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An interfacial C-S bond bridged ZnS/C 3 N 5 S-scheme heterojunction was constructed for photocatalytic H 2 evolution. Benefiting from the interfacial covalent bond, enhanced internal-electric-field strength, and accelerated surface photocatalytic reaction, the photocatalytic H 2 production of ZnS/C 3 N 5 was 3.2 and 2.5 times higher than those of ZnS/C 3 N 4 and ZnS/C 3 N 5 -300 without C-S bond. [Display omitted] • C-S bond is susceptive to preparation temperatures, and it is broken above 300 °C. • C-S bond promotes e − separation and improves H 2 O adsorption and activation behaviors. • IEF strength of ZnS/C 3 N 5 with opposite direction is 2.6 times than that of ZnS/C 3 N 4. • e − transfer respectively follow S-scheme and type-II pathway in ZnS/C 3 N 5 and ZnS/C 3 N 4. • H 2 yield of ZnS/C 3 N 5 is 3.2 and 2.5 times than ZnS/C 3 N 4 and ZnS/C 3 N 5 -300 without C-S. An interfacial C-S bond bridged ZnS/C 3 N 5 heterojunction was constructed for photocatalytic H 2 evolution. Different from traditional type-II ZnS/C 3 N 4 heterojunction, the electron transfer followed S-scheme pathway, due to opposite internal-electric-field (IEF) directions in these two heterojunctions. The C-S bond formation was carefully investigated, and they were susceptive to the preparation temperatures. In photocatalytic reaction, C-S bond was functioned as the "high-speed channel" for electron separation and transfer, and the IEF strength in ZnS/C 3 N 5 was 1.86 × 108 V/m, 2.6 times higher than that in ZnS/C 3 N 4. Moreover, the C-S bond also altered the surface molecular structure of ZnS/C 3 N 5 , and hence the surface reaction was accelerated via improving H 2 O adsorption and activation behaviors. Benefiting from the S-scheme pathway, enhanced IEF strength, and accelerated surface reaction, the photocatalytic H 2 production over ZnS/C 3 N 5 reached up to 20.18 mmol/g/h, 3.2 and 2.5 times higher than those of ZnS/C 3 N 4 and ZnS/C 3 N 5 -300 without C-S bond. [ABSTRACT FROM AUTHOR]

[Display omitted] • NH 4 BS can dissolve in basic electrolyte without cosolvent. • NH 4 BS can alleviate the passivation of electrode surfaces by dissolving Li 2. • NH 4 BS can increase the dissociation degree of long-chain polysulfides.NH4BS can increase the dissociation degree of long-chain polysulfides. Based on the dissolution and conversion mechanism of lithium-sulfur (Li-S) batteries, insulating solid short-chain polysulfides (Li 2 S 2 /Li 2 S) will continuously passivate and corrode the active interface of cathode and anode, which seriously affects its performance. Herein, ammonium benzenesulfonate (NH 4 BS) is proposed as a soluble ammonium salt to dissolve Li 2 S in the ether electrolyte, according to the inductive effect of NH 4 + cation and O atom on Li-S bond. This is beneficial to alleviate the interface problem of electrodes and irreversible loss of active materials. Noticeably, soluble Li 2 S regulates its deposition behavior from 2D to 3D, which is conducive to the more effective use of conductive surface. Moreover, the addition of NH 4 BS can increase the dissociation degree of long-chain polysulfides, so that the diffusion rate and reaction kinetics of active substances are improved. Profiting from these functions, the Li-S cells with NH 4 BS act out excellent cyclic stability in the long cycle of 0.5 C and 2 C. Under the extreme conditions of high sulfur loading and low electrolyte-sulfur ratio, the cells with NH 4 BS can cycle stably for 196 cycles, which significantly prolongs the battery life. The proposal of NH 4 BS broadens a new idea to solve the interface problem of Li-S cells and stimulate the research enthusiasm of developing soluble ammonium salt. [ABSTRACT FROM AUTHOR]

A hybrid material of N -doped graphitic carbon shell-encapsulated FeCo alloy derived from metal–polyphenol network and melamine sponge is an effective electrocatalyst for ORR, OER, and HER. Exploiting low cost and durable electrocatalysts with high efficiency for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) is of great significance for energy conversion and storage applications. Herein, a hybrid electrocatalyst of FeCo alloy nanoparticles embedded in a porous N -doped carbon was prepared via a pyrolysis process of low-cost melamine sponge and mass-produced metal–polyphenol network. Benefting from the metal coordination of metal–polyphenol network and abundant N source of melamine sponge, the metal–N moiety and FeCo alloy nanoparticles (wtih a diameter around 50 nm) encapsulated in a N -doped graphene-like carbon layer were formed in-situ. Such intimate integration of graphene-like carbon-encