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Lead-free double perovskite nanocrystals (NCs) have garnered significant attention due to their non-toxicity and excellent stability, offering vast potential applications in the field of optoelectronics. They are considered promising substitutes for lead-based perovskite NCs. Herein, we successfully synthesized monodisperse, uniformly sized, cubic-shaped Cs 2 AgIn 1-x Bi x Cl 6 (0 ≤ x ≤ 1) NCs via a simple hot injection approach. The Cs 2 AgInCl 6 NCs exhibit a lower photoluminescence quantum yield (PLQY) of 3.9 % due to the presence of parity-forbidden transitions. However, with the introduction of Bi3+ alloying, the parity-forbidden transitions are broken, transforming into direct transitions allowed by parity. This transformation leads to efficient bright yellow emission, with the highest PLQY reaching up to 31.6 % (Cs 2 AgIn 0.90 Bi 0.10 Cl 6 NCs). Adjusting the Bi3+ alloying concentration allows tuning the NCs band gap from 3.62 eV to 2.88 eV, and the exciton lifetime can be extended from 5.99 ns to 24.88 ns. Temperature-dependent photoluminescence spectra and density functional theory calculations indicate that Bi3+ alloying increases the exciton binding energy, weakens the electron-phonon coupling, and breaks parity-forbidden transitions. Moreover, Cs 2 AgIn 0.90 Bi 0.10 Cl 6 NCs display outstanding stability under ambient conditions, laying a solid foundation for their applications in optoelectronics. The results of this study open a new pathway to enhance the optical performance of lead-free double perovskite nanomaterials. • Monodisperse Bi3+ alloyed Cs 2 AgInCl 6 nanocrystals were prepared. • Bi3+ alloyed Cs 2 AgInCl 6 nanocrystals show a improved PLQY of 31.6 %. • Bi3+ alloyed Cs 2 AgInCl 6 nanocrystals demonstrate a remarkable stability. [ABSTRACT FROM AUTHOR]

Perovskite oxides with tailored elements and structures endow promising electrocatalytic properties for hydrogen evolution reaction (HER) due to considerable activity and satisfactory long‐term operating stability. However, the synthesis of 1D perovskite nanostructures with anion dopants remains a challenge, as well as insights into the performance origin from experimental and theoretical views. Herein, combined with electrospinning and phosphatizing strategies, P‐doped Pr0.5La0.5BaCo2O5+δ perovskite nanofibers (P‐PLBC‐F) are reported for highly active HER catalysts. The P‐PLBC‐F catalyst outperforms the classic perovskites and can be comparable to the commercial Pt/C (wtPt= 20%) benchmark, exhibiting a Tafel slope of −32.9 mV dec−1 and overpotential of −307 mV at 500 mA cm−2disk in alkaline media. The highly catalytic activity benefits from the desired 1D nanostructure, steered electronic structures (charge transfer energy ΔCo‐P= 0.79 eV) and Gibbs free energy for the H* desorption (1.02 eV) induced by the P3− doping, as supported by density functional theory calculations. The findings described here unveil the phosphatizing mechanism of the perovskites for catalyzing the hydrogen production, and broaden horizons in terms of rational designs of novel perovskite‐based catalysts for sustainable energy. [ABSTRACT FROM AUTHOR]

The Li2MoO3 (LMO) material is one promising cathode material for lithium-ion batteries due to its high specific capacity and absence of oxygen release. However, its surface instability in air and poor conductivity have limited its application. To solve these problems, the Ru element has been successfully introduced into the LMO lattice with the aid of the molten salt method. XRD and TEM characterization showed that the introduction of Ru does not change the crystal structure but expands the crystal plane spacing of the {001} facets, which is further evidenced by density functional theory (DFT) calculations. XPS and EDS tests indicated that the introduction of Ru inhibits the oxidation of Mo species and leads to a more uniform distribution of the material. In addition, DFT calculations revealed that covalent interactions are formed between Mo4d/Ru4d and O2p orbitals, leading to a significant reduction of the band gap. Therefore, Ru-doped samples exhibit good electrochemical performances. The initial discharge capacity of an LMRO-2 sample reaches 299.1 mA h g−1 at a 1C rate, and the capacity remains at 125.2 mA h g−1 after 100 cycles. In comparison, the initial discharge capacity of pure phase sample LMO is only 250.5 mA h g−1 under the same conditions, and the capacity remains only at 76.5 mA h g−1 after 100 cycles. The present results confirmed that Ru doping is an effective strategy to improve the performance of the LMO cathode material. [ABSTRACT FROM AUTHOR]

• The 2D porous Ni/NiMoN heterojunction nanobelts catalysts with tunable components were designed and synthesized. • The 2D porous Ni/NiMoN heterojunction have good ability for mass/charge transfer and optimized electronic structure for H* adsorption. • The Ni/NiMoN catalyst exhibits excellent HER activity and durability with low overpotential of 48 mV at 10 mA cm−2. • The electrolyzer composed of 2D Ni/NiMoN catalyst and matched OER catalyst only requires a low cell voltage of 1.47 V to attain 10 mA cm−2 with excellent durability for 96 h. • The origin of superior performance of the heterostructures is elucidated by combining density functional theory calculations and work function test etc. The design of the electrocatalysts with the plentiful heterojuctional interface and large-accessible surface is desired to boost the HER performance, but it remains a challenge. Herein, we showed the design of 2D Ni/Ni 0.2 Mo 0.8 N porous heterojunction nanobelts as effective catalyst for the HER. The intimate combination of Ni and Ni 0.2 Mo 0.8 N can make the formation of the heterojuctional interface with plentiful active sites. The 2D porous structure can provide large accessible surface with less resistance for the transmission of the electrolytes, thus promoting the mass/charge transfer. The ratio of Ni and Ni 0.2 Mo 0.8 N can be easily tuned by regulating the precursor composition, which is important to give catalysts with optimized interface and suitable pores. Density functional theory calculations reveal that the interaction between Ni and Ni 0.2 Mo 0.8 N at the heterointerface can largely improve the intermediate H* adsorption kinetics (ΔG H* = -0.07 eV). Due to the above advantages, the optimized catalysts exhibited excellent HER activity with a low overpotential of 48 mV in 1 M KOH at 10 mA cm−2 (without iR correction), which is superior to the most reported non-noble metal-based catalysts, and the long-term durability with no obvious degradation after continual operation of 48 h Notably, an electrolyzer assembled by the optimized Ni/Ni 0.2 Mo 0.8 N cathode with NiFe-LDH anode only requires a low operating voltage of 1.47 V to deliver 10 mA cm−2 in 1 M KOH, surpassing the corresponding Pt/NF||RuO 2 /NF electrolyzer (1.61 V) and most of reported electrolyzers. The 2D porous Ni/NiMoN heterojunction nanobelts were successfully obtained as highly effective hydrogen evolution electrocatalysts. Benefiting from the redistribution of electrons at the interface and the porous structure, the catalyst exhibits excellent HER activity and durability, affording low overpotential of only 48 mV at 10 mA cm−2. The Ni/NiMoN heterojunction catalyst can match well with an appropriate OER catalyst to realize overall water splitting, only requiring a cell voltage of 1.47 V to achieve 10 mA cm−2 with excellent durability for 96 h, surpassing the corresponding Pt/C/NF||RuO 2 /NF electrolyzer (1.61 V) and most of recently reported Ni/Mo-based compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

