Electrochemical CO₂ reduction (CO₂R) to chemicals and fuels has made tremendous progress since the introduction of gas diffusion electrodes (GDEs) to overcome mass-transfer limitations and enable industrial-scale current densities. The advancement in the field, however, has come with new challenges that are related to the stability and degradation of the GDE due to flooding issues, which currently hinder the scale-up. Here, we investigated the effect of six different binding materials (Nafion, polytetrafluoroethylene, Fumion, Pention, poly(vinyl alcohol), and polypyrrole) on the stability and performance of Ag-based GDEs for CO₂R to CO in alkaline media. All binders show a decrease in the Faraday efficiency (FE) of CO and increase in hydrogen evolution reaction over time. The most hydrophilic GDE based on polypyrrole can uphold a higher FE of CO for longer times, which is contrary to a common belief that low wettability is required for long-term stability. By using a range of tools (SEM-EDX, SEM-FIB, X-ray diffraction, and contact angle measurements) for the postelectrolysis characterization of the GDEs, we show that the performance loss is related to flooding, bi(carbonate) precipitation, and catalyst agglomeration. These results contribute to a better understanding of the stability issues in GDE-based CO₂ electrolyzers.

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Despite being the most widely used biomaterials in orthopedic surgery, metallic implants do not induce new bone growth because they are bioinert. Surface biofunctionalization of implants with immunomodulatory mediators is a recent approach to promote osteogenic factors that facilitate bone regeneration. Liposomes (Lip) can be used as a low-cost, efficient and simple immunomodulator to stimulate immune cells in favor of bone regeneration. Even though liposomal coating systems have been reported previously, their main disadvantage is their limited ability to preserve liposome integrity after drying. In order to address this issue, we developed a hybrid system in which liposomes could be embedded in a polymeric hydrogel namely gelatin methacryloyl (GelMA). Specifically, we have developed a novel versatile coating strategy using electrospray technology to coat implants with GelMA/Liposome without using adhesive intermediate layer. The two differently charged Lip (i.e., anionic and cationic) were blended with GelMA and coated via electrospray technology on the bone-implant surfaces. The results showed that the developed coating withstood mechanical stress during surgical replacement, and Lip inside GelMA coating stayed intact in different storage conditions for a minimum of 4 weeks. Surprisingly, bare Lip, either cationic or anionic, improved the osteogenesis of human Mesenchymal Stem Cells (MSCs) by inducing pro-inflammatory cytokines, even at a low dosage of Lip released from the GelMA coating. More importantly, we showed that the inflammatory response could be fine-tuned by selecting the Lip concentration, Lip/hydrogel ratio, and coating thickness to determine the timing of the release such that we can accommodate different clinical needs. These promising results pave the way to use these Lip coatings to load different types of therapeutic cargo for bone-implant applications.@en

Efficient and sustainable synthesis of performant metal/nitrogen-doped carbon (M-N-C) catalysts for oxygen reduction and evolution reactions (ORR/OER) is vital for the global switch to green energy technologies-fuel cells and metal-air batteries. This study reports a solid-phase template-assisted mechanosynthesis of Fe-N-C, featuring low-cost and sustainable FeCl₃, 2,4,6-tri(2-pyridyl)-1,3,5-triazine (TPTZ), and NaCl. A NaCl-templated Fe-TPTZ metal-organic material was formed using facile liquid-assisted grinding/compression. With NaCl, the Fe-TPTZ template-induced stability allows for a rapid, thus, energy-efficient pyrolysis. Among the produced materials, 3D-FeNC-LAG exhibits remarkable performance in ORR (E_1/2 = 0.85 V and E_onset = 1.00 V), OER (E_j=10 = 1.73 V), and in the zinc-air battery test (power density of 139 mW cm^-2). The multilayer stream mapping (MSM) framework is presented as a tool for creating a sustainability assessment protocol for the catalyst production process. MSM employs time, cost, resource, and energy efficiency as technoeconomic sustainability metrics to assess the potential upstream impact. MSM analysis shows that the 3D-FeNC-LAG synthesis exhibits 90% overall process efficiency and 97.67% cost efficiency. The proposed synthetic protocol requires 2 times less processing time and 3 times less energy without compromising the catalyst efficiency, superior to the most advanced methods.

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