Search Results (4)

The exploration of high-performance, low-cost, and dual-function electrodes is crucial for anion exchange membrane water electrolysis (AEMWE) to meet the relentless demand for green H₂ production. In this study, a heteroatom-doped carbon-cage-supported CoSe₂@MoSe₂@NC catalyst with a formicarium structure has been fabricated using a scalable one-step selenization strategy. The component-refined bifunctional catalyst exhibited minimal overpotential values of 116 mV and 283 mV at 10 mA cm⁻² in 1 M KOH for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively. Specifically, rationally designed heterostructures and flexible carbonaceous sponges facilitate interfacial reaction equalization, modulate local electronic distributions, and establish efficient electron transport pathways, thereby enhancing catalytic activity and durability. Furthermore, the assembled AEMWE based on the CoSe₂@MoSe₂@NC bifunctional catalysts can achieve a current density of 106 mA cm⁻² at 1.9 V and maintain a favorable durability after running for 100 h (a retention of 95%). This work highlights a new insight into the development of advanced bifunctional catalysts with enhanced activity and durability for AEMWE. Full article

Promising results were recently reported for hierarchical ion-exchange membranes, fabricated by the UV crosslinking of a thin functional coating on a porous substrate, on model NaCl solution demineralization by electrodialysis (ED). Hierarchical anion-exchange membranes (hAEMs) have never been tested with complex solutions to demonstrate their potential use in the biofood industry. The impact of three different crosslinking densities of the ion-exchange coating (EbN-1, EbN-2 and EbN-3) on the performances of whey demineralization by ED was investigated and compared with commercial AMX. The results showed that by increasing the coating crosslinking density, the membrane conductivity decreased, leading to an increase in the global system resistance during whey demineralization (from +28% to +64%). However, 18% sweet whey solutions were successfully treated until 70% demineralization for all membranes. The energy consumption (averaged EbN value of 14.8 vs. 15.1 Wh for AMX) and current efficiency (26.0 vs. 27.4%) were similar to the control. Potential fouling by non-protein nitrogen was detected by ATR-FTIR for hAEMs impacting some membranes properties and ED performances. Overall, EbN-1 obtained results were comparable with the benchmark and can be considered as an alternative membrane for whey demineralization by ED and other applications in the demineralization of complex products from the food industry. Full article

The electrocatalyst of oxygen reduction reactions is one of the basic components of a fuel cell. In addition to costly Pt/C benchmark catalysts, cost-effective carbon-based catalysts have received the most attention. Enormous efforts have been dedicated to trade off the catalyst performance against the economic benefit. Optimizing composition and/or structure is a universal strategy for improving performance, but it is typically limited by tedious synthesis steps. Herein, we have found that directly introducing CNT into MOF-derived carbonaceous nanopolyhedra, i.e., introduced carbon nanotubes (CNTs) penetrated porous nitrogen-doped carbon polyhedra (NCP) dotted with cobalt nanoparticles (denoted as CNTs-Co@NCP), can optimize the catalytic activity, stability, and methanol tolerance. The hierarchical architecture combines the 0D/1D/3D Co/CNT/NCP interfaces and 1D/3D CNT/NCP junctions with the frameworks with a greatly exposed active surface, strengthened mass transport kinetics, stereoscopic electrical conductivity networks and structural robustness. The sterical self-consistency of MOF-self-assembly triggered by introduced CNTs demonstrates tactful ORR electrocatalytic activity regulation. Eventually, the CNTs-Co@NCP showed a half-wave potential (E_1/2) of 0.86 V and a diffusion-limited current density (J_L) of 5.94 mA/cm² in alkaline electrolyte. The CNTs-Co@NCP was integrated into the cathode of a direct methanol fuel cell (DMFC) with an anion-exchange membrane, and an open-circuit voltage (OCV) of 0.93 V and a high power density of 46.6 mW cm⁻² were achieved. This work successfully developed a catalyst with competitive ORR performance through plain parameter fine-tuning without complex material design. Full article

This paper presents a novel, cost-effective approach to the fabrication of composite anion exchange membranes (AEMs). Hierarchical AEMs have been fabricated by coating a porous substrate with an interpenetrating polymer network (IPN) layer where poly(vinylpyrrolidone) (PVP) is immobilized in a crosslinked matrix. The IPN matrix was formed by UV initiated radical crosslinking of a mixture of acrylamide-based monomers and acrylic resins. The fabricated membranes have been compared with a commercial material (Fumatech FAP 450) in terms of ionic transport properties and performance in a vanadium redox flow battery (VRFB). Measures of area-specific resistance (ASR) and vanadium permeability for the proposed membranes demonstrated properties approaching the commercial benchmark. These properties could be tuned by changing the content of PVP in the IPN coating. Higher PVP/matrix ratios facilitate a higher water uptake of the coating layer and thus lower ASR (as low as 0.58 Ω.cm²). On the contrary, lower PVP/matrix ratios allow to reduce the water uptake of the coating and hence decrease the vanadium permeability at the cost of a higher ASR (as high as 1.99 Ω.cm²). In VRFB testing the hierarchical membranes enabled to reach energy efficiency comparable with the commercial AEM (PVP_14—74.7%, FAP 450—72.7% at 80 mA.cm⁻²). Full article