Metal–carbon composites are extensively utilized as electrochemical catalysts but face critical challenges in mass production and stability. We report a scalable manufacturing process for ruthenium surface-embedded fabric electrocatalysts (Ru-SFECs) via conventional fiber/fabric manufacturing. Ru-SFECs have excellent catalytic activity and stability toward the hydrogen evolution reaction, exhibiting a low overpotential of 11.9 mV at a current density of 10 mA cm–2 in an alkaline solution (1.0 M aq KOH solution) with only a slight overpotential increment (6.5%) after 10,000 cycles, whereas under identical conditions, that of commercial Pt/C increases 6-fold (from 1.3 to 7.8 mV). Using semi-pilot-scale equipment, a protocol is optimized for fabricating continuous self-supported electrocatalytic electrodes. Tailoring the fiber processing parameters (tension and temperature) can optimize the structural development, thereby achieving good catalytic performance and mechanical integrity. These findings underscore the significance of self-supporting catalysts, offering a general framework for stable, binder-free electrocatalytic electrode design.

Applications of advanced oxidation processes (AOPs) in water treatment require addressing technological challenges such as developing low-cost techniques for nanocatalyst synthesis, overcoming mass transfer limitations, and enhancing the yield of reactive oxygen species (ROS). This study employs a simple sodium borohydride (NaBH4)-based reduction technique for synthesizing ultrathin amorphous cobalt-iron oxide nanosheets (A/Co3-Fe ONS) to activate peroxymonosulfate (PMS). These nanosheets were found to outperform crystalline nanosheets due to their abundant reactive sites, oxygen vacancies, and capability to produce ROS through O–O and S–O bond cleavage. Due to the nanoconfinement effect, converting A/Co3-Fe ONS into a lamellar membrane significantly enhances reactivity and efficacy (1290 times) compared to batch PMS-mediated AOP reactors. Quenching experiments, solid-state and solution-based electron paramagnetic resonance (EPR) spectroscopy facilitated delineation of the reaction mechanisms involving both radical and nonradical pathways. Finally, the A/CoFeOx membrane achieved efficient removal (>95 %) of various organic micropollutants (OMPs), ultrafast destruction (318 ms), and excellent stability (48 h) through redox-recycling facilitated by the redox-potential difference and oxygen vacancies. This strategy offers a low-temperature cost-effective alternative and may be considered for scale-up in water treatment.

Covalent organic frameworks (COFs) are an emerging class of highly porous crystalline organic polymers comprised entirely of organic linkers connected by strong covalent bonds. Due to their excellent physicochemical properties (e.g., ordered structure, porosity, and stability), COFs are considered ideal materials for developing state-of-the-art separation membranes. In fact, significant advances have been made in the last six years regarding the fabrication and functionalization of COF membranes. In particular, COFs have been utilized to obtain thin-film, composite, and mixed matrix membranes that could achieve effective rejection (mostly above 80%) of organic dyes and model organic foulants (e.g., humic acid). COF-based membranes, especially those prepared by embedding into polyamide thin-films, obtained adequate rejection of salts in desalination applications. However, the claims of ordered structure and separation mechanisms remain unclear and debatable. In this perspective, we analyze critically the design and exploitation of COFs for membrane fabrication and their performance in water treatment applications. In addition, technological challenges associated with COF properties, fabrication methods, and treatment efficacy are highlighted to redirect future research efforts in realizing highly selective separation membranes for scale-up and industrial applications.

Two-dimensional covalent organic frameworks (COFs) with uniform pores and large surface areas are ideal candidates for constructing advanced molecular sieving membranes. However, a fabrication strategy to synthesize a free-standing COF membrane with a high permselectivity has not been fully explored yet. Herein, we prepared a free-standing TpPa-SO3H COF membrane with vertically aligned one-dimensional nanochannels. The introduction of the sulfonic acid groups on the COF membrane provides abundant negative charge sites in its pore wall, which achieve a high water flux and an excellent sieving performance toward water-soluble drugs and dyes with different charges and sizes. Furthermore, the COF membrane exhibited long-term stability, fouling resistance, and recyclability in rejection performance. We envisage that this work provides new insights into the effect of ionic ligands on the design of a broad range of COF membranes for advanced separation applications.

Electrochemical reduction of aqueous nitrates has emerged as a sustainable and practical approach in combining water treatment and ammonia fertilizer synthesis. However, the development of highly integrated catalytic electrodes with consistently high activity from non-noble metals remains a challenging issue despite the potential to greatly decrease costs and promote real-world applications. Here, we report a high-performance electrode with electron-abundant surfaces obtained from direct boronization of nickel foam, rendering a stable ammonia yield rate of 19.2 mg h–1 cm–2 with high Faradaic efficiency of 94% for NO3–-to-NH3 conversion. The microprocessing lowers the work function and initiates a local electric field for the nickel foam by converting acid-stable surface nickel oxides into dyadic nanosheets composed of metallic nickel and amorphous nickel borates, thus promoting the adsorption and transformation of nitrate anions. Furthermore, the spent electrode enables a rapid and effective regeneration by undergoing another round of boronization, which ensures a long lifetime for the practical application of our electrode design.