP levels upon light and improve the metabolism of denatured chondrocytes. This cell mimicry, with capabilities of migration and biosynthesis, emerges as a promising platform for the next generation of functional bio-interface.

Generation and Distribution of Protons in the Nucleus According to New Axioms and Laws

Generation and Distribution of Protons in the Nucleus According to New Axioms and Laws

Laser-driven proton acceleration beyond 100 MeV by radiation pressure and Coulomb repulsion in a conduction-restricted plasma

An ultrahigh-intensity femtosecond laser can establish a longitudinal electric field stronger than 1013 Vm−1 within a plasma, accelerating particles potentially to GeV over a sub-millimetre distance. Laser-accelerated protons with high brightness and picosecond duration are highly desired for applications including proton imaging and flash radiotherapy, while a major limitation is the relatively low proton energy achieved yet, primarily due to the lack of a controllable acceleration structure. Here, we report the generation of protons with a cutoff energy exceeding 110 MeV, achieved by irradiating a multi-petawatt femtosecond laser on a conduction-restricted nanometre polymer foil with a finite lateral size. The enduring obstacles in achieving ultrahigh laser contrast and excellent laser pointing accuracy were successfully overcome, allowing the effective utilization of size-reduced nanometre foils. A long acceleration structure could be maintained in such a quasi-isolated foil since the conduction of cold electrons was restricted and a strong Coulomb field was established by carbon ions. Our achievement paves the road to enhance proton energy further, well meeting the requirements for applications, through a controllable acceleration process using well-designed nano- or micro-structured targets.

Yttrium Doping of Perovskite Oxide La2Ti2O7 Nanosheets for Enhanced Proton Conduction and Gas Sensing Under HighHumidity Levels.

Water molecules from the environment or human breath are one of the main factors affecting the accuracy, efficiency, and long-term stability of electronic gas sensors. In this contribution, yttrium (Y)-doped La2Ti2O7 (LTO) nanosheets were synthesized by a hydrothermal reaction, demonstrating improved proton conductivity compared to their non-doped counterparts. The response of Y-doped LTO with the optimal doping concentration to 100 ppm NO2 at 43% relative humidity (RH) was -21%, which is four times higher than that of bare La2Ti2O7. As the humidity level increased to 75%, the response of Y-doped LTO further increased to -64%. Unlike the gas doping effect observed in previous studies of semiconducting metal oxides, the sensing mechanism of Y-doped LTO nanosheets is based on the enhanced dissociation of H2O in the presence of target NO2 molecules, leading to the generation of more protons for ion conduction. This also resulted in a greater resistance drop and thus a larger sensing response at elevated humidity levels. Our work demonstrates that proton-conductive oxide materials are promising gas-sensing materials under humid conditions.

Visualizing the dynamic evolution of light-sensitive Cu1+/Cu2+ sites during photocatalytic CO2 reduction with an advanced in situ EPR spectroscopy.

Visualizing the dynamic evolution of light-sensitive Cu1+/Cu2+ sites during photocatalytic CO2 reduction with an advanced in situ EPR spectroscopy.

Factors governing H3+ formation from methyl halogens and pseudohalogens

The formation of H3+ following the double ionization of small organic compounds via a roaming mechanism, which involves the generation of H2 and subsequent proton abstraction, has recently garnered significant attention. Nonetheless, a cohesive model explaining trends in the yield of H3+ characterizing these unimolecular reactions is yet to be established. We report yield and femtosecond time-resolved measurements following the strong-field double ionization of CH3X molecules, where X = OD, Cl, NCS, CN, SCN, and I. These measurements, combined with double-ionization-potential equation-of-motion coupled-cluster ab initio calculations used to determine the geometries and energetics of CH3X2+ dications, are employed to identify the key factors governing the formation of H3+ in certain doubly ionized CH3X species and its absence in others. We also carry out ab initio molecular dynamics simulations to obtain detailed microscopic insights into the mechanism, yields, and timescales of H3+ production. We find that the excess relaxation energy released after double ionization of CH3X molecules combined with substantial geometrical distortion that favors H2 formation prior to proton abstraction boost the generation of H3+. Our study provides useful guidelines for examining alternative sources of H3+ in the universe.

Investigation of Pre-Pulse Effects on Ultrashort-Pulse Laser Interaction with Structured Targets

The role of pre-plasma in the efficient generation of protons by intense laser-matter interaction from structured targets is investigated. Optimal energy coupling between laser and plasma is found by varying the fluence and arrival time of an independently controllable ultrashort pre-pulse with respect to the main interaction pulse. The coupling is evaluated based on the energy of the accelerated protons. The accelerated proton energy is maximized at optimal pre-pulse delay and fluence conditions. Plasma emission spectrum and Particle-in-Cell simulations provide a possible explanation of the obtained experiment results.

Regenerative Biomimetic Photosynthesis by Covalent-Organic Framework-Based Nanobiohybrids.