Designing efficient, stable, and inexpensive catalysts for water splitting was critical for efficient, sustainable energy conversion. Here, a one-pot hot-colloidal route was adopted to synthesize the mono-dispersed NiCoP catalyst with a particle size of∼5.0 nm. To further improve the structural stability and electronic conductivity of the catalysts, carbon nanotubes (CNTs) were introduced. The theoretical calculations suggested that a synergistic effect between Ni and Co in the NiCoP catalyst not only leads to an obvious charge redistribution but also facilitates the electron transfer from the surface to the reactant intermediates, being responsible for the optimal ΔG H* of the catalyst. As a result, NiCoP/CNTs exhibited good HER performance both in acidic and alkaline electrolytes. The overpotentials under alkaline and acidic electrolytes were 110 mV and114 mV at a current density of 10 mA cm−2, respectively. In comparison with pristine Ni 2 P(Co 2 P), the overpotential of NiCoP/CNTs in acidic and alkaline electrolytes was reduced by 50(24) and 62(30) mV at the current density of 10 mA cm−2. Even at the current densities of 50 and 200 mA cm−2, NiCoP/CNTs still retains a much lower overpotential than other samples. Our results revealed the important roles of the synergistic effect between the transition metals and the interaction between CNTs and the phosphides, which provides some useful information for the design and optimization of relevant HER catalysts. • Synergistic interaction between Ni and Co in NiCoP/CNTs leads to charge redistribution favoring electron transfer. • CNTs can improve the conductivity of the material, reduce the interfacial impedance and increase specific surface area. • CNTs facilitate anchoring and uniform distribution of catalyst particles. [ABSTRACT FROM AUTHOR]

Ni/ZnIn 2 S 4 nanosheet assembly with sulfur vacancy and Schottky junction (Ni/DZIS) is fabricated and shows much better the photocatalytic hydrogen evolution rate without any noble metal cocatalysts. The improved photocatalytic performance is mainly attributed to the synergism of sulfur vacancy and Schottky junction accelerating the photogenerated charge transfer and thus inhibiting the charge recombination. [Display omitted] • Fabrication of Ni/ZnIn 2 S 4 nanosheet assembly with sulfur vacancy and Schottky junction (Ni/DZIS) through facile ethanediol-assisted solvothermal method. • The location of Ni at the hollow site of three S atoms next to sulfur vacancy on the ZnIn 2 S 4 (0 0 6) face. • The photocatalytic hydrogen evolution rate of Ni/DZIS up to 703 μmol g−1h−1 without any noble metal cocatalysts. Surface and interface engineering play vital roles on improving the photocatalytic hydrogen evolution. Herein, Ni/ZnIn 2 S 4 nanosheet assembly with sulfur vacancy and Schottky junction (Ni/DZIS) is fabricated through facile ethanediol-assisted solvothermal method. Density functional theory (DFT) calculation reveals that the Ni is absorbed at the hollow site of three S atoms next to sulfur vacancy on the ZnIn 2 S 4 (0 0 6) face due to the formation of sulfur vacancy. The resultant Ni/DZIS Schottky junction exhibits high photocatalytic H 2 evolution rate of 703 μmol g−1h−1 without any noble metal cocatalysts, which is 2.6 times higher than that of pristine ZnIn 2 S 4 nanosheets. The improved photocatalytic performance is mainly attributed to the synergism of sulfur vacancy and Schottky junction accelerating the photogenerated charge transfer and thus inhibiting the charge recombination. Moreover, the photocatalytic performance of Ni/DZIS nearly keeps constant even after six recycles, indicating the high stability and potential applications in field of energy. This work provides a convenient strategy for constructing efficient defective heterojunction assembly photocatalysts via surface and interface engineering. [ABSTRACT FROM AUTHOR]

The controllable construction of Fe,N co-doped carbon (Fe-N-C) nanocomposite has highly potential in replacing the noble metal catalysts. Herein, the Fe/N/P-tridoped expanded carbon nanotubes (P-Fe-N-CNTs) are prepared according to a simple one-step pyrolysis procedure. The unexpanded Fe-N-C carbon nanotubes (Fe u -N-CNTs) are also fabricated for comparision. The expanded P-Fe-N-CNTs yields a high half-wave potential (E 1/2) of 0.8843 V compared with unexpanded Fe u -N-CNT and commercial Pt/C. Furthermore, the expanded P-Fe-N-CNT as catalyst of Zn-air battery achieves high electrocatalytic performance, which is better than commercial Pt/C material. The unique architecture of expanded P-Fe-N-CNTs can improve the specific surface area and promote the formation the abundant active site, thus promoting the ORR kinetic process. Density functional theory (DFT) calculations futher confirm that suitable P doping can regulate the electronic structures of the active catalytic sites. The work provides a controllable way to prepare rational expanded P-Fe-N-CNTs for different applications, especially in Zn-air battery. [Display omitted] • The morphology of Fe/N/P-tridoped expanded carbon nanotubes are firstly regulated. • The suitable P dopant can optimize the electronic structures of active sites. • The expanded P-Fe-N-CNTs promotes the formation of abundant active site. • The P-Fe-N-CNTs catalyst shows high ORR performance. • The rational expanded P-Fe-N-CNTs exhibits a potential application prospect. [ABSTRACT FROM AUTHOR]

