Developing an effective and efficient recycling process for marine debris (MD) is one of the most urgent issues to maintain environmental sustainability on Earth. However, restricted storage ...capacities and secondary pollution (e.g., microbial adhesion, putrefaction) limit the proper MD recycling. Here, we proposed a complete eco-friendly low-temperature MD pulverizing system that utilizes excessive liquefied natural gas (LNG) cold energy (LCE) in an LNG propulsion ship to improve the efficiency and effectiveness of MD recycling. The prototype design of the low-temperature pulverization (LTP) system showed that consumable refrigerant (liquid nitrogen) up to 2831 kg per hour could be substituted. Furthermore, with a 20% ship output, 1250 kg of MD could be treated with 363 kg of additional refrigerant. In addition, LTP systems utilizing LCE could increase the storage capacity by more than 10 times compared to bulk MD while minimizing the required energy consumption. To determine the feasibility of LTP for MD recycling, four types of plastics obtained from actual MD from a coastal area in Busan, Korea were classified and tested.
The development of cost-effective and high-performance electrocatalysts for water oxidation has attracted intense research interest. It was reported recently that the interface between the amorphous ...and crystalline phases plays a significant role in the electrocatalytic activity of transition metal compounds. It was reckoned therefore that an increase in the density of the crystalline-amorphous phase boundary would enhance the electrochemical water oxidation on the catalyst. In this work we develop a new and facile strategy for inducing high density crystalline-amorphous phase boundaries
via
selective fluorination surface doping. This resulted in excellent characteristics of the engineered material for electrochemical water splitting. An initial computational simulation is carried out to design the crystalline-amorphous phase boundary material and an experimental verification follows for demonstration and optimization of the impact of surface doping. We conclude that the engineering of the interface using this facile and cost-effective strategy maximizes the crystalline and amorphous phases of metal-metalloids, which can be used to fabricate low-cost and efficient electrocatalysts for water oxidation.
Crystalline-amorphous phase boundary engineering can be an effective strategy to develop cost-effective and high-performance electrocatalysts for water splitting.
The liver is an important organ and plays major roles in the human body. Because of the lack of liver donors after liver failure and drug-induced liver injury, much research has focused on developing ...liver alternatives and liver in vitro models for transplantation and drug screening. Although numerous studies have been conducted, these systems cannot faithfully mimic the complexity of the liver. Recently, three-dimensional (3D) cell printing technology has emerged as one of a number of innovative technologies that may help to overcome this limitation. However, a great deal of work in developing biomaterials optimized for 3D cell printing-based liver tissue engineering remains. Therefore, in this work, we developed a liver decellularized extracellular matrix (dECM) bioink for 3D cell printing applications and evaluated its characteristics. The liver dECM bioink retained the major ECM components of the liver while cellular components were effectively removed and further exhibited suitable and adjustable properties for 3D cell printing. We further studied printing parameters with the liver dECM bioink to verify the versatility and fidelity of the printing process. Stem cell differentiation and HepG2 cell functions in the liver dECM bioink in comparison to those of commercial collagen bioink were also evaluated, and the liver dECM bioink was found to induce stem cell differentiation and enhance HepG2 cell function. Consequently, the results demonstrate that the proposed liver dECM bioink is a promising bioink candidate for 3D cell printing-based liver tissue engineering.
Though highly promising as powerful gas sensors, oxide semiconductor chemiresistors have low surface reactivity, which limits their selectivity, sensitivity, and reaction kinetics, particularly at ...room temperature (RT) operation. It is proposed that a hybrid design involving the nanostructuring of oxides and passivation with selective gas filtration layers can potentially overcome the issues with surface activity. Herein, unique bi‐stacked heterogeneous layers are introduced; that is, nanostructured oxides covered by conformal nanoporous gas filters, on ultrahigh‐density nanofiber (NF) yarns via sputter deposition with indium tin oxide (ITO) and subsequent self‐assembly of zeolitic imidazolate framework (ZIF‐8) nanocrystals. The NF yarn composed of ZIF‐8‐coated ITO films can offer heightened surface activity at RT because of high porosity, large surface area, and effective screening of interfering gases. As a case study, the hybrid sensor demonstrated remarkable sensing performances characterized by high NO selectivity, fast response/recovery kinetics (>60‐fold improvement), and large responses (12.8‐fold improvement @ 1 ppm) in comparison with pristine yarn@ITO, especially under highly humid conditions. Molecular modeling reveals an increased penetration ratio of NO over O2 to the ITO surface, indicating that NO oxidation is reliably prevented and that the secondary adsorption sites provided by the ZIF‐8 facilitate the adsorption/desorption of NO, both to and from ITO.
