Xi'an University of Architecture and Technology

Dye-sensitized solar cells (DSSCs) have attracted widespread attention in recent years as potential cost-effective alternatives to silicon-based and thin-film solar cells. Within typical DSSCs, the counter electrode (CE) is vital to collect electrons from the external circuit and catalyze the I3- reduction in the electrolyte. Careful design of the CEs can improve the catalytic activity and chemical stability associated with the liquid redox electrolyte used in most cells. In this Progress Report, advances made by our groups in the development of CEs for DSSCs are reviewed, highlighting important contributions that promise low-cost, efficient, and robust DSSC systems. Specifically, we focus on the design of novel Pt-free CE catalytic materials, including design ideas, fabrication approaches, characterization techniques, first-principle density functional theory (DFT) calculations, ab-initio Car-Parrinello molecular dynamics (CPMD) simulations, and stability evaluations, that serve as practical alternatives to conventional noble metal Pt electrodes. We stress the merits and demerits of well-designed Pt-free CEs, such as carbon materials, conductive polymers, transition metal compounds (TMCs) and their corresponding hybrids. Also, the prospects and challenges of alternative Pt catalysts for their applications in new-type DSSCs and other catalytic fields are discussed.

In the last decade, interfacial solar steam generation (ISSG), powered by natural sunlight garnered significant attention due to its great potential for low-cost and environmentally friendly clean water production in alignment with the global decarbonization efforts. This review aims to share the knowledge and engage with a broader readership about the current progress of ISSG technology and the facing challenges to promote further advancements toward practical applications. The first part of this review assesses the current strategies for enhancing the energy efficiency of ISSG systems, including optimizing light absorption, reducing energy losses, harvesting additional energy, and lowering evaporation enthalpy. Subsequently, the current challenges faced by ISSG technologies, notably salt accumulation and bio-fouling issues in practical applications, are elucidated and contemporary methods are discussed to overcome these challenges. In the end, potential applications of ISSG, ranging from initial seawater desalination and industrial wastewater purification to power generation, sterilization, soil remediation, and innovative concept of solar sea farm, are introduced, highlighting the promising potential of ISSG technology in contributing to sustainable and environmentally conscious practices. Based on the review and in-depth understanding of these aspects, the future research focuses are proposed to address potential issues in both fundamental research and practical applications.

New-generation integrated devices based on dye-sensitized and perovskite solar cells for energy harvesting and storage are significantly important for self-powering systems and portable/wearable electronics.

). With high adsorption capacity and excellent stability, MOF-808 shows great potential for the sustainable removal of radioiodine.

Abstract Rechargeable aqueous zinc‐ion batteries (AZIBs) have attracted extensive attention and are considered to be promising energy storage devices, owing to their low cost, eco‐friendliness, and high security. However, insufficient energy density has become the bottleneck for practical applications, which is greatly influenced by their cathodes and makes the exploration of high‐performance cathodes still a great challenge. This review underscores the recent advances in the rational design of advanced cathodes for AZIBs. The review starts with a brief summary and evaluation of cathode material systems, as well as the introduction of proposed storage mechanisms. Then, fundamental problems associated with ion and electron transport behaviors inside the electrode will be pointed out and followed by potential solutions, aiming to reveal the correlation between cathode architecture design and efficient transport kinetics through structural engineering. Afterward, the structural engineering for designing advanced cathodes, including interlayer intercalation, doping effects, defect engineering, surface coatings, composite formation, and morphology control, are summarized and discussed from the view of experimental and theoretical results. Finally, the critical research challenges and future perspectives on advanced cathode materials as well as the potential developing directions of AZIBs are also given.

The collapse potential, mineralogy, microstructure, and particle morphology of a loess from the Loess Plateau, China, were characterized by double oedometer testing, X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy, and image analysis to elucidate the origin of its collapse behavior. Results show that the loess is highly collapsible with a maximum collapse index of 6.7% at a vertical stress of ∼200 kPa. The deposit contains both nonclay (i.e., quartz, albite, muscovite, and calcite) and clay (i.e., two chlorites) minerals. Microstructural, chemical, and image analyses indicate that interparticle calcite and clay cementation and silt particle morphology render the intact soil a metastable structure. Wetting-induced collapse is attributed to both primary and secondary microstructure features. The former is the abundance of weakly cemented, unsaturated, porous pure clay and clay–silt mixture aggregates whose slaking upon wetting initiates the overall structural collapse, while the latter consists of high porosity, unstable particle contacts, and clay coating on silt particles that act synergistically to augment the collapse. A conceptual microstructural model of a four-tiered hierarchy (i.e., primary clay and silt particles, clay aggregates and clay-coated silt particles, clay–silt mixture aggregates, and cemented aggregate matrix) is proposed to represent its structural characteristics and to account for its high collapsibility.

Comparative study of the photocatalytic performance for the degradation of different by ZnIn ₂ S ₄ based on the adsorption of dyes, the active species and the degradation pathway.

