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- Highly Efficient and Stable Saline Water Electrolysis Enabled by Self‐Supported Nickel‐Iron Phosphosulfide Nanotubes With Heterointerfaces and Under‐Coordinated Metal Active SitesPublication . Yu, Zhipeng; Li, Yifan; Martin‐Diaconescu, Vlad; Simonelli, Laura; Ruiz Esquius, Jonathan; Amorim, Isilda; Araujo, Ana; Meng, Lijian; Faria, Joaquim Luis; Liu, LifengDirect seawater electrolysis is proposed as a potential low-cost approach to green hydrogen production, taking advantage of the vastly available seawater and large-scale offshore renewable energy being deployed. However, developing efficient, earth-abundant electrocatalysts that can survive under harsh corrosive conditions for a long time is still a significant technical challenge. Herein, the fabrication of a self-supported nickel-iron phosphosulfide (NiFeSP) nanotube array electrode through a two-step sulfurization/phosphorization approach is reported. The as-obtained NiFeSP nanotubes comprise abundant NiFeS/NiFeP heterointerfaces and under-coordinated metal sites, exhibiting outstanding activity and durability for the hydrogen and oxygen evolution reactions (HER and OER) in simulated alkaline-seawater solution (KOH + NaCl), with an overpotential of 380 (HER) and 260 mV (OER) at 500 mA cm-2 and outstanding durability of 1000 h. Theoretical calculations support the observed outstanding performance, showing that the heterointerface and under-coordinated metal sites synergistically lower the energy barrier of the rate-determining step reactions. The NiFeSP electrode also shows good catalytic performance for the urea oxidation reaction (UOR). By coupling UOR with HER, the bifunctional NiFeSP electrode pair can efficiently catalyze the overall urea-mediated alkaline-saline water electrolysis at 500 mA cm-2 under 1.938 V for 1000 h without notable performance degradation.
- Lithium–copper alloy embedded in 3D porous copper foam with enhanced electrochemical performance toward lithium metal batteriesPublication . Lu, Ziyu; Tai, Zhixin; Yu, Zhipeng; LaGrow, Alec P.; Bondarchuk, Oleksandr; Sousa, Juliana P.S.; Meng, Lijian; Peng, Zhijian; Liu, LifengSuppressing dendrite growth and accommodating volume change, among others, are the main challenges for lithium (Li) metal anode to be used in rechargeable Li batteries. The commercial macroporous copper (Cu) foam current collector may only tackle these challenges to a little extent, and it is usually unable to provide sufficient Li nucleation sites, leading to rapidly increased polarization and unstable cycling performance. Herein, we report a three-dimensional composite anode comprising Li–Cu alloy melt-cast on a commercial Cu foam (CF) current collector (Li–Cu/CF), which can be converted to a unique architecture consisting of Li metal supported by an interconnected CuLix alloy nanowire network formed because of the phase separation, when the molten Li–Cu alloy cools down and gets solidified. Compared to the bare Li foil, the Li–Cu/CF anode shows a smaller polarization and better cycle stability in the carbonate electrolyte at various current densities ranging from 1 to 5 mA/cm2 and is free from dendrite growth upon repeated Li plating/stripping. This can be attributed to the low Li nucleation overpotential and high Coulombic efficiency (96%) during Li plating on and stripping from the thus-obtained hierarchically structured CF collector, as well as the higher proportion of Li2O relative to LiF in the solid-electrolyte interphase layer. Moreover, when assembled in a full cell paired with the LiFePO4 cathode, the Li–Cu/CF anode also exhibits much better rate capability and cycle performance than the bare Li foil. Our work provides a new convenient approach to construct a dendrite-free Li metal anode that can be potentially deployed in the next-generation high energy density rechargeable Li batteries.
- A review on the progress of optoelectronic devices based on TiO2 thin films and nanomaterialsPublication . Ge, Shunhao; Sang, Dandan; Zou, Liangrui; Yao, Yu; Zhou, Chuandong; Fu, Hailong; Xi, Hongzhu; Fan, Jianchao; Meng, Lijian; Wang, CongTitanium dioxide (TiO2) is a kind of wide-bandgap semiconductor. Nano-TiO2 devices exhibit size-dependent and novel photoelectric performance due to their quantum limiting effect, high absorption coefficient, high surface-volume ratio, adjustable band gap, etc. Due to their excellent electronic performance, abundant presence, and high cost performance, they are widely used in various application fields such as memory, sensors, and photodiodes. This article provides an overview of the most recent developments in the application of nanostructured TiO2-based optoelectronic devices. Various complex devices are considered, such as sensors, photodetectors, light-emitting diodes (LEDs), storage applications, and field-effect transistors (FETs). This review of recent discoveries in TiO2-based optoelectronic devices, along with summary reviews and predictions, has important implications for the development of transitional metal oxides in optoelectronic applications for researchers.
