Hydrogen is emerging as a sustainable energy source that can reduce fossil fuel reliance and associated environmental impact. However, it poses embrittlement challenges for storage and transport materials that affect the widespread deployment of the hydrogen economy. Surface modification of materials by employing coatings, thermochemical, mechanical treatments, and others modifies surface chemistry, microstructure, stress states, and enhances surface integrity. These surface modification methods form physical or chemical barriers that impede hydrogen permeation and lower hydrogen-induced degradation. Though an unfavorable combination of thermodynamic properties, hydrogen solubility, and hydrogen diffusivity of the modified surfaces promotes hydrogen embrittlement mechanisms. This review focuses on a comprehensive overview of various surface modification techniques applied to base materials to counter their hydrogen embrittlement susceptibility. This work emphasizes the relationship between the surface modification methods and their effects on microstructural and mechanical properties, and their contribution to hydrogen storage and transport solutions. Additionally, limitations, challenges, and research gaps related to these surface modification techniques for materials in hydrogen infrastructure are discussed.

Cu-based catalysts have attracted significant attention due to their cost-effectiveness and environmental compatibility, yet their pore structure optimization and surface engineering remain underexplored. Herein, we report a hierarchical micro-nanoporous composite (Pt-MNPCuO_x) with antennule-like surface incorporating ultra-low Pt nanoclusters (Pt NCs, 1.20 wt%), through integrating a self-exothermic/dealloying with impregnation strategy based on Cu-Al binary eutectic precursors. The modification of Pt NCs promotes the surface structure evolution with the CuO_x matrix through tuning the ratio of Cu/Cu⁺/Cu²⁺. The synergy of hierarchical porosity/antennule-like surface and Pt/CuO_x heterogeneous interface broadens the exposure of active sites, collaboratively enhancing the electron transfer and facilitating the light absorption. Theoretical calculations effectively demonstrate that the introduction of Pt optimizes the primary active site by regulating the electron distribution and the synergy between Pt NCs on the surface and CuO_x accelerates the reaction kinetics. Consequently, the optimized material demonstrates superior multifunctional catalytic performance for alkaline hydrogen/oxygen evolution reaction (HER/OER) (77 mV/275 mV@10 mA cm⁻²), coupled with 92.43 % methyl orange (MO) degradation efficiency under visible light within 10 min. This work validates a catalyst design where surface structural evolution through innovative synthesis strategies enables multifunctional catalytic behavior, potentially promising the construction and application of Cu-based material in environmental engineering.

For environmental management purposes, industrial alkaline waste streams are essential to be filtered effectively. Here, porous Zr-Al intermetallic compounds were prepared using a rapid self-exothermic reaction with a preventative holding treatment. The pre-heating treatment for thermal-adjustment accelerates the solid-state diffusion kinetics and reduces the heat released by the thermal explosion reaction (TE). The porous Zr-Al compounds were structurally reconstructed using the 3D X-ray microscopy (3D-XRM) technique, through which the porosity, pore connectivity, and permeability properties were semi-quantitatively analyzed in conjunction with the reconstructed model. In-situ high-temperature synchrotron X-ray diffraction (HT-SXRD) was employed to reveal the phase constitution evolution as a function of temperature, underpinning the effectiveness of the pre-heating treatment and revealing the formation of thermo-dynamically stable intermetallic phases. The complete reaction between Zr and Al is facilitated by the pre-heating treatment, producing a homogeneous pore-skeleton structure and inhibiting microcrack formation with superior connectivity and permeability properties. Consequently, optimal sample 570/700 shows excellent filtering properties due to the uniformly distributed and inter-connected pores. The superior corrosion resistance further evidences the expedited passivation film formation, combining with the homogeneous pore structure and stable intermetallic composition, which altogether improves substrate protection and mitigates electrochemical degradation processes. The structure-function integrated porous Zr-Al provides a meaningful path and shows the potential for filtration applications of industrial wastewater/gas. 