Abstract Two-dimensional membranes attract extensive interest due to the anomalous transport phenomena; however, the ion separation performance is below the theoretical prediction. The stabilization of d-spacing is a key step for enhancing ion selectivity. Here, we demonstrate a strategy for stabilizing the Ti 3 C 2 T x laminar architecture by alginate hydrogel pillars. After pillared by Ca-alginate, the nanochannel diameters are effectively fixed at 7.4 ± 0.2 Å, and the membrane presents a permeation cutoff and an outstanding sieving property towards valent cations. When applied for acid recovery, the outstanding H + /Fe 2+ selectivity makes the membrane a promising substitution for traditional ion-exchange membranes. Moreover, the ultrathin Mn-alginate pillared membrane with identical d-spacing exhibits 100% Na 2 SO 4 rejection with high water permeance, which is superior to the state-of-the-art nanofiltration membranes. Building on these findings, we demonstrate an efficient method to tune the ion selectivity and introduce a new perspective for energy- and environment-related applications.

A three dimensional problem can be approximated by either a two-dimensional or one-dimensional case, but some information will be lost. To reveal the lost information due to the lower dimensional approach, two-scale mathematics is needed. Generally one scale is established by usage where traditional calculus works, and the other scale is for revealing the lost information where the continuum assumption might be forbidden, and fractional calculus or fractal calculus has to be used. The two-scale transform can approximately convert the fractional calculus into its traditional partner, making the two-scale thermodynamics much promising.

The development of new, appealing metal-free photocatalysts is of great significance for photocatalytic hydrogen evolution. Herein, an electrostatic self-assembly method to form a unique core–shell architecture of a colloid of carbon spheres with graphitic carbon nitride (g-C 3 N 4 ) has been developed by a one-step chemical solution route. The chemical protonation of g-C 3 N 4 solids with strong oxidizing acids (such as HNO 3 ) is an efficient pathway toward the sol procedure of stable carbon nitride colloids, which can cover the surface of carbon spheres via electrostatic adsorption. On account of the unique polymeric matrix of g-C 3 N 4 and reversible hydrogen bonding, the carbon@g-C 3 N 4 derived from the sol solution showed high mechanical stability with broadened light absorption and enhanced conductivity for charge transport. Thus, the carbon@g-C 3 N 4 core–shell structure exhibited remarkably enhanced photoelectrochemical performance. This polymer system is envisaged to hybridize with desirable functionalities (such as carbon nanorods) to form unique architectures for various applications.

Any physical laws are scale-dependent, the same phenomenon might lead to debating theories if observed using different scales. The two-scale thermodynamics observes the same phenomenon using two different scales, one scale is generally used in the conventional continuum mechanics, and the other scale can reveal the hidden truth beyond the continuum assumption, and fractal calculus has to be adopted to establish governing equations. Here basic properties of fractal calculus are elucidated, and the relationship between the fractal calculus and traditional calculus is revealed using the two-scale transform, fractal variational principles are discussed for 1-D fluid mechanics. Additionally planet distribution in the fractal solar system, dark energy in the fractal space, and a fractal ageing model are also discussed.

Asthma, rhinitis and eczema (allergic or non-allergic) have increased throughout the world during the last decades, especially among children. Changes in the indoor environment are suspected to be important causes. China has experienced a dramatic change in indoor environmental exposures during the past two decades. However, such changes and their associations with children’s asthma and other health aspects have not been thoroughly studied. China, Children, Homes, Health (CCHH), Phase I, was a cross-sectional questionnaire survey of 48219 children 1–8 years old in 10 Chinese cities during 2010–2012. The questionnaire includes the International Study of Asthma and Allergies in Childhood (ISAAC) core health questions and additional questions regarding housing, life habits and outdoor environment. In health analyses, children aged 3–6 years old were included. The prevalences of doctor diagnosed asthma varied from 1.7% to 9.8% (mean 6.8%), a large increase from 0.91% in 1999 and 1.50% in 2000. The prevalence of wheeze, rhinitis and atopic eczema (last 12 months) varied from 13.9% to 23.7%, 24.0% to 50.8% and 4.8% to 15.8%, respectively. Taiyuan had the lowest prevalences of all illnesses and Shanghai the highest, except for wheezewhere the highest value was for Urumqi. We found (1) no obvious association between disease prevalences and ambient PM 10 concentrations and (2) higher prevalences of disease in humid climates with hot summers and cold winters, but with no centrally heated buildings. Associations between the diseases and economic status as indexed by Gross Domestic Product (GDP) requires further study.

A 2D zinc cobaltite nanosheet is rationally designed and directly utilized as a binder-free electrode for SC with extraordinary high energy density.

