Furfural is a key platform compound obtained from the conversion of lignocellulose and hemicellulose. It can be synthesized into liquid fuels through methods such as carbon carbon coupling, hydrogenation, and...
Manganese dioxide (particularly δ-MnO 2 ) is a promising cathode candidate for aqueous zinc-ion energy storage; however, its practical application is limited by structural instability and low electronic conductivity. To address these...
The overall energy efficiency of several electrochemical devices depends on the electrocatalytic overpotential consumed by the kinetically uphill anodic oxygen evolution reaction (OER), thus driving the pursuit for non-noble OER electrocatalysts with an optimum balance of activity and durability. Despite possessing good intrinsic activity toward the OER, the electrochemical performance of spinel Co3O4 is severely impacted by its low electrical conductivity. Herein, a (cobalt/molybdenum)-oxide composite series (CMO-T, temperature = 350, 450, 550 and 650 degrees C) was derived from the thermal annealing of a molecular sacrificial template (Co(H2O)6@MoO3) whose structure consists of [Co(H2O)6]2+ intercalated in the interlayers of alpha-MoO3. The subsequent thermal transformation leads to the formation of Co2+ rich Co3O4 and an interesting phase transformation of alpha-MoO3 at different temperatures, producing a unique composite of MoO2 and the Magneli phase Mo4O11, with Co3O4 (Co3O4/MoO2/Mo4O11) at 550 degrees C. CMO-550 (Co3O4/MoO2/Mo4O11) demonstrates remarkable OER as the dissolution of the molybdenum oxides promotes quick in situ reconstruction to cobalt oxyhydroxide - the OER active phase. The OER activity of CMO-550 is characterized by an overpotential of 340 mV at 20 mA cm-2, a low Tafel slope of 68 mV decade-1 and a faradaic efficiency of 94%, indicating fast OER kinetics and selectivity. Moreover, CMO-550 exhibits excellent electrocatalytic stability at 20 mA cm-2 for 140 hours (more than 5 days), in contrast to commercially sourced Co3O4. The latter shows limited morphological evolution upon anodic polarization and even undergoes severe particle aggregation, causing its gradual activity deterioration during electrolysis. This study attempts to unveil the advantage of metal-oxide/metal oxide heterostructures and how their individual contributions can sum up to high catalytic activity without compromising stability.
Proton-exchange membrane fuel cells (PEMFCs) are the dominant fuel cell technology for automotive applications, while anion-exchange membrane fuel cells (AEMFCs) are being developed to reduce reliance on platinum-group metals. However, both technologies are still improving, so their environmental comparison should consider prospective progress on both sides. Using the ReCiPe 2016 characterisation method, this study conducts a cradle-to-use life cycle assessment of four 80-kW light-duty vehicle fuel cell systems: PEMFC-refPt, PEMFC-lowPt, AEMFC-PdRu, and AEMFC-FeNi. The cases differ in catalyst type and loading, power density, oxidant supply, efficiency, degradation rate, and stack lifetime. The assessment covers manufacturing, hydrogen use over 8000 hours, and stack replacement. The results show that AEMFCs are not automatically environmentally preferable to PEMFCs. AEMFC-FeNi performs worse than PEMFC-refPt in 12 of 18 midpoint categories due to its low power density, larger active area, higher catalyst loading, and stack replacement burden. While AEMFC-PdRu performs better than PEMFC-refPt in nine midpoint categories, its GWP remains 13.8% higher at 22 226 kg CO2-eq. PEMFC-lowPt gives the lowest cradle-to-use GWP (18 001 kg CO2-eq) and the lowest endpoint damage score (1651 points). Sensitivity analysis shows that the load factor and hydrogen source strongly affect GWP, while catalyst loading and degradation rate have smaller effects. To match PEMFC-refPt, AEMFC-FeNi requires at least 55% efficiency, around 6000 h lifetime, and power density close to 1900 mW cm-2. Therefore, the environmental benefit of AEMFCs depends less on catalyst metal substitution alone and more on whether high power density, long lifetime, and efficiency comparable to PEMFCs be achieved simultaneously.
Membrane-directed hydroxide flux enables concurrent Murakami's reagent synthesis and energy-efficient hydrogen fuel production.
