Protonic ceramic fuel cells (PCFCs) have attracted more interest than solid oxide fuel cells (SOFCs) due to their potential to be operated at lower temperatures, therefore, addressing the limitation of high-temperature oxygen ion conducting SOFC. Layered double perovskite with triple conducting (H+/O2-/e-) properties, such as PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF), have demonstrated outstanding performance as cathodes in PCFCs. Our investigation on molybdenum-doped (Mo-doped) PBSCF showed that high valence Mo doping is an effective strategy for substantially promoting the formation of oxygen vacancy and accelerating the overall cathodic reaction. The improved oxygen reduction reaction (ORR)-related kinetics are reflected by the reduced polarization resistance (Rp) of PBSCFM01 (0.052 Ω·cm2 at 650 °C) and the enhanced peak power density (PPD) of the PBSCFM01 cell (817 mW·cm-2 at 650 °C), corresponding to a 75% decrease in Rp and a 44% increase in PPD compared with pure PBSCF. Mo doping promotes the formation of oxygen vacancies, which optimizes the lattice structure and facilitates oxygen ion transport. In addition, Mo incorporation improves the charge transfer kinetics and overall electrical conductivity, with the PBSCFM01 sample exhibiting a maximum conductivity of 1051 S/cm at 250 °C─about 15% higher than that of pure PBSCF. Density functional theory calculations were further performed to elucidate the role of Mo incorporation in modulating oxygen vacancy formation. The theoretical results are in excellent agreement with the experimental observations, providing atomic-scale insight into the enhanced cathodic activity. This work demonstrates Mo as effective dopant for layered double perovskite materials to develop high oxygen reduction reaction activity cathode material PCFCs.

This work investigates proton conduction through a wide range of 2D graphene-like crystals using density functional theory calculations. Our goal focused on understanding the impact of the membrane’s chemical constitution on proton permeability, with particular attention to the effect of sequential substitution using non-metallic elements such as boron, nitrogen, silicon, sulfur, and phosphorus. Results indicate that boron-doped graphene reduces the proton permeation energy barrier, being comparable with values for hexagonal boron nitride. In contrast, nitrogen-doped graphene exhibits a significantly high energy barrier (>4 eV) for proton permeation, suggesting that it is unlikely to support proton conduction at room temperature without having defects on the 2D-monolayer. The use of other elements (O, Si, S, and P) generates a broad spectrum of energy barriers, with distinct trends correlating to changes in pore size driven by the elongation or contraction of the 6-membered rings containing the dopants. In comparison, pure 2D-materials such as phosphorene, silicene, and germanene also arise as promising candidates for proton exchange membrane (PEM) applications due to relatively low proton permeation barriers. However, the increased pore size in these materials may reduce their impermeability to other gases, potentially affecting the performance of the PEM. In addition, we further examined the synergistic effects of multi-element 2D materials, with gallium nitride emerging as a candidate capable of simultaneously enhancing proton permeability and improving membrane mechanical and thermal robustness. This work highlights the importance of exploring additional hetero-doped 2D-materials, where untapped chemical properties may offer further opportunities for optimizing PEM performance.

Herein, we have designed the all-nanoporous fillers and hydrogen-bonded organic framework (HOF) matrix, achieving high-permeance H2 purification. The hetero-MOF facilitates the heterogeneous nucleation, offsetting the need for a highly supersaturated solution to achieve sufficient nucleation density during solution processing. Continuous MOF/HOF ANC membranes are realized by suppressing the homogeneous nucleation, equilibrating the nucleation driving force with the molecular attachment rate, and balancing the nutrient supply and demand. The optimized copper 1,4-benzene dicarboxylate nanosheets (ns-CuBDC)/HOF-30-100 (30 means that HOF monomer concentration is 30 mgmL-1 and 100 represents that the temperature for solvent evaporation is 100 degrees C) ANC membrane shows synchronously improved H2 permeance and H2/CH4 selectivity by 562% and 241% compared to the pristine HOF membrane. The ns-CuBDC/HOF-30-100 ANC membrane inherits the pressure-responsive behavior from the parent HOF, exhibiting further improved H2 permeance up to 9842 gas permeation units (GPU) and slightly changed H2/CH4 selectivity of 30.01 at 2.0 bar. The MOF/HOF ANC membrane manifests that incorporating a porous hetero-phase effectively upgrades the gas separation performance, and the HOF matrix circumvents the performance constraints of the traditional polymer matrix while preserving the solution-processability.