Biomimetic photosynthesis, which leverages nanomaterials with light-responsive capabilities, represents an innovative approach for replicating natural photosynthetic processes for green and sustainable energy conversion. In this study, a covalent-organic framework (COF)-based artificial photosynthesis system is realized through the co-assembly of adenosine triphosphate (ATP) synthase and a light-responsive proton generator onto an imine-based COF, RT-COF-1. This system demonstrates an ATP production rate of 0.64 µmol ATP per mg protein within 90 s of light exposure and, for the first time, exhibites regenerative ATP production through multiple light on/off cycles. Furthermore, the ATP generated by the system facilitates the biocoupling of monosaccharides into disaccharides, confirming the hybrid system's capability to convert solar energy into chemical energy in the form of organic molecules. This approach shows significant potential for renewable bioenergy generation, offering precise and reliable control over biochemical processes through artificial photosynthesis.

Electrochemically Controlled Deposition of Low-Crystalline Covalent Organic Frameworks on Nanocarbon Electrode Toward Metal-Free Oxygen Reduction Electrocatalyst.

Morphology-controlled synthesis of covalent organic frameworks (COFs) offers significant potential for electrochemical applications. However, controlling the deposition of nanometer-scale COFs on carbon supports remains challenging due to the need for a slow COF generation rate and the dispersion of carbon supports in liquid-phase synthesis. In this study, nanometer-scale COF/carbon composites are fabricated using electrochemically generated acid (EGA) to assist in the formation of imine-type COFs, which are then deposited onto pre-cast nanocarbon supports on an electrode. A monomer combination of tri(4-aminophenyl)-1,3,5-triazine and 2,5-dimethoxybenzene-1,4-dicarboxaldehyde is utilized due to their suitable oxidation potentials, with 1,2-diphenylhydrazine serving as the EGA source. Through proton generation driven by electrolysis conditions, controlled COF formation is achieved at the single nanometer scale, ranging from 6 to 30nm, on various nanocarbon supports. The COF/carbon electrode is evaluated as an oxygen reduction reaction (ORR) electrocatalyst, demonstrating superior performance compared to other COF-based electrode materials containing the 1,3,5-triazine moiety. The findings experimentally validate the efficacy of the EGA-assisted COF deposition method for nanostructure construction and its ability to enhance the properties of COF-based electrodes through morphology tuning.

Dynamic interfacial pH regulation with chitosan gel electrolyte for enhanced high-temperature Zn anode stability

Dynamic interfacial pH regulation with chitosan gel electrolyte for enhanced high-temperature Zn anode stability

A Well‐Coupled Supramolecular System Accelerates Photophosphorylation

AbstractSupramolecular assembly allows multiple chemical/bio‐components integrated as one system for cascade biochemical reactions. Herein the graphitic carbon nitrides (g‐C3N4) as photocatalyst trapped in a dipeptide hydrogel covering adenosine triphosphate (ATP) synthase accelerates the photophosphorylation through ATP synthesis. Self‐assembled N‐fluorenylmethoxycarbonyl diphenylalanine (Fmoc‐FF) as nanofibrils to allow g‐C3N4 nanosheets are embedded as a complex Fmoc‐FF/g‐C3N4 hydrogel. Fmoc‐FF gel exhibits good electronic coupling with g‐C3N4, which enables a photo‐induced proton generation. The transmembrane proton gradient can be established by ATP synthase‐lipid reconstituted on the surface of the Fmoc‐FF/g‐C3N4 hydrogel to enhance the ATP synthesis. It indicates that the Fmoc‐FF/g‐C3N4/ATP synthase‐lipid film can possess a longer‐term ATP production capability and allow repeated immersion for sustained ATP production. Such a hydrogel‐supported ATP synthesis platform is achieved by a procedure at a larger scale.

A Well-Coupled Supramolecular System Accelerates Photophosphorylation.

Supramolecular assembly allows multiple chemical/bio-components integrated as one system for cascade biochemical reactions. Herein the graphitic carbon nitrides (g-C3N4) as photocatalyst trapped in a dipeptide hydrogel covering adenosine triphosphate (ATP) synthase accelerates the photophosphorylation through ATP synthesis. Self-assembled N-fluorenylmethoxycarbonyl diphenylalanine (Fmoc-FF) as nanofibrils to allow g-C3N4 nanosheets are embedded as a complex Fmoc-FF/g-C3N4 hydrogel. Fmoc-FF gel exhibits good electronic coupling with g-C3N4, which enables a photo-induced proton generation. The transmembrane proton gradient can be established by ATP synthase-lipid reconstituted on the surface of the Fmoc-FF/g-C3N4 hydrogel to enhance the ATP synthesis. It indicates that the Fmoc-FF/g-C3N4/ATP synthase-lipid film can possess a longer-term ATP production capability and allow repeated immersion for sustained ATP production. Such a hydrogel-supported ATP synthesis platform is achieved by a procedure at a larger scale.