- Guest Editorial for the special issue covering the selected papers from ANM2022Publication . Meng, Lijian(Excerto do editorial) Humans are highly concerned about their health related to pollution, even at the peak of technology advance. Alternative energy is therefore linked to low carbon renewable energy source with zero carbon emission. Due to its high energy content per unit of weight, hydrogen energy falls in this category and is therefore in high industrial demand. However, the challenge is to replace its production from fossil fuels with new technologies including water electrolysis. Storage is another difficultly facing in Hydrogen energy research. Knowing the bright side of Hydrogen technology, intense research is going on globally to establish hydrogen as potential renewable energy.
- A Review on the Progress of Optoelectronic Devices Based on TiO2 Thin Films and NanomaterialsPublication . Ge, Shunhao; Sang, Dandan; Zou, Liangrui; Yao, Yu; Zhou, Chuandong; Fu, Hailong; Xi, Hongzhu; Fan, Jianchao; Meng, Lijian; Wang, CongTitanium dioxide (TiO2) is a kind of wide-bandgap semiconductor. Nano-TiO2 devices exhibit size-dependent and novel photoelectric performance due to their quantum limiting effect, high absorption coefficient, high surface-volume ratio, adjustable band gap, etc. Due to their excellent electronic performance, abundant presence, and high cost performance, they are widely used in various application fields such as memory, sensors, and photodiodes. This article provides an overview of the most recent developments in the application of nanostructured TiO2-based optoelectronic devices. Various complex devices are considered, such as sensors, photodetectors, light-emitting diodes (LEDs), storage applications, and field-effect transistors (FETs). This review of recent discoveries in TiO2-based optoelectronic devices, along with summary reviews and predictions, has important implications for the development of transitional metal oxides in optoelectronic applications for researchers.
- Inclined Substrate Deposition of Nanostructured TiO2 Thin Films for DSSC ApplicationPublication . Meng, Lijian; Yang, TaoNanostructured TiO2 films were deposited onto Indium Tin Oxide (ITO) and glass substrates by dc reactive magnetron sputtering at different substrate inclination angles. The structural and optical properties of the deposited films were studied by X-ray diffraction, scanning electron microscopy and UV–Vis spectrophotometer, respectively. Dye-sensitized solar cells (DSSC) were assembled using these TiO2 films as photoelectrodes and the effect of the substrate inclination angle in the preparing process of TiO2 films on the DSSC conversion efficiency was studied.
- Iridium–Iron Diatomic Active Sites for Efficient Bifunctional Oxygen ElectrocatalysisPublication . Yu, Zhipeng; Si, Chaowei; LaGrow, Alec P.; Tai, Zhixin; Caliebe, Wolfgang A.; Tayal, Akhil; Sampaio, Maria J.; Sousa, Juliana P. S.; Amorim, Isilda; Araujo, Ana; Meng, Lijian; Faria, Joaquim L.; Xu, Junyuan; Li, Bo; Liu, LifengDiatomic catalysts, particularly those with heteronuclear active sites, have recently attracted considerable attention for their advantages over single-atom catalysts in reactions involving multielectron transfers. Herein, we report bimetallic iridium−iron diatomic catalysts (IrFe−N−C) derived from metal−organic frameworks in a facile wet chemical synthesis followed by postpyrolysis. We use various advanced characterization techniques to comprehensively confirm the atomic dispersion of Ir and Fe on the nitrogen-doped carbon support and the presence of atomic pairs. The asobtained IrFe−N−C shows substantially higher electrocatalytic performance for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) when compared to the single-atom counterparts (i.e., Ir−N−C and Fe−N−C), revealing favorable bifunctionality. Consequently, IrFe−N−C is used as an air cathode in zinc− air batteries, which display much better performance than the batteries containing commercial Pt/C + RuO2 benchmark catalysts. Our synchrotron-based X-ray absorption spectroscopy experiments and density functional theory (DFT) calculations suggest that the IrFe dual atoms presumably exist in an IrFeN6 configuration where both Ir and Fe coordinates with four N atoms and two N atoms are shared by the IrN4 and FeN4 moieties. Furthermore, the Fe site contributes mainly to the ORR, while the Ir site plays a more important role in the OER. The dual-atom sites work synergistically, reducing the energy barrier of the rate-determining step and eventually boosting the reversible oxygen electrocatalysis. The IrFe−N−C catalysts hold great potential for use in various electrochemical energy storage and conversion devices.