Breaking the long-standing permeability-selectivity trade-off remains a central challenge in membrane-based carbon dioxide separations. Here we report a heteroatom-engineering strategy that leverages structurally precise covalent organic frameworks (COFs) to transcend this limitation in mixed matrix membranes (MMMs). Two isostructural, π-conjugated two-dimensional COFs, TUS-621 and TUS-622, were rationally designed through symmetry-guided reticulation of a hexatopic triphenylene node with oxygen- and sulfur-containing diamine linkers, respectively, enabling systematic modulation of pore surface chemistry without altering topology. When incorporated into a Pebax polymer matrix, these COFs function as CO2-philic, molecularly defined transport domains that synergistically couple preferential CO2 sorption with ordered and fast diffusion channels. The optimized TUS-621/Pebax-10% membrane exhibits a CO2 permeability of 433 Barrer with a CO2/CH4 selectivity of 55.3 under mixed-gas conditions, decisively surpassing the 2008 Robeson upper bound for CO2/CH4 separation while simultaneously achieving high CO2/H2 separation performance (CO2 permeability of 407 Barrer and selectivity of 25.2). Comprehensive pressure- and temperature-dependent permeation studies reveal that selectivity remains remarkably stable over 2-10 bar and 25-100 °C, underscoring the robustness of the COF-enabled transport pathways. Long-term operation over 30 days shows negligible performance decay, highlighting excellent resistance to physical aging and interfacial degradation. Comparative analysis establishes that oxygen-rich pore environments in TUS-621 impart stronger CO2 affinity and higher accessible surface area than the sulfur-containing analogue, directly translating molecular-level design into macroscopic separation performance. This work demonstrates that heteroatom-engineered COFs provide a powerful platform for overcoming fundamental transport trade-offs and advancing MMMs toward practical, high-efficiency CO2 separations.

Based on the magnetic sensitivity of Fe3O4 in various fields, we aimed to propose a one-step solvothermal process for the synthesis of single-phase Fe3O4 induced by the reaction medium and urea, avoiding high-temperature reduction in H2 or N2 atmospheres. Feasibility was tested with purified water (H2O), methyl alcohol (MA), ethyl alcohol (EA), and ethylene glycol (EG) as reaction media. The findings indicated that the solvothermal reaction system utilizing EA was more effective for the synthesis of cubic magnetic Fe3O4. Optimal conditions for synthesizing pure Fe3O4 were obtained by optimizing the urea amount and solvothermal reaction parameters. The optimal formulation consisted of 10 mmol of FeCl3, 80 mmol of urea, and 60 mL of EA subjected to a solvothermal process at 200 °C for 12 h. The resulting Fe3O4 (magnetite, cubic) exhibited commendable crystallization with a morphology of acicular aggregates and displayed excellent magnetic sensitivity properties with a magnetization of 92.2 emu/g at 15,000 Oe. The photocatalytic degradation behaviors of the resulting Fe3O4 to Methyl Orange, Orange G, and Acid Red 37 azo dyes and the repeated degradation performance of Methyl Orange dye were investigated. Nearly complete degradation of Methyl Orange dye occurred after 2.0 h of photocatalytic reaction, while Orange G and Acid Red 37 dyes achieved similar results after 3.5 and 4.5 h, respectively. The exploration strategy in this work for synthesizing magnetic Fe3O4 can be applied to design and fabricate other metal oxides or composites, potentially resulting in novel discoveries in morphology or performance.

