China Jiliang University

Wang Y., Zheng S., Yang W., Zhou R., He Q., Radjenovic P., Dong J., Li S., Zheng J., Yang Z., Attard G., Pan F., Tian Z., Li J.

Understanding the structure and dynamic process of water at the solid–liquid interface is an extremely important topic in surface science, energy science and catalysis1–3. As model catalysts, atomically flat single-crystal electrodes exhibit well-defined surface and electric field properties, and therefore may be used to elucidate the relationship between structure and electrocatalytic activity at the atomic level4,5. Hence, studying interfacial water behaviour on single-crystal surfaces provides a framework for understanding electrocatalysis6,7. However, interfacial water is notoriously difficult to probe owing to interference from bulk water and the complexity of interfacial environments8. Here, we use electrochemical, in situ Raman spectroscopic and computational techniques to investigate the interfacial water on atomically flat Pd single-crystal surfaces. Direct spectral evidence reveals that interfacial water consists of hydrogen-bonded and hydrated Na+ ion water. At hydrogen evolution reaction (HER) potentials, dynamic changes in the structure of interfacial water were observed from a random distribution to an ordered structure due to bias potential and Na+ ion cooperation. Structurally ordered interfacial water facilitated high-efficiency electron transfer across the interface, resulting in higher HER rates. The electrolytes and electrode surface effects on interfacial water were also probed and found to affect water structure. Therefore, through local cation tuning strategies, we anticipate that these results may be generalized to enable ordered interfacial water to improve electrocatalytic reaction rates. Interfacial water consists of hydrogen-bonded water and Na·H2O, its structure changes at hydrogen evolution reaction (HER) potentials, and when structurally ordered it aids interfacial electron transfer, resulting in higher HER rates.

Zhang M., Song G., Gelardi D.L., Huang L., Khan E., Mašek O., Parikh S.J., Ok Y.S.

Removal of nitrogen (N) and phosphorus (P) from water through the use of various sorbents is often considered an economically viable way for supplementing conventional methods. Biochar has been widely studied for its potential adsorption capabilities for soluble N and P, but the performance of different types of biochars can vary widely. In this review, we summarized the adsorption capacities of biochars in removing N (NH4-N and NO3-N) and P (PO4-P) based on the reported data, and discussed the possible mechanisms and influencing factors. In general, the NH4-N adsorption capacity of unmodified biochars is relatively low, at levels of less than 20 mg/g. This adsorption is mainly via ion exchange and/or interactions with oxygen-containing functional groups on biochar surfaces. The affinity is even lower for NO3-N, because of electrostatic repulsion by negatively charged biochar surfaces. Precipitation of PO4-P by metals/metal oxides in biochar is the primary mechanism for PO4-P removal. Biochars modified by metals have a significantly higher capacity to remove NH4-N, NO3-N, and PO4-P than unmodified biochar, due to the change in surface charge and the increase in metal oxides on the biochar surface. Ambient conditions in the aqueous phase, including temperature, pH, and co-existing ions, can significantly alter the adsorption of N and P by biochars, indicating the importance of optimal processing parameters for N and P removal. However, the release of endogenous N and P from biochar to water can impede its performance, and the presence of competing ions in water poses practical challenges for the use of biochar for nutrient removal. This review demonstrates that progress is needed to improve the performance of biochars and overcome challenges before the widespread field application of biochar for N and P removal is realized.

Yang X., Chen Z., Zhao W., Liu C., Qian X., Zhang M., Wei G., Khan E., Hau Ng Y., Sik Ok Y.

