Defects have been found to enhance the electrocatalytic performance of NiFe-LDH for oxygen evolution reaction (OER). Nevertheless,their specific configuration and the role played in regulating the surface reconstruction of electrocatalysts remain ambiguous.H erein, cationic vacancy defects are generated via aprotic-solvent-solvation-induced leaking of metal cations from NiFe-LDH nanosheets.D FT calculation and in situ Raman spectroscopic observation both reveal that the as-generated cationic vacancy defects tend to exist as V M (M = Ni/Fe);under increasing applied voltage,they tend to assume the configuration V MOH ,a nd eventually transform into V MOH-H whichisthe most active yet most difficult to form thermodynamically.M eanwhile,w ith increasing voltage the surface crystalline Ni(OH) x in the NiFe-LDH is gradually converted into disordered status;u nder sufficiently high voltage when oxygen bubbles start to evolve,l ocal NiOOH species become appearing,w hich is the residual product from the formation of vacancy V MOH-H .T hus,w ed emonstrate that the cationic defects evolve along with increasing applied voltage (V M ! V MOH ! V MOH-H ), and reveal the essential motif for the surface restructuration process of NiFe-LDH (crystalline Ni(OH) x ! disordered Ni(OH) x ! NiOOH). Our work provides insight into defect-induced surface restructuration behaviors of NiFe-LDH as at ypical precatalyst for efficient OER electrocatalysis.

Here, a new class of quantum dots, that is, sulphur quantum dots (SQDs), which are synthesized by the phase interfacial reaction, is reported. The prepared SQDs are monodisperse with a narrow size distribution (average 1.6 nm in size), excellent aqueous dispersibility, ultrahigh photostability, and lowly toxicity. Because of abundant oxidized sulphur species on the surface of SQDs, the incorporation of TiO2 with SQDs results in a synergistic effect for the TiO2‐based photocatalysts offering more effective environmental applications. It is demonstrated that SQDs‐TiO2 nanocomposite can enhance the photocatalytic activity of producing hydrogen (enhancement factor for 191) in methanol‐water system. The SQDs also can used as fluorescent probe for highly selective quantitative detection Fe3+ in an aqueous solution contained various metal ions.

Li2CO3 is the cathodic discharge product of a Li-CO2/O2 battery and is difficult to electrochemically decompose. The accumulation of Li2CO3 leads to battery degradation and results in a short lifespan. Herein, a carbon nanotube supported Ru/NiO@Ni catalyst (Ru/NiO@Ni/CNT) is synthesized with Ru nanoparticles (∼2.5 nm) anchored on the surface of core–shell structure NiO@Ni nanoparticles (∼17 nm). We found strong interfacial interactions between Ru nanoparticles and NiO. XRD and XPS analysis revealed that the presence of Ru could protect the Ni species from being deeply oxidized while the NiO species could modify the local electronic structure of Ru, inducing a higher oxidation state. When such a Ru/NiO@Ni/CNT catalyst is used as a cathode in Li-CO2/O2 (v:v = 4:1) batteries, a long cycling life of 105 cycles at a cutoff capacity of 1000 mAh g–1 with an overpotential as low as 1.01 V was achieved, which is significantly better than 75 and 44 cycles with Ru/CNT and NiO@Ni/CNT catalysts, respectively, and confirms the strong synergetic effect between the Ru and NiO species in the electrocatalytic decomposition of Li2CO3. Density functional theory (DFT) calculations of the electrochemical decomposition of Li2CO3 with the assistance of RuO2 indicates that the formation of O2 is the rate-determining step. In addition, the formation and decomposition process of Li2CO3 was illuminated at a molecular level by in situ FTIR spectroscopy with Ru/NiO@Ni/CNT catalysts.

A novel MPL bifunctional material fabricated by an easy and green approach was applied for the simultaneous removal of potentially toxic metals and anionic dyes.

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