A multifunctional chemiresistive gas sensor composed of nanofiber yarn sputter‐deposited with indium tin oxide (ITO) as a sensing layer is designed, and then coated with zeolitic imidazolate framework (ZIF‐8) for nanofiltration of gas analytes. Through comprehensive sensing experiments and molecular modeling, it is demonstrated that yarn@ITO@ZIF‐8 exhibits highly sensitive and selective sensing properties toward NO at room temperature with accelerated responding speeds.
The clean and sustainable CO
2
reutilization toward products of higher value is of great interest in a background of established environmental concerns and reducing the use of fossil fuels. As ...promising alternative fuels, hydrocarbons are more valuable than CO, alcohols or formate and can be directly used in existing infrastructures with high energy densities. The prominent development of catalysts capable of selectively converting CO
2
into hydrocarbons, from methane to short olefins and long carbon-chains, has been reflected in an expanding volume of exploratory works, which suitably demand interpretive and continuous revision. In the past decades, conventional studies on the thermochemical conversion of CO
2
have consistently unlocked meaningful pathways toward the synthesis of hydrocarbons covering a fairly wide range of molecular weights. Conversely, both electrochemically and photochemically driven reactions have only now started to unveil encouraging results, with an extensive number of critical citations outlining the continuous emergence of very recently published reports. In a field in need of urgent development, the authors provide, in a clear form, a detailed retrospective on benchmark catalysts, pioneering approaches and competitive developments in this subject, mechanistic difficulties, emerging stability issues, and reactor design, while highlighting the latest noteworthy reports. Most importantly, this review highlights the advances toward an increase in the hydrocarbon chain-length in the synthesis of highly competitive alternative fuels. Comparisons of valuable thermochemical, electrochemical and photochemically driven strategies in the conversion of CO
2
to hydrocarbons are expected to serve as guidelines to disclose promising pathways in a field where mechanistic uncertainties remain a bottleneck for determining the product selectivity. The authors summarize leading and inquisitive perspectives with a focus on the viability and practicability of each approach at a larger scale, while tentatively paving the way to stimulate progress in this field.
Comprehensive insight into the thermochemical, photochemical and electrochemical reduction of CO
2
to methane and long-chain hydrocarbons as alternative fuels.
Transition metal dichalcogenides (TMDs) have attracted significant interest as gas‐sensing materials due to their unique crystal structure and surface. However, there are still issues when it comes ...to expanding the types of sensing gases for the TMD gas sensors. To extend gas‐sensing selectivity for the TMD gas sensors in this study, a monolayer (ML) 2D metal–organic framework (MOF) is introduced on top of the PtSe2 gas sensor, thereby tuning the major sensing analyte of PtSe2 from NO2 to H2S. Density functional theory calculations elucidate that the metal species of ML MOFs are attributed to the tuned selectivity of the analytes, based on the difference in binding energies. It is also demonstrated that ML MOF maintained the high responsivity of the pristine PtSe2 even at a low concentration of gas (200 ppb). This is further confirmed through the molecular dynamics simulations, which reveal that the ML feature of the ML MOF is highly essential to preserve the intrinsic ultra‐low limit detection properties of pristine PtSe2.
The monolayer 2D metal–organic framework is introduced to tune the gas‐sensing selectivity of PtSe2, one of the most promising gas‐sensing materials in transition metal dichalcogenides. The tuning mechanism is revealed by density functional theory calculations. The monolayer metal–organic framework also preserves ultra‐low detection limit of PtSe2, and it is elucidated by molecular dynamics simulation.