• A summary of key recent advances in photocatalytic removal of antibiotics in water. • Special emphasis on the strategies for improving the photodegradation efficiency. • Major challenges and critical perspectives on photocatalysis of antibiotics. Antibiotics are widely present in the environment due to their extensive and long-term use in modern medicine. The presence and dispersal of these compounds in the environment lead to the dissemination of antibiotic residues, thereby seriously threatening human and ecosystem health. Thus, the effective management of antibiotic residues in water and the practical applications of the management methods are long-term matters of contention among academics. Particularly, photocatalysis has attracted extensive interest as it enables the treatment of antibiotic residues in an eco-friendly manner. Considerable progress has been achieved in the implementation of photocatalytic treatment of antibiotic residues in the past few years. Therefore, this review provides a comprehensive overview of the recent developments on this important topic. This review primarily focuses on the application of photocatalysis as a promising solution for the efficient decomposition of antibiotic residues in water. Particular emphasis was laid on improvement and modification strategies, such as augmented light harvesting, improved charge separation, and strengthened interface interaction, all of which enable the design of powerful photocatalysts to enhance the photocatalytic removal of antibiotics.

Hu S., Ding Y., Zhu C.

Increased temperatures caused by global warming threaten agricultural production, as warmer conditions can inhibit plant growth and development or even destroy crops in extreme circumstances. Extensive research over the past several decades has revealed that chloroplasts, the photosynthetic organelles of plants, are highly sensitive to heat stress, which affects a variety of photosynthetic processes including chlorophyll biosynthesis, photochemical reactions, electron transport and CO2 assimilation. Important mechanisms by which plant cells respond to heat stress to protect these photosynthetic organelles have been identified and analyzed. More recent studies have made it clear that chloroplasts play an important role in inducing the expression of nuclear heat-response genes during the heat stress response. In this review, we summarize these important advances in plant-based research and discuss how the sensitivity, responses and signaling roles of chloroplasts contribute to plant heat sensitivity and tolerance.

Liu A., Liang X., Ren X., Guan W., Gao M., Yang Y., Yang Q., Gao L., Li Y., Ma T.

The family of transition metal carbides, nitrides, and carbonitrides (collectively called MXenes) has been a thriving field since the first invention of Ti3C2Tx (MXene) in 2011. MXene is a new type of nanometer 2D sheet material, which exhibits great application potentials in various fields due to its multiple advantages such as high specific surface area, good electrical conductivity, and high mechanical strength. Electrocatalysis is regarded as the core of future clean energy conversion technologies, and MXene-based materials provide inspiration for the design and preparation of electrocatalysts with high activity, high selectivity, and long loading life time. The applications of MXene-based materials in electrocatalysis, including hydrogen evolution reaction, nitrogen reduction reaction, oxygen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, and methanol oxidation reaction are summarized in this review. As a crucial session regarding experiments, the current safer and more environmentally friendly preparation methods of MXene are also discussed. Focusing on the materials design and enhancement methods, the key challenges and opportunities for MXene-based materials as a next-generation platform in both fundamental research and practical electrocatalysis applications are presented. This account serves to promote future efforts toward the development of MXenes and related materials in the electrocatalysis applications.

Han L., Huang H., Fu X., Li J., Yang Z., Liu X., Pan L., Xu M.

With the development of flexible wearable electronic devices, energy storage equipment like supercapacitor with high energy density, good mechanical properties and safety has attracted more and more attention. However, the currently existing energy storage materials normally suffer from several drawbacks, such as poor flexibility, hidden danger, toxicity and especially low energy density, limiting their practical applications. Expanding the voltage window by employing the hydrogel electrolyte is regarded as an effective method to improve the energy density of supercapacitor. Herein, we employ a zwitterionic natural polymer hydrogel with excellent mechanical strength and flexibility as electrolyte to assemble a solid-state zinc-ion hybrid supercapacitor (H-ZHS) with Zn foil and activated carbon electrode. The H-ZHS exhibits an amazingly wide and stable voltage window of 2.4 V, high maximum energy density of 286.6 Wh kg−1 at the power density of 220 W kg−1 and superior capacity retention of 95.4% after 2000 cycles at 2 A g−1 calculated based on mass of activated carbon electrode. The strategy in this work should provide a new insight in exploring zinc-ion hybrid supercapacitor with high energy density for flexible wearable electronic devices.