- Novel Quasi‐Liquid K‐Na Alloy as a Promising Dendrite‐Free Anode for Rechargeable Potassium Metal BatteriesPublication . Tai, Zhixin; Li, Yi; Liu, Yajie; Zhao, Lanling; Ding, Yu; Lu, Ziyu; Peng, Zhijian; Meng, Lijian; Yu, Guihua; Liu, LifengRechargeable potassium metal batteries are promising energy storage devices with potentially high energy density and markedly low cost. However, eliminating dendrite growth and achieving a stable electrode/electrolyte interface are the key challenges to tackle. Herein, a novel "quasi-liquid" potassium-sodium alloy (KNA) anode comprising only 3.5 wt% sodium (KNA-3.5) is reported, which exhibits outstanding electrochemical performance able to be reversibly cycled at 4 mA cm-2 for 2000 h. Moreover, it is demonstrated that adding a small amount of sodium hexafluorophosphate (NaPF6 ) into the potassium bis(fluorosulfonyl)imide electrolyte allows for the formation of the "quasi-liquid" KNA on electrode surface. Comprehensive experimental studies reveal the formation of an unusual metastable KNa2 phase during plating, which is believed to facilitate simultaneous nucleation and suppress the growth of dendrites, thereby improving the electrode's cycle lifetime. The "quasi-liquid" KNA-3.5 anode demonstrates markedly enhanced electrochemical performance in a full cell when pairing with Prussian blue analogs or sodium rhodizonate dibasic as the cathode material, compared to the pristine potassium anode. Importantly, unlike the liquid KNA reported before, the "quasi-liquid" KNA-3.5 exhibits good processability and can be readily shaped into sheet electrodes, showing substantial promise as a dendrite-free anode in rechargeable potassium metal batteries.
- Sulfur and phosphorus co-doped FeCoNiCrMn high-entropy alloys as efficient sulfion oxidation reaction catalysts enabling self-powered asymmetric seawater electrolysisPublication . Yu, Zhipeng; Boukhvalov, Danil W.; Tan, Hao; Xiong, Dehua; Feng, Chuangshi; Wang, Jingwei; Wang, Wei; Zhao, Yang; Xu, Kaiyang; Su, Weifeng; Xiang, Xinyi; Lin, Fei; Huang, Haoliang; Zhang, Fuxiang; Zhang, Lei; Meng, Lijian; Liu, LifengSeawater electrolysis (SWE) represents a promising approach to green hydrogen (H2) production but currently faces substantial challenges such as the interference of chlorine chemistry and high energy consumption. In this work, we demonstrate that by replacing the energy-demanding oxygen evolution reaction (OER) with the sulfion oxidation reaction (SOR) and by implementing the concept of bipolar membrane (BPM) electrolysis in an acid-base dual electrolyte system, not only can the notorious chlorine evolution reaction (CER) be completely circumvented, but the energy consumption of SWE be significantly reduced. To do so, we develop a sulfur and phosphorus co-doped FeCoNiCrMn high entropy alloy (HEA-SP) catalyst, which shows good electrocatalytic performance for the SOR in alkaline-saline water. This can be attributed to the abundant lattice defects and strains in HEA-SP, leading to a high density of active sites and an optimized electronic structure favorable for the SOR. Moreover, density functional theory calculations and in situ Raman spectroscopy characterization reveal the crucial role of imperfect sulfur coverage on the HEA in facilitating the formation of Sx clusters during the SOR. Using the HEA-SP as anode catalysts, the SOR-assisted SWE only needs electrical energy of 0.253 kWh to produce one cubic meter of H2 at 100 mA cm−2, in the presence of a BPM. Impressively, chlorine-free H2 production from seawater and upgrading of sulfions to valuable sulfur can occur simultaneously and spontaneously at 10 mA cm−2, highlighting the great potential of the HEA-SP catalysts and the asymmetric cell design to enable energy- and cost-effective seawater electrolysis.
- Efficient hydrogen production by saline water electrolysis at high current densities without the interfering chlorine evolutionPublication . Yu, Zhipeng; Xu, Junyuan; Meng, Lijian; Liu, LifengSeawater electrolysis powered by renewable energy sources has been proposed to be a potentially cost-effective approach to green hydrogen production. However, the long-standing issue regarding the chlorine evolution reaction (CER) that deteriorates the performance of electrocatalysts and other components of electrolyzers has been impeding the market adoption of direct seawater electrolyzers. Herein, we demonstrate that coupling the cathodic hydrogen evolution reaction (HER) with the hydrazine oxidation reaction (HzOR) taking place at the anode enables the alkaline–saline water electrolysis to occur at a high current density without the unfavorable, interfering CER. Using bifunctional carbon paper supported Co–Ni–P nanowires (Co–Ni–P/CP) as the cathode and anode, we have accomplished hydrogen production in the alkaline–saline–hydrazine electrolyte at 500 mA cm−2 with a small cell voltage of only 0.533 V and outstanding stability of 80 hours with minimal degradation.