Two-dimensional (2D) materials emerge as promising alternatives to conventional polymer-based proton exchange membranes (PEMs) due to their high proton conductivity, mechanical robustness, and surface tunability. Here we present an integrated framework combining ab initio molecular dynamics (AIMD) simulations and machine learning (ML) to accelerate the discovery of proton- and hydrogen-transport properties over 866 nonmetallic 2D materials. Three ML models were trained using AIMD-derived permeation barriers from 488 materials, with Random Forest achieving the highest accuracy and revealing structure-property relationships that govern proton transport. Critical descriptors, including proton-atom distance, pore size, interlayer spacing, and electron affinity, emerged as key predictors of permeation behavior. H+/H2 selectivity through additional AIMD simulations allowed identifying 18 promising candidates, including the experimentally studied graphene and hexagonal boron nitride, thus supporting the robustness of our approach. Experimentally synthesized but barely explored materials, including 2D Si, Ge, TeC, TeCl, GeSe and CSe, emerged as strong candidates for proton conducting membranes. The framework further highlights theoretically stable compounds as unexplored opportunities for PEMs. By integrating atomic-scale simulations with data-driven models, this work provides both fundamental insights into proton permeation mechanisms and practical guidance for designing selective, high-performance nanomaterials for hydrogen energy technologies.

In photocatalysis, the nature of reactive oxygen species plays a pivotal role in determining product selectivity. Yet, selective generation of singlet oxygen (1O2) is particularly desirable for achieving targeted photooxidations. Herein, two new nanosized titanium-oxide clusters (TOCs) doped with Ce, Ti14Ce2 and Ti4Ce2, were synthesized and explored in the selective photocatalytic oxidation of benzyl alcohols to benzaldehydes under mild conditions. Interestingly, the titanium-oxide core of Ti14Ce2 is recognized as a fragment of anatase TiO2, positioning Ti14Ce2 as a molecular model for Ce-doped TiO2 nanoparticles. Ce-doping effectively reduces the bandgap energy of the clusters, enabling visible-light absorption and enhancing their photocatalytic properties. Moreover, it promotes efficient energy transfer to O2 for 1O2 generation by increasing spin-orbit coupling. Both clusters exhibited high activity and selectivity in the oxidation of benzyl alcohols to benzaldehydes under visible-light irradiation. Our findings not only expand the TOC family with novel Ce-doped members but also offer insights into designing photocatalysts at the atomic level to enhance 1O2 generation for selective photo-oxidations.

We describe the self-coacervation and nanocrystal topochemical photo-RAFT polymerization of ionic phenylalanine acrylamide. The charged monomer molecules undergo self-coacervation through nanoclustering, liquid-liquid phase separation, and crystallization within dense droplets in water at pH 7.0 and 25 degrees C, leading to ultrathin lamellar nanocrystal-containing droplets capable of well-controlled topochemical photo-RAFT polymerization. The reaction induces pathway-dependent self-assembly involving the one-dimensional (non)covalent polymerization of monomer nanoclusters into fibril bundles. Furthermore, monomer molecules within the crystal lattice undergo one-dimensional rearrangements guided by growing polymer segments, leading to the nanocrystal transition into perforated lamellar hollow sieves accompanied by decreased crystallinity, and followed by interfacial topochemical polymerization of monomer nanoclusters site-specifically along the newly activated sites of sieve edges, leading to sieve-centred parallel-growing fibrils. Further reaction leads to densely charged ultrathin fibril lamellae physically crosslinked by fibril network knots. Consequently, the well-controlled topochemical photo-RAFT polymerization up to >98% conversion was achieved shortly in 1 h under ecofriendly ambient aqueous conditions. This work provides a robust platform of the solid-state topochemical polymerization with unprecedentedly high molecular weight controllability.

We present the first comprehensive investigation of transition metal-substituted Hydroxyapatite (TM-HAP) materials for photocatalytic CO2 reduction (CO2RR). Density functional theory (DFT) was used to study in a systematic manner the stability of 3d, 4d, 5d transition metal dopants on the HAP (000̅1) surface, analyzing their stability, activity, and selectivity for photocatalytic CO2RR. DFT results allowed to narrow down the selection to three transition metal elements (Co, Ni, Mo) based on their structural stability, band structure and performance. A selective analysis of product formation for carbon monoxide and formate was made, showing that TM dopants facilitate the initial protonation step in the CO2 reduction by adsorbing H2 molecule on TM atoms and then dissociating it into two hydrogen atoms. The performance of Ni- and Co-HAP towards the reaction activity is consistent with experimental results. Mo-HAP stands as a new and attractive photocatalyst for further investigation, given its excellent predicted performance.