Liu A., Gao M., Ren X., Meng F., Yang Y., Gao L., Yang Q., Ma T.

As a promising and important carbon source, utilization of carbon dioxide (CO2) can effectively solve the energy crisis caused by fossil resource consumption and the environmental problems arising from the emission of CO2.

Sun C., Chen T., Huang Q., Zhan M., Li X., Yan J.

Environment-friendly and low-cost catalysts are important for persulfate based advanced oxidation processes. In this study, we reported a CO2-activated biochar (AC) as a low-cost and efficient catalyst for persulfate (PS) activation and the degradation of phenol and chlorophenols. The AC950 showed the best catalytic performance for PS with an oxidant utility of 0.5 mol/mol oxidant/h/g with an activation energy of 15.86 kJ/mol owing to its large surface area, rich surface defects, and well-modified oxygen functional groups. In contrast to a radical-based mechanism, this novel biochar/persulfate system works through a non-radical mechanism that includes singlet state oxygen generation and an electron transfer reaction pathway. The major degradation intermediate of the phenolic pollutant was identified to be benzoquinone; moreover, amongst chlorophenols, the para-chlorine substituent was the first to degrade. The durability of the catalyst was low, it was deactivated primarily because of the oxidation of the carbon surface, and thermal regeneration was determined to be efficient for its recovery. Furthermore, HCO3− and HPO42− were found to considerably inhibit the performance of the catalytic oxidation system.

Wang Y., Han Z., Du Y., Qin J.

Abstract Toroidal dipole (TD) with weak coupling to the electromagnetic fields offers tremendous potential for advanced design of photonic devices. However, the excitation of high quality (Q) factor TD resonances in these devices is challenging. Here, we investigate ultrahigh-Q factor TD resonances at terahertz frequencies arising from a distortion of symmetry-protected bound states in the continuum (BIC) in all-dielectric metasurface consisting of an array of high-index tetramer clusters. By elaborately arranging the cylinders forming an asymmetric cluster, two distinct TD resonances governed by BIC are excited and identified. One is distinguished as intracluster TD mode that occurs in the interior of tetramer cluster, and the other one is intercluster TD mode that arises from the two neighboring clusters. Such TD resonances can be turned into ultrahigh-Q leaky resonances by controlling the asymmetry of cluster. The low-loss TD resonances with extremely narrow linewidth are very sensitive to the change in the refractive index of the surrounding media, achieving ultrahigh sensitivity level of 489 GHz/RIU. These findings will open up an avenue to develop ultrasensitive photonic sensor in the terahertz regime.

Han Y., Liu B., Xiao Z., Zhang W., Wang X., Pan G., Xia Y., Xia X., Tu J.

Lithium (Li) metal is considered as one of the most promising anode materials for next-generation high-energy-density storage systems. However, the practical application of Li metal anode is hindered by interfacial instability and air instability due to the highly reactivity of Li metal. Unstable interface in Li metal batteries (LMBs) directly dictates Li dendrite growth, “dead Li” and low Coulombic efficiency, resulting in inferior electrochemical performance of LMBs and even safety issues. In addition, its sensitivity to ambient air leads to the severe corrosion of Li metal anode, high requirements of production and storage, and increased manufacturing cost. Plenty of efforts in recent years have overcome many bottlenecks in these fields and hastened the practical applications of high-energy-density LMBs. In this review, we focus on emerging methods of these two aspects to fulfill a stable and low cost electrode. In this perspective, design artificial solid electrolyte interphase (SEI) layers, construct three-dimensional conductive current collectors, optimize electrolytes, employ solid-state electrolytes, and modify separators are summarized to be propitious to ameliorate interfacial stability. Meanwhile, ex situ/in situ formed protective layers are highlighted in favor of heightening air stability. Finally, several possible directions for the future research on advanced Li metal anode are addressed.