Commercial zeolites are crystalline aluminosilicate materials with high surface area and porosity which can be used in several applications. This study aims at adding luminescent functionality to the zeolite network, either enabling optical monitoring of the capturing process or towards the development of efficient light-emitting materials. Two representative commercial zeolites were chosen: 5A and 13X, adding europium (Eu³⁺) by an ion-exchange process. The effects of different solvents (water and ethanol) and thermal treatments on the structural and optical properties of the doped zeolites were investigated. The results demonstrate that 13X zeolites have superior Eu uptake and luminescent properties compared to 5A. XRD analysis suggests that Eu exchange can stress and disorder the network, which is recovered by annealing up to 600 °C. Instead, a higher temperature of 800 °C induces the collapsing of the porosity, with partial amorphization and significant reduction of the surface area of the material. The optical analysis showed that the PL intensities for 13X samples can be 60 times higher than those obtained for 5A samples. Moreover, ethanol emerged as a superior solvent to water, avoiding the presence of -OH vibrational energies detrimental to the luminescence of rare earth ions.

Three-dimensional (3D) graphene-based composite materials (3D GBCMs) have emerged as promising candidates for addressing critical challenges in water pollution remediation. This review selectively highlights the recent advancements in the application of 3D GBCMs to remove a wide range of contaminants, including heavy metals, dyes, salts, and pharmaceutical residues, from water. They owe their efficacy to their large surface area, interconnected porous structure, and functionalization potential. Three-dimensional GBCMs are promising materials for water filtration, offering capabilities such as heavy metal ion adsorption, the photocatalytic degradation of organic pollutants, and advanced desalination techniques like capacitive deionization (CDI) and solar desalination, thus providing sustainable solutions for obtaining freshwater from saline sources. Additionally, the factors influencing the pollutant removal capacities of 3D GBCMs, such as their material morphology, particle size, and porosity, are briefly discussed. Notably, the effect of the particle size on pollutant removal has not been extensively studied, and this review addresses that gap by exploring it in detail. Future research directions are also proposed, emphasizing the optimization and broader application of 3D GBCMs in environmental remediation. This review aims to provide valuable insights into the design and practical implementation of 3D GBCMs, offering guidance for their continued development in sustainable water treatment.

Nb-based refractory alloys are among those available materials for ultrahigh-temperature applications, while the trade-off between mechanical properties and oxidation resistance is a long-standing scientific challenge. Two commercial Nb alloys, C103 (Nb92.5Hf5.5Ti2, at.%) and WC3009 (Nb74.5Hf20W5.5, at.%), both with good room-temperature ductility but with various high-temperature strength, were modified here in this work with the intention to simultaneously achieve high strength at high temperatures, reasonable ductility at room temperature, and decent oxidation resistance. Particularly, the contents of alloying elements Hf, W and Ti were varied with reference to C103 and WC3009, considering Hf is good for strength and not detrimental to room-temperature ductility, W is particularly useful for the high-temperature strength, and Ti helps to improve oxidation resistance. The mechanical properties of these modified Nb-based refractory alloys were measured at room temperature and 1200 °C, and their oxidation resistance at 800 °C, 1000 °C and 1200 °C was also evaluated. Among the newly developed Nb-based refractory alloys, Nb68.5Hf15Ti10W6.5 (10Ti) and Nb55.5Hf20Ti15W9.5 (15Ti) showed much improved oxidation resistance compared to C103 and WC3009, at a relatively small cost of reduced high-temperature strength compared to WC3009. The alloying effect of Hf, W and Ti on the mechanical properties at both room-temperature and high-temperatures, the oxidation resistance, and more importantly their balance was discussed, providing important insights into the further development of Nb-based refractory alloys targeting ultrahigh-temperature applications.