Covalent organic frameworks (COFs), which have layered stacking structures, extended pi-conjugation, and periodic frameworks have become a promising class of materials for a wide range of applications. However, their synthetic pathways frequently need high temperatures, enclosed systems under high pressures, an inert atmosphere, and extended reaction time, which restrict their practicality in real-world applications. Herein, the use of gamma irradiation is presented to synthesize highly crystalline COFs at room temperature under an open-air condition within a short time. This is demonstrated that there is no significant difference in crystallinity of COFs by gamma irradiation under air, N2 or Ar atmosphere conditions. Moreover, this approach can successfully fabricate COFs in the vessel with different degrees of transparency or even in a plastic container. Importantly, this strategy is applicable not only to imine linkage of COFs but also effective to the imide linkages of COFs. Most importantly, these COFs demonstrate improved crystallinity, surface area, and thermal stability in comparison to the corresponding materials synthesized via the solvothermal method. Finally, a COF synthesized through gamma irradiation exhibits remarkable photocatalytic activity in promoting the sacrificial hydrogen evolution from water, displaying a more catalytic efficiency compared with that of its solvothermal analogue. The advancement of new forms of energy sources has been the focus of research to develop more green and high-throughput synthetic techniques. In this work, gamma irradiation is used as a promising approach under an open-air condition at room temperature within a short time for the synthesis of high crystalline COFs. image

Hydrogels show promise in preventing inorganic catalysis aggregation during hydrogen evolution. However, the incompatible intrinsic properties of inorganics and hydrogels can cause catalyst release during the reaction. One solution is incorporating polymer photocatalysts into hydrogels, but low photocatalytic efficiency due to anti-synergetic effects between polymers and hydrogels remains a challenge. Herein, we developed all-in-one photocatalytic microreactors (PMRs) with excellent stability and efficiency by strongly entangling polymers with hydrogels and designing heterogeneous hydrogels. This approach prevents catalyst loss while achieving a high hydrogen evolution efficiency, self-healability, and stretchability. Moreover, PMRs maintain their efficiency even after they undergo freeze-drying and rehydration. Remarkably, we demonstrate the construction of PMRs into three-dimensional (3D) structures via 3D-printing at room temperature without additional supporting material. In light of these advantages, we have demonstrated a strategy for rapidly manufacturing PMRs with high stability, reactivity, and 3D-printability, which has significant potential for practical applications.

Graphical Abstract The Front Cover demonstrates the photoluminescence phenomenon in a large single crystal of [BnMIm]4[MnBr4]Br2. Bright green emission of the prepared material is achieved through rational structural design, which involves lowering the concentration of [MnBr4]2− tetrahedra (shown in dark green) in the crystal structure to reduce non-radiative relaxation and increasing the crystallinity of the material through π-π stacking between [BnMIm]+ cations (shown in grayscale). More information can be found in the Research Article by V. Sääsk, M. Kato, T.-L. Wu, H.-H. Chou and co-workers.

Converting solar energy into hydrogen energy using conjugated polymers (CP) is a promising solution to the energy crisis. Improving water solubility plays one of the critical factors in enhancing the hydrogen evolution rate (HER) of CP photocatalysts. In this study, a novel concept of incorporating hydrophilic side chains to connect the backbones of CPs to improve their HER is proposed. This concept is realized through the polymerization of carbazole units bridged with octane, ethylene glycol, and penta-(ethylene glycol) to form three new side-chain-braided (SCB) CPs: PCz2S-OCt, PCz2S-EG, and PCz2S-PEG. Verified through transient absorption spectra, the enhanced capability of PCz2S-PEG for ultrafast electron transfer and reduced recombination effects has been demonstrated. Small- and wide-angle X-ray scattering (SAXS/WAXS) analyses reveal that these three SCB-CPs form cross-linking networks with different mass fractal dimensions (f) in aqueous solution. With the lowest f value of 2.64 and improved water/polymer interfaces, PCz2S-PEG demonstrates the best HER, reaching up to 126.9 µmol h-1 in pure water-based photocatalytic solution. Moreover, PCz2S-PEG exhibits comparable performance in seawater-based photocatalytic solution under natural sunlight. In situ SAXS analysis further reveals nucleation-dominated generation of hydrogen nanoclusters with a size of ≈1.5 nm in the HER of PCz2S-PEG under light illumination.