A Straightforward Model for Quantifying Local pH Gradients Governing the Oxygen Evolution Reaction.

The production and consumption of protons by an electrocatalyst will, under certain conditions, generate localized microenvironments with properties distinct from those of the bulk solution. These local properties are particularly impactful for reactions involving proton-coupled electron transfer, where the generation of locally basic or acidic environments may significantly influence the energy efficiency and reaction selectivity of the electrocatalyst. Whereas local pH environments have been observed and characterized in reductive half-reactions, including the CO2 reduction and hydrogen evolution reactions, the incompatibility of conventional techniques and materials has limited studies in oxidative half-reactions, including the oxygen evolution reaction (OER), which provides the reducing equivalents for solar-to-fuels electrolysis. With the straightforward parameters bulk pH, buffer composition and pKa, and mass transport, we develop a model for describing local pH as a function of current density regardless of the microscopic details of the mechanism. Using an acid-stable PbOx OER catalyst, we observe the formation and dissipation of pH gradients during the OER and validate the model with voltammetric and potentiometric studies. The model predicts how local acidic environments can develop over a narrow OER current density window, thus providing further motivation for the development of OER catalysts that are stable to acid, even when operating in basic aqueous conditions. More generally, the model is not restricted to the OER and is useful for determining the onset of local pH gradients for other electrocatalytic reactions that involve the consumption or generation of protons in energy conversion reactions.

Molten Salt-Assisted Synthesis of Ferric Oxide/M-N-C Nanosheet Electrocatalysts for Efficient Oxygen Reduction Reaction.

Efficient, stable, and low-cost oxygen reduction catalysts are the key to the large-scale application of metal-air batteries. Herein, high-dispersive Fe2O3 nanoparticles (NPs) with abundant oxygen vacancies uniformly are anchored on lignin-derived metal-nitrogen-carbon (M-N-C) hierarchical porous nanosheets as efficient oxygen reduction reaction (ORR) catalysts (Fe2O3/M-N-C, M═Cu, Mn, W, Mo) based on a general and economical KCl molten salt-assisted method. The combination of Fe with the highly electronegative O induces charge redistribution through the Fe-O-M structure, thereby reducing the adsorption energy of oxygen-containing substances. The coupling effect of Fe2O3 NPs with M-N-C expedites the catalytic activity toward ORR by promoting proton generation on Fe2O3 and transfer to M-N-C. Experimental and theoretical calculation further revealed the remarkable electronic structure evolution of the metal site during the ORR process, where the emission density and local magnetic moment of the metal atoms change continuously throughout their reaction. The unique layered porous structure and highly active M-N4 sites resulted in the excellent ORR activity of Fe2O3/Cu-N-C with the onset potential of 0.977V, which is superior to Pt/C. This study offers a feasible strategy for the preparation of non-noble metal catalysts and provides a new comprehension of the catalytic mechanism of M-N-C catalysts.

Overview and Recent Developments of the Frascati Laser for Acceleration and Multidisciplinary Experiments Laser Facility at SPARC_LAB

An overview of the 200 TW Frascati Laser for Acceleration and Multidisciplinary Experiments (FLAME) at the SPARC_LAB Test Facility at the National Laboratories of Frascati (LNF-INFN) is presented. The FLAME laser is employed to investigate different laser–matter interaction schemes, i.e., electron acceleration and secondary radiation sources through Laser Wakefield Acceleration (LWFA) or ion and proton generation through Target Normal Sheath Acceleration (TNSA), for a wide range of scientific areas including the biomedical applications. Finally, recently performed experimental campaigns within the EuAPS and EuPRAXIA frameworks are reported.

Glucose Oxidase-Based Glucose Biosensing with a Simple Dual Ag/AgCl Probe Conductivity Readout.

We describe a conductometric assay of the enzymatic conversion of glucose to gluconic acid by dissolved glucose oxidase (GOx), using the generation of proton and gluconate from the reaction product dissociation for glucose detection. Simple basics of ionic conductivity, a silver/silver chloride wire pair, and a small applied potential translate glucose-dependent GOx activity into a scalable cell current. Enzyme immobilization and complex sensor design, involving extra nanomaterials or microfabrication of electrode structures, are entirely avoided, in contrast to all modern electrochemical glucose biosensors. Assay calibration showed a response linearity up to 500 μM, with a sensitivity of about 1.3 nA/μM. Selectivity tests excluded signals from sugars other than glucose, and glucose quantifications with recovery rates close to 100% were reached with a model sample and a beverage. Easy use of elementary physicochemical phenomena and a satisfactory performance are assets of the proposed non-amperometric glucose biosensing strategy. Assay integration into a planar dual electrode platform, with or without microfluidic application option, is feasible because of the simplicity of the sensor readout and suggests a route to affordable glucose analysis in beverage, food, and body fluid samples.