Urban agglomeration, an established urban spatial pattern, contributes to the spatial association and dependence of city-level CO2 emission distribution while boosting regional economic growth. Exploring this spatial association and dependence is conducive to the implementation of effective and coordinated policies for regional level CO2 reduction. This study calculated CO2 emissions from 2005–2016 in the Chengdu-Chongqing urban agglomeration with the IPAT model, and empirically explored the spatial structure pattern and association effect of CO2 across the area leveraged by the social network analysis. The findings revealed the following: (1) The spatial structure of CO2 emission in the area is a complex network pattern, and in the sample period, the CO2 emission association relations increased steadily and the network stabilization remains strengthened; (2) the centrality of the cities in this area can be categorized into three classes: Chengdu and Chongqing are defined as the first class, the second class covers Deyang, Mianyang, Yibin, and Nanchong, and the third class includes Zigong, Suining, Meishan, and Guangan—the number of cities in this class is on the rise; (3) the network is divided into four subgroups: the area around Chengdu, south Sichuan, northeast Sichuan, and west Chongqing where the spillover effect of CO2 is greatest; and (4) the higher density of the global network of CO2 emission considerably reduces regional emission intensity and narrows the differences among regions. Individual networks with higher centrality are also found to have lower emission intensity.

Abstract Producing electrolytes with high ionic conductivity has been a critical challenge in the progressive development of solid oxide fuel cells (SOFCs) for practical applications. The conventional methodology uses the ion doping method to develop electrolyte materials, e.g., samarium-doped ceria (SDC) and yttrium-stabilized zirconia (YSZ), but challenges remain. In the present work, we introduce a logical design of non-stoichiometric CeO 2-δ based on non-doped ceria with a focus on the surface properties of the particles. The CeO 2−δ reached an ionic conductivity of 0.1 S/cm and was used as the electrolyte in a fuel cell, resulting in a remarkable power output of 660 mW/cm 2 at 550 °C. Scanning transmission electron microscopy (STEM) combined with electron energy-loss spectroscopy (EELS) clearly clarified that a surface buried layer on the order of a few nanometers was composed of Ce 3+ on ceria particles to form a CeO 2−δ @CeO 2 core–shell heterostructure. The oxygen deficient layer on the surface provided ionic transport pathways. Simultaneously, band energy alignment is proposed to address the short circuiting issue. This work provides a simple and feasible methodology beyond common structural (bulk) doping to produce sufficient ionic conductivity. This work also demonstrates a new approach to progress from material fundamentals to an advanced low-temperature SOFC technology.

A comprehensive experimental evaluation using different techniques can provide a systematical assessment for CE stability of DSSCs from different angles.

Alkali-activated slag concrete (AASC) is a new green building material. The amount of CO2 produced by AASC is 1/5th of that produced by ordinary Portland cement concrete (OPCC). In addition, AASC promotes the reuse of slag and other wastes and saves resources. Furthermore, the scope of use of slag has been expanded. The progress of the research on the hydration characteristics, microstructure, interfacial transition zone, and pore structure of AASC based on the relevant literatures was analyzed and summarized in this study. The influences of the slag composition, the type and dosage of the alkali activator, and the curing conditions on the hydration characteristics and the microstructure of the AASC were discussed. Relatively few research results on the microstructure of AASC are available, and the relevant conclusions are not completely consistent. Moreover, there are many constraints on the development of AASC (e.g., complex composition of raw materials of slag, large shrinkage deformation, and low fluidity). Therefore, further research is required.

Thousands of different nanoparticles (NPs) involve in our daily life with various origins from food, cosmetics, drugs, etc. It is believed that decreasing the size of materials up to nanometer levels can facilitate their unfavorable absorption since they can pass the natural barriers of live tissues and organs even, they can go across the relatively impermeable membranes. The interaction of these NPs with the biological environment disturbs the natural functions of cells and its components and cause health issues. In the lack of the detailed and comprehensive standard protocols about the toxicity of NPs materials, their control, and effects, this review study focuses on the current research literature about the related factors in toxicity of NPs such as size, concentration, etc. with an emphasis on metal and metal oxide nanoparticles. The goal of the study is to highlight their potential hazard and the advancement of green non-cytotoxic nanomaterials with safe threshold dose levels to resolve the toxicity issues. This study supports the NPs design along with minimizing the adverse effects of nanoparticles especially those used in biological treatments.

We report a confined proton transportation in the CeO2/CeO2−δ core–shell structure to build up proton shuttles, leading to a super proton conductivity of 0.16 S cm–1 for the electrolyte and advanced fuel cell performance, 697 mW cm–2 at 520 °C. The semiconductor nature of the CeO2 (i-type) core and the CeO2−δ (n-type) shell reveals a unique proton transport mechanism based on the charged layers formed at the interface of the CeO2−δ/CeO2 heterostructure. Two key factors of this structure confine proton transport to the particle surface. The first is the high concentration of oxygen vacancies in the surface layer, which benefits proton conduction. The second is a depletion region created by the core–shell interface that allows proton migration only on the surface layer rather than into the bulk CeO2. The constrained surface region of the CeO2−δ builds up continuous proton shuttles. This work presents a new methodology and understanding for proton transport in general oxides and a new generation proton ceramic fuel cells.

This paper gives the simplest approach to the cubic-quintic Duffing equation (M.S.H. Chowdhury et al., Results in Physics 7(2017): 3962–3967), providing an extremely fast and relatively accurate estimation of the frequency of a nonlinear conservative oscillator. Keywords: Frequency formulation, Duffing oscillator, Nonlinear conservative oscillator