Atomic Ag cluster bonding is employed to reinforce the interface between PF3T nano‐cluster and TiO2 nanoparticle. With an optimized Ag loading (Ag/TiO2 = 0.5 wt%), the Ag atoms will uniformly disperse on TiO2 thus generating a high density of intermediate states in the band gap to form the electron channel between the terthiophene group of PF3T and the TiO2 in the hybrid composite (denoted as T@Ag05‐P). The former expands the photon absorption band width and the latter facilitates the core‐hole splitting by injecting the photon excited electron (from the excitons in PF3T) into the conduction band (CB) of TiO2. These characteristics enable the high efficiency of H2 production to 16 580 µmol h−1 g−1 and photocatalysis stability without degradation under visible light exposure for 96 h. Compared to that of hybrid material without Ag bonding (TiO2@PF3T), the H2 production yield and stability are improved by 4.1 and 18.2‐fold which shows the best performance among existing materials in similar component combination and interfacial reinforcement. The unique bonding method offers a new prospect to accelerate the development of photocatalytic hydrogen production technologies.

Ten ionic manganese(II) complexes of [EMIm](2)[MnX2Y2] (EMIm=1-ethyl-3-methylimidazolium ion; X, Y=Cl, Br or I) and [BnMIm](2)[MnX2Y2] (BnMIm=1-benzyl-3-methylimidazolium ion; X, Y=Cl, Br or I) types were synthesized and studied in terms of their thermal and photophysical properties. Complexes with [BnMIm]+ cation were found to exhibit higher crystallinity, owing to the aromatic pi-stacking, and superior photoluminescent quantum yields, promoted by the increased Mn & sdot;& sdot;& sdot;Mn distance. For complexes with chlorine and bromine ligands efficient tunability of photophysical parameters was demonstrated. Out of all complexes, [BnMIm](2)[MnBr4] was found to have the highest photoluminescence quantum yield at room temperature (phi=0.59). To highlight the importance of a large Mn & sdot;& sdot;& sdot;Mn distance for achieving high phi values, a mixed-anion analog of complex [BnMIm](2)[MnBr4] was prepared, with the suggested formula of [BnMIm](4)[MnBr4]Br-2. The latter have shown a significant improvement in d-d absorption efficiency and a reduction in nonradiative deactivation, which led to an outstanding phi value of 0.97. Finally, the optical band gap of [BnMIm](4)[MnBr4]Br-2 was estimated to describe its applicability as light-emitting material.

Our study underscores that ICTDB, a polymer with one malononitrile substitution, outperforms in the HER and displays enhanced ultrafast charge transfer capabilities.

A hybrid composite of organic-inorganic semiconductor nanomaterials with atomic Au clusters at the interface decoration (denoted as PF3T@Au-TiO2 ) is developed for visible-light-driven H2 production via direct water splitting. With a strong electron coupling between the terthiophene groups, Au atoms and the oxygen atoms at the heterogeneous interface, significant electron injection from the PF3T to TiO2 occurs leading to a quantum leap in the H2 production yield (18 578 µmol g-1 h-1 ) by ≈39% as compared to that of the composite without Au decoration (PF3T@TiO2 , 11 321 µmol g-1 h-1 ). Compared to the pure PF3T, such a result is 43-fold improved and is the best performance among all the existing hybrid materials in similar configurations. With robust process control via industrially applicable methods, it is anticipated that the findings and proposed methodologies can accelerate the development of high-performance eco-friendly photocatalytic hydrogen production technologies.