The advancement of modern 3D printing technologies has opened the possibilities to fabricate different spectrums of materials using these technologies. Binder jetting 3D printing is a shaping-debinding-sintering-based Additive manufacturing process that selectively fabricates the parts in a layer-by-layer fashion using the local imprinting of polymeric binder. This study aims to develop cobalt and nickel-free TiC-FeCr-based cermets that will contribute to the development of cermets towards green and cost-efficient materials. An effective approach to increase the densities of printed parts was to replace unimodal powder feedstocks with bimodal powders. Therefore, this work employed bimodal spherical powder (TiC and 430L ferritic stainless steel) to promote better densification of the cermet parts. Liquid phase vacuum sintering has been performed with different sintering temperatures to consolidate the cermet parts. Detailed analyses of the microstructure evolution, phase formation, and mechanical properties (hardness and fracture toughness) have been conducted. Further, thermodynamic simulations were conducted to calculate the phase diagram of the proposed cermet using the Thermo-Calc program. Microstructural analysis of consolidated cermets reveals a direct correlation between sintering temperature and carbide grain size, affecting their mechanical and physical properties. The best hardness and fracture toughness properties of TiC-FeCr-based cermets are 1102 ± 13 HV30 and 12.74 ± 1.38 MPa m1/2 respectively, were obtained after sintering at 1450 °C. Moreover, a systematic comparison is conducted with the same cermet composition fabricated with different additive manufacturing processes based on Laser powder bed fusion and Binder jetting 3D printing technology, demonstrating the potential and limitations of both technologies to fabricate brittle materials such as cermets.

Tailoring a highly active and stable alkaline electrocatalyst endowed with an ultra-low electron transfer energy barrier for hydrogen/oxygen evolution reactions (HER/OER) has remained elusive to date. Herein, a defect-rich nanoporous Co^2+δ-incorporated RuO₂ (Co/RuO₂) catalyst was proposed that offered low overpotential and good stability for alkaline HER/OER. Ov–Ru–O–Co coordination under the electron coupling constructed by slight anchoring of Co^2+δ at Ru^4+δ sites played a pivotal role in optimizing the reaction energy barrier of the intermediates. Theoretical calculations suggested that Ov–Ru–O–Co coordination effectively optimized the primary active site by modulating the electron structure and position of the d-band center. This refinement enhanced the adsorption/desorption of reactive species, facilitating the overall progression of the catalytic reactions. Consequently, the optimal Co/RuO₂-1/50 catalyst achieved an ultralow overpotential at 10 mA cm⁻¹, an impressive Tafel slope for both HER (26 mV, 54 mV dec⁻¹) and OER (243 mV, 88 mV dec⁻¹) and an outstanding stability for over 100 h for OER. This work offers a practical roadmap for the development of noble metal-based electrocatalysts that exhibit high activity/stability for alkaline HER/OER.

In this study, a zeolitic adsorbent (AGW-ZA) was successfully developed from glass waste (GW)-derived aluminosilicates. The GW, serving as the starting material, underwent alkaline activation and hydrothermal treatment to yield the AGW-ZA adsorbent, which exhibited a surface area of 216.48 m2/g. The AGW-ZA demonstrated significantly higher ammonium (NH4+) ion adsorption (142.5 mg/g at 1000 mg/L) than pristine GW (80.0 mg/g). Optimal adsorption experimental parameters were identified (0.1 g dosage, pH = 7, and 10 h contact time) to determine the maximum NH4+ ions’ adsorption potential by adsorbents. Kinetic and isotherm models were applied to experimental data to describe the adsorption mechanisms. The pseudo-second-order model provided the best fit for both AGW-ZA and pristine GW, indicating that the adsorption process is followed by chemical interaction via ion exchange. Regarding isotherms, the Freundlich model was most suitable for AGW-ZA, signifying that NH4+ ions adsorbed on heterogeneous adsorbent surfaces by forming multilayers, while the Temkin model fit the pristine GW data, indicating the chemisorption nature with medium adsorbate–adsorbent interactions above the heterogeneous surface. This study explores the potential of transforming discarded GW into a high-performance zeolitic adsorbent for the mitigation of environmental pollution by removing NH4+ ions from wastewater while simultaneously addressing waste management challenges.