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The conversion of CO2 into fuels or commodity chemicals by electrochemical or photochemical reduction is a promising strategy to relieve the ongoing energy crisis and increasing environmental pollution. Inspired by naturally occurring bimetalloenzymes, we have designed hetero–bimetallic CO2 reduction catalysts (FeM) that involve linking an iron tetraphenylporphyrin (FeP) with a tripyridylamine (TPA) moiety, which provides a distal chelating site for Cu2+ or Zn2+. We found that the introduction of Cu2+ or Zn2+ to FeP greatly enhances its efficiency as a catalyst for the electrochemical reduction of CO2. To gain insights into the observed synergistic effect, we performed mechanistic studies together with density functional theory (DFT) calculations. Our results show that Cu2+ or Zn2+ activates CO2 towards reduction due to its Lewis acidity; it also functions as an oxo acceptor from CO2. FeM also functions as an efficient catalyst for the visible‐light‐driven reduction of CO2 using either [Ru(bpy)3] Cl2 or fac‐Ir(ppy)3 (where bpy=2,2'‐bipyridine, ppy=2‐phenylpyridine) as photosensitizer and 1,3‐dimethyl‐2‐phenyl‐2,3‐dihydro‐1H‐benzo[d] imidazole (BIH) as sacrificial reductant. Again, the catalytic efficiency is enhanced by the presence of Cu2+ or Zn2+. Our results provide a general strategy for the design of a series of hetero‐bimetallic catalysts for the reduction of CO2. [ABSTRACT FROM AUTHOR]

Although hard carbon (HC) demonstrates superior initial Coulombic efficiency, cycling durability, and rate capability in ether‐based electrolytes compared to ester‐based electrolytes for sodium‐ion batteries (SIBs), the underlying mechanisms responsible for these disparities remain largely unexplored. Herein, ex situ electron paramagnetic resonance (EPR) spectra and in situ Raman spectroscopy are combined to investigate the Na storage mechanism of HC under different electrolytes. Through deconvolving the EPR signals of Na in HC, quasi‐metallic‐Na is successfully differentiated from adsorbed‐Na. By monitoring the evolution of different Na species during the charging/discharging process, it is found that the initial adsorbed‐Na in HC with ether‐based electrolytes can be effectively transformed into intercalated‐Na in the plateau region. However, this transformation is obstructed in ester‐based electrolytes, leading to the predominant storage of Na in HC as adsorbed‐Na and pore‐filled‐Na. Furthermore, the intercalated‐Na in HC within the ether‐based electrolytes contributes to the formation of a uniform, dense, and stable solid–electrolyte interphase (SEI) film and eventually enhances the electrochemical performance of HC. This work successfully deciphers the electrolyte‐dominated Na+ storage mechanisms in HC and provides fundamental insights into the industrialization of HC in SIBs. [ABSTRACT FROM AUTHOR]

It is highly desirable to raise the charge cutoff voltage to realize the potential of LiCoO2 (LCO) with its ultra‐high theoretical capacity of 275 mAh g‐1. However, rapid fading due to structure collapse caused by the formation of the H1‐3 metastable phase and the release of surface lattice oxygen has largely hindered the operation of LCO under voltages of higher than 4.55 V. Here, stable cycling of LCO at 4.6 V through hierarchical doping engineering with inert P‐outside and active Ni‐inside dual doping is achieved. This ingenious outside‐in structure design enables Ni2+ occupation in the Li layer in the bulk layered phase and P gradient doping at the superficial lattice. Compared with the conventional inert element substitution strategy, the doped active Ni2+ can not only serve as a "pillar" to restrain the formation of the metastable H1‐3 phase, but also regulate the electronic structure of LCO and trigger the superexchange interaction of Ni2+‐O‐Co4+, together with strong P–O coordination to substantially suppress the lattice oxygen escape from the surface. Therefore, it considerably reduces the risk of layer structure collapse and consequently achieves stable and high‐capacity operation over 4.6 V. This hierarchical outside‐in doping strategy may serve as inspiration for stabilizing high energy electrode materials working under high voltages. [ABSTRACT FROM AUTHOR]

Fabrication of a highly porous sulfur host and using excess electrolyte is a common strategy to enhance sulfur utilization. However, flooded electrolyte limits the practical energy density of Li–S pouch cells. In this study, a novel Fe0.34Co0.33Ni0.33S2 (FCN) is proposed as host for sulfur to realize Ah‐level Li–S full cells demonstrating excellent electrochemical performances under 2 µL mg−1 lean electrolyte conditions. Moreover, Kelvin probe force microscopy shows that the FCN surface contains positive charge with a potential of ≈70 mV, improving the binding of polysulfides through Lewis acid base interaction. In particular, the FCN@S possesses inherent electrochemical activity of simultaneous anionic and cationic redox for lithium storage in the voltage window of 1.8–2.1 V, which additionally contributes to the specific capacity. Due to the low carbon content (≈10 wt%), the sulfur loading is as high as ≈6 mg cm−2, approaching an outstanding energy density of 394.9 and 267.2 Wh kg−1 at the current density of 1.5 and 4 mA cm−2, respectively. Moreover, after 60 cycles at 1.5 mA cm−2, the pouch cell still retains an energy of 300.2 Wh kg−1. This study represents a milestone in the practical applications of high‐energy Li–S batteries. [ABSTRACT FROM AUTHOR]

Aero-engine is an essential component of the aircraft. Due to the high cost of raw materials and precise structure, the maintenance cost of aero-engine is great. By repairing worn blades rather than replacing them with new ones, the aero-engine maintenance cost can be reduced effectively. For repairing worn blades, existing methods mainly generate tool path based on the reconstructed surface with the aid of CAM software. In this paper, an effective tool path generation method for repairing blades after additive manufacturing process is presented, which overcomes the low efficiency and complicated process weakness of existing methods. The tool path is generated directly with point clouds without surface fitting. By splitting point cloud and analyzing geometric parameters of points, machining areas could be recognized from the entire blade model. The cutter location point is generated by extending on the normal vector direction of the corresponding point. The five-axis tool path could be obtained by connecting cutter location points in turns. Tool path optimization is further studied after the generation process. These algorithms eliminate the time consumption caused by surface fitting operations, and could generate five-axis tool paths for repairing aero-engine blades efficiently. [ABSTRACT FROM AUTHOR]