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Interfacial interactions and electronic properties of graphene/CH 3 NH 3 PbI 3 heterojunctions were investigated by first-principles calculations incorporating semiempirical dispersion-correction scheme to describe van der Waals interactions. Two lattice match configurations between graphene and CH 3 NH 3 PbI 3 (0 0 1) slab were constructed in parallel contact and both of them were verified to form remarkable van der Waals heterojunctions with similar work functions. Our calculated energy band structures show that the Dirac-cone of graphene and the direct band gap of CH 3 NH 3 PbI 3 are still preserved in the heterojunctions, thus graphene can be a promising candidate either as a capping or supporting layer for encapsulating CH 3 NH 3 PbI 3 layer. It is identified that the Schottky barrier of graphene/CH 3 NH 3 PbI 3 heterojunctions can be controlled by the interlayer distance and affected by the stacking pattern of graphene and CH 3 NH 3 PbI 3 . The 3D charge density differences present the build-in internal electric field from graphene to CH 3 NH 3 PbI 3 after interface equilibrium and thus, a low n -type Schottky barrier is needed for high efficient charge transferring in the interface. The possible mechanism of the band edge modulations in the heterojunctions and corresponding photoinduced charge transfer processes are also described. [ABSTRACT FROM AUTHOR]

Aqueous rechargeable zinc-ion batteries (AZIBs) are in a period of vigorous development due to their unparalleled advantages, including low cost, high safety and environmentally friendly etc. However, the structural damage, dissolution, low conductivity of electrode materials and slow diffusion kinetics of Zn2+ ions carriers significantly limit the development of AZIBs. Herein, for the first time, we propose a general strategy for constructing multifunctional intramolecular hydrogen bond network through N-H∙∙∙O (NH 4 +) and O-H∙∙∙O (H 2 O) bonds while suppressing material dissolution (V, Mn species), enhancing the stability of layered structures, and accelerating the rapid diffusion of protons. To better reveal the hydrogen bond and enhanced proton transport, a range of in/ex-situ characterization techniques in conjunction with DFT calculations have been implemented. As a proof of concept, this strategy has proven to be universally applicable, with both vanadium oxide (400.6 Wh kg−1/6489.3 W kg−1, 85% over 4000 cycles) and manganese oxide (433.6 Wh kg−1/2972.8 W kg−1, 100% after 500 cycles) achieving significant electrochemical performance improvements, particularly in terms of rate performance and cycle performance, which are better than most comparable materials. The insights obtained in this study have deepened the understanding based on the hydrogen bond in AZIBs and also brought new opportunities for improving the energy density of other types of aqueous batteries in the future. [Display omitted] • A universal strategy to achieve the construction of stable hydrogen bond network. • The multifunctional effect of hydrogen bond network were verified for the first time. • The significant electrochemical properties improvements were realized by hydrogen bond network design. • The hydrogen bond strategy has great potential and reference significance in other layered materials or other types of energy storage systems. [ABSTRACT FROM AUTHOR]

A special Z-scheme hybrid structure with 2D configuration comprising of g-C 3 N 4 , reduced graphene oxide (RGO), and BiOI (g-C 3 N 4 /BiOI/RGO) was rationally constructed and immobilized on Ni foam with RGO functioned as electron transfer mediator and binder. • Ternary 2D g-C 3 N 4 /BiOI/RGO hybrid immobilized on Ni foam was successfully built. • RGO functioned as electron transfer mediator and binder. • Hybrid immobilized on Ni foam displayed an excellent photocatalytic performance. • Electron transfer route of hybrid conformed to the Z-scheme mechanism. In this work, a special hybrid structure with 2D configuration comprising of g-C 3 N 4 , reduced graphene oxide (RGO), and BiOI (g-C 3 N 4 /BiOI/RGO) was rationally constructed and immobilized on Ni foam with RGO functioned as electron transfer mediator and binder. The immobilized 2D g-C 3 N 4 /BiOI/RGO hybrid structure exhibited the enhanced photocatalytic CO 2 reduction to CO and the methyl orange (MO) degradation efficiency under visible light irradiation. Particularly, the hybrid heterojunction with a mass ratio 6% of BiOI to g-C 3 N 4 displayed the highest CO yield and degradation rate constant for MO, which was 1.6 times and 3 times of g-C 3 N 4 /RGO binary heterojunction immobilized on Ni foam. The enhanced photocatalytic activity was ascribed to the rapid charge separation. More importantly, combined with the theoretical calculations on the work functions of g-C 3 N 4 , rGO and BiOI, the experimental results clarified the charges transfer route of g-C 3 N 4 /BiOI/RGO heterojunction conforming to the Z-scheme mechanism. [ABSTRACT FROM AUTHOR]

• Charge redistribution on the interface formed an interfacial internal electric field. • SnO x decreased work function of Sn-BiOCl and improved its photocatalytic reducibility. • Oxygen vacancies and internal electric field synergistically improved light absorption and charge separation. • Photodegradation activity of Sn-BiOCl increased 14 times higher than that of BiOCl. Solar-to-chemical energy conversion is valuable and sustainable strategy for energy and environmental crisis through photocatalysis. The amorphous SnO x modified BiOCl (Sn-BiOCl) full-spectrum-responsive catalysts were designed and synthesized through solvothermal method. The introduced Sn regulates the growth of BiOCl to form ultrathin nanosheets with surface oxygen vacancies. And the surface modification of SnO x induces interfacial internal electric field via charge redistribution on the interface of BiOCl and SnO x to accelerate the photogenerated charge separation. The modification of SnO x decreased work function of Sn-BiOCl and thus elevated its conduction band and valence band simultaneously, leading enhanced photocatalytic reducibility with the improved generation rate of ·O 2 −. The surface SnO x and oxygen vacancies of Sn-BiOCl broadened light absorption range and enhanced photocatalytic performance synergistically, resulting in 14-fold increased photodegradation rate of phenol compared with pure BiOCl under full spectrum. This method is also able to expand to other metal ions (such as Fe3+, In3+ and Sb3+). This work provides a valuable concept in structure regulating for enhanced photocatalytic performance in the removal of organic pollutants by interfacial internal electric field and surface oxygen vacancies. [ABSTRACT FROM AUTHOR]

In this work, the corrosion behavior of Mg-SiO 2 nanocomposites, fabricated by powder metallurgy coupled with hybrid microwave sintering and subsequent hot extrusion, was investigated using electrochemical, hydrogen evolution and weight loss measurements. Localized intergranular corrosion behavior was analyzed based on microstructural characteristics, which were characterized by scanning electron microscopy, energy-dispersive x-ray spectroscopy, and high-resolution transmission electron microscopy (HRTEM). In particular, copious numbers of Mg/MgO misfit dislocations were identified at the interface between the matrix Mg and SiO 2 nanoparticles; indeed, first principles calculations revealed that the MgO/Mg interfaces were relatively weakly bonded as compared to the close-packed interfacial Mg(0001)//MgO(111) structure. Using geometrical phase analysis of the HRTEM images to determine the lattice strains in the Mg/MgO interfacial area, we conclude that the highly strained and weakly bonded Mg/MgO interfaces act to promote significant localized dissolution and thus play a dominant role in intensifying intergranular corrosion in these nanocomposites. Graphical Abstract [Display omitted]. [ABSTRACT FROM AUTHOR]