Edges of 2D transition metal dichalcogenides (TMDs) are well known as highly reactive sites, thus researchers have attempted to maximize the edge site density of 2D TMDs. In this work, metal‐organic ...framework (MOF) templates are introduced to synthesize few‐layered WS2 nanoplates (a lateral dimension of ≈10 nm) confined in Co, N‐doped hollow carbon nanocages (WS2_Co‐N‐HCNCs), for highly sensitive NO2 gas sensors. WS2 precursors are assembled in the surface cavity of Co‐based zeolite imidazole framework (ZIF‐67) and subsequent pyrolysis produced WS2_Co‐N‐HCNCs. During the pyrolysis, the carbonized ZIF‐67 are doped by Co and N elements, and the growth of WS2 is effectively suppressed, creating few‐layered WS2 nanoplates functionalized Co‐N‐HCNCs. The WS2_Co‐N‐HCNCs exhibit outstanding NO2 sensing characteristics at room temperature, in terms of response (48.2% to 5 ppm), selectivity, response and recovery speed, and detection limit (100 ppb). These results are attributed to the enhanced adsorption and desorption kinetics of NO2 on abundant WS2 edges, confined in the gas permeable HCNCs. This work opens up an efficient way for the facile synthesis of edge abundant few‐layered TMDs combined with porous carbon matrix via MOF templating route, for applications relying on highly active sites.
Few‐layered WS2 nanoplates confined in Co, N‐doped hollow carbon nanocages (WS2_Co‐N‐HCNCs) are synthesized using metal‐organic framework (MOF) templating. The porous MOF suppresses the growth of WS2, creating few‐layered WS2 nanoplates in Co‐N‐HCNCs. The WS2_Co‐N‐HCNCs exhibit highly sensitive NO2 sensing characteristics at room temperature, in terms of response, selectivity, response/recovery speed, and detection limits.
We developed perovskite solar cells (PSCs) with a ZnO electron-transporting layer (ETL) of which the surface was passivated with methoxybenzoic acid self-assembled monolayers (SAMs). The ...self-assembled monolayer (SAM) simultaneously improved the photovoltaic performance and device stability. First, the methoxybenzoic acid, which is noncovalently bonded to the methylammonium of the perovskite layer, effectively induced dipole moments; in particular, 3,4,5-trimethoxybenzoic acid (TMBA) gave a larger workfunction shift of ZnO ETL compared with 4-methoxybenzoic acid (MBA) and 3,4-dimethoxybenzoic acid (DMBA) owing to its strong dipole moment and hydrogen-bonding between the methoxy group and ammonium. This effectively enhanced the built-in voltage of the perovskite solar cell (PSC) device, which resulted in an improved electron transfer from the active layer to the ETL and a higher open-circuit voltage. Secondly, the SAM layer controlled the wettability of the perovskite precursor solution on the ZnO ETL and significantly improved the crystalline properties of the perovskite layer. Moreover, the ZnO/SAM ETL remarkably increased the PSC device stability under ambient conditions by preventing the proton transfer reaction between the perovskite layer and the ZnO ETL. As a result, the TMBA-SAM based PSC device achieved a significantly enhanced efficiency of 13.75% compared to 1.44% for the bare ZnO with high long-term stability.
The SAM layer which formed hydrogen-bonding to the methylammonium of the perovskite induced dipole moments at the interface, resulting in energy band bending and increased built-in voltage, and consequently, improved charge transfer of the PSC.
Flexible and stretchable electrochromic supercapacitor systems are widely considered as promising multifunctional energy storage devices that eliminate the need for an external power source. ...Nevertheless, the performance of conventional designs deteriorates significantly as a result of electrode/electrolyte exposure to atmosphere as well as mechanical deformations for the case of flexible systems. In this study, we suggest an all-transparent stretchable electrochromic supercapacitor device with ultrastable performance, which consists of Au/Ag core–shell nanowire-embedded polydimethylsiloxane (PDMS), bistacked WO3 nanotube/PEDOT:PSS, and polyacrylamide (PAAm)-based hydrogel electrolyte. Au/Ag core–shell nanowire-embedded PDMS integrated with PAAm-based hydrogel electrolyte prevents Ag oxidation and dehydration while maintaining ionic and electrical conductivity at high voltage even after 16 days of exposure to ambient conditions and under application of mechanical strains in both tensile and bending conditions. WO3 nanotube/PEDOT:PSS bistacked active materials maintain high electrochemical–electrochromic performance even under mechanical deformations. Maximum specific capacitance of 471.0 F g–1 was obtained with a 92.9% capacity retention even after 50 000 charge–discharge cycles. In addition, high coloration efficiency of 83.9 cm2 C–1 was shown to be due to the dual coloration and pseudocapacitor characteristics of the WO3 nanotube and PEDOT:PSS thin layer.
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