The reactivity of metallurgical coke is a key contributory factor to its integrity in the ironmaking blast furnace. Herein, the factors that influence the CO2 gasification reactivity of individual coke inert maceral derived components (IMDC) and reactive maceral derived components (RMDC) were examined, including: Parent inertinite types, degree of microtextural anisotropy, accessibility of the IMDC; and ash chemistry. Individual IMDC and RMDC components were formed by coking inertinite group concentrates (IC) and vitrinite group concentrates (VC), respectively. Cokes were also formed from head coals and by using different proportions of IC and VC in the coking blend. Coke lump and intrinsic gasification kinetics were compared for each case, where "intrinsic" refers to the gasification behaviour of powdered samples. The most influential factors on which the reaction rate was dependent were distinctly different between lump and powdered samples. The degree of isotropy of the carbon structure was the most important parameter controlling coke lump gasification kinetics with CO2 at 1 100 degrees C, followed by the basicity index of head coal. Conversely, intrinsic reactivity was closely correlated with microporosity. Importantly, the isotropy of the carbon structure was not found to be a critical parameter controlling the intrinsic gasification kinetics up to the 40% carbon conversion point. These results suggest that in the lump form where gas diffusion limits the reaction rate, carbon structure and catalytic effect of coke minerals play the dominant role in coke gasification. Such behaviour leads to a selective reaction of gas with IMDC in coke lumps due to the isotropy of carbon and greater association with minerals.
Lead-free copper halide light-emitting diodes (LEDs) have emerged as a promising alternative to perovskite LEDs, particularly in the context of environmental challenges. This study investigates the performance enhancement of cesium copper iodide (CsCu2I3) LEDs through device engineering techniques, including precursor coevaporation, cohost engineering, and process optimization. Coevaporation of cesium iodide (CsI) and copper iodide (CuI) offers better control over film composition compared with conventional techniques such as wet chemical synthesis or solution processing, thereby simplifying the device fabrication. This dry deposition method minimizes issues related to solvent residues and simplifies the fabrication process. Incorporating the cohosts, 1,3,5-tri(m-pyridin-3-ylphenyl)benzene (TmPyPB) and 4,4',4-tris(carbazol-9-yl)triphenylamine (TcTa), in the emissive layer improves charge balancing and film formation, enhancing overall performance. The optimal results were achieved with a 6:1 cohost ratio and a 2.5% CsCu2I3 doping ratio, resulting in a maximum luminance of 6278 cd/m2, a current efficiency (CE) of 4.14 cd/A, a power efficiency (PE) of 1.22 lm/W, and an external quantum efficiency (EQE) of 1.44%. The substrate temperature of 60 degrees C further influenced device performance, with almost 50% improvement in EQE, reaching 2.14%. The device improvements are a result of the nanoscale control over film morphology, composition, and interface quality enabled using controlled coevaporation. Overall, this study highlights the potential of coevaporation of precursors with cohosts and the benefits of substrate temperature in fabricating high-performance and stable CsCu2I3-based LEDs.
The hydrogen evolution reaction (HER) is a highly effective and environmentally sustainable approach for hydrogen generation enabled by electrocatalysts. In this study, NiCo2S4-based nanoflakes grown on Ni foam (NCS NF) were synthesized using a two-step hydrothermal method, involving the sulfidation of a NiCo precursor with Na2S. The resulting material, characterized by a nanoflake morphology and a cubic thiospinel crystal structure, provides an enhanced active surface area, facilitating efficient H+ adsorption and promoting HER kinetics. Electrochemical testing reveals that NCS NF achieves a current density of 10 mA cm-2 at an overpotential of 106 mV in an alkaline electrolyte and 118 mV in a simulated seawater electrolyte, with corresponding Tafel slopes of 94 and 116 mV dec-1, respectively. Notably, the material exhibits stable HER activity in simulated seawater for up to 24 h with minimal degradation. These results demonstrate NCS NF as a highly efficient electrocatalyst for seawater splitting, presenting a promising candidate for large-scale hydrogen production.
Earth-based 3D printed concrete (3DPC) was developed using soil as an alternative to fine aggregates. Locally sourced excavated soil with 4% clay content was used to replace 30-50% of natural sand by weight, as a partial replacement and as an additive. The effect of soil inclusion on the fresh and hardened properties of 3DPC was analyzed. The inclusion of soil led to a reduction of up to 15% in the flow value required for printing and increased open time by 13-60% compared to the control mix. Both extrudability and buildability improved, enabling crack-free printing of more than 30 layers. Isothermal calorimetry showed accelerated hydration, correlating with faster structuration and extended open time. Green strength results showed that soil inclusion delayed the onset of cracks by 30-50%. Compressive strength and bond load values for printed specimens at 28 days showed a reduction of 11-58% and 3-10%, respectively.
The challenges in direct methanol fuel cells (DMFCs) arise from using traditional noble metal anode catalysts, which result in unwanted CO2 emissions. Developing single-atom catalysts (SACs) with high metal loading is crucial for partial methanol oxidation to formate while reducing CO2 emissions. However, this faces difficulties like sintering and CO poisoning of single atoms (SAs) during methanol oxidation reaction (MOR). Though using support vacancies to stabilize metal atoms shows promise for SAC synthesis, cation vacancy defects, especially for methanol oxidation, have received little attention. Here, we have prepared Pt-SA on a Ni(OH)(2)/C support with abundant Ni vacancies (Pt-SA-Ni(OH)(2)/C-V-Ni) as an anode catalyst. The DMFC with this catalyst provides outstanding results of 613.83 mA cm(-2) current and 79.5 mW cm(-2) power densities at the potential of 0.63 V with 99.63% Faraday efficiency for formate production at 70 degrees C, with a minimum amount of CO2 emissions. Pt atoms on V-Ni drive methanol adsorption and CO detoxification, enhancing partial methanol oxidation to formate. DFT further confirmed that methanol favorably forms formate instead of CO2 in Pt-SA-Ni(OH)(2)/C-V-Ni due to a lower energy barrier (1.08 eV) for OCH conversion to HCOOH. This study provides a way for developing high-performance, CO2-free SA-based anode catalysts for DMFCs.