[Display omitted] • The intercalation of NH 4 + into Fe 4 [Fe(CN) 6 ] 3 is systematically analyzed. • Fe 4 [Fe(CN) 6 ] 3 shows superior cycling stability as NH 4 + storage host. • Hydrogen bond between NH 4 + and N species of Fe 4 [Fe(CN) 6 ] 3 is initiatively proposed. • A low-cost aqueous NH 4 + full cell is assembled with durable cycling stability. Low-cost and high-safety aqueous batteries can provide high-value opportunities for grid-scale energy storage. In this article, the electrochemical intercalation of non-metallic charge carrier (NH 4 +) into iron hexacyanoferrate (Fe 4 [Fe(CN) 6 ] 3) has been systematically analyzed in aqueous NH 4 + batteries. Comprehensive discussions are made based on the experimental and calculation results. Multiple testing methods are applied to illustrate the intercalation mechanism, and novel hydrogen bonds formed between NH 4 + and N species of Fe 4 [Fe(CN) 6 ] 3 is initiatively proposed for the stabilization of the system, based on the density functional theory (DFT) calculations. Meanwhile, the density of states (DOSs) data of Fe 4 [Fe(CN) 6 ] 3 with and without HN 4 + intercalation further indicates the formation of the strong covalent bonds, which is responsible for the good structural stability of the compound. Additionally, a low-cost rocking-chair aqueous NH 4 + full cell is assembled based on NH 4 ·Fe 4 [Fe(CN) 6 ] 3 cathode and 3,4,9,10-Perylene-bis(dicarboximide) (PTCDI) anode, which exhibits durable cycling stability (capacity retention of nearly 90% over 300 cycles) as expected for great potential applications in the sustainable batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • The intercalation of NH 4 + into Fe 4 [Fe(CN) 6 ] 3 is systematically analyzed. • Fe 4 [Fe(CN) 6 ] 3 shows superior cycling stability as NH 4 + storage host. • Hydrogen bond between NH 4 + and N species of Fe 4 [Fe(CN) 6 ] 3 is initiatively proposed. • A low-cost aqueous NH 4 + full cell is assembled with durable cycling stability. Low-cost and high-safety aqueous batteries can provide high-value opportunities for grid-scale energy storage. In this article, the electrochemical intercalation of non-metallic charge carrier (NH 4 +) into iron hexacyanoferrate (Fe 4 [Fe(CN) 6 ] 3) has been systematically analyzed in aqueous NH 4 + batteries. Comprehensive discussions are made based on the experimental and calculation results. Multiple testing methods are applied to illustrate the intercalation mechanism, and novel hydrogen bonds formed between NH 4 + and N species of Fe 4 [Fe(CN) 6 ] 3 is initiatively proposed for the stabilization of the system, based on the density functional theory (DFT) calculations. Meanwhile, the density of states (DOSs) data of Fe 4 [Fe(CN) 6 ] 3 with and without HN 4 + intercalation further indicates the formation of the strong covalent bonds, which is responsible for the good structural stability of the compound. Additionally, a low-cost rocking-chair aqueous NH 4 + full cell is assembled based on NH 4 ·Fe 4 [Fe(CN) 6 ] 3 cathode and 3,4,9,10-Perylene-bis(dicarboximide) (PTCDI) anode, which exhibits durable cycling stability (capacity retention of nearly 90% over 300 cycles) as expected for great potential applications in the sustainable batteries. [ABSTRACT FROM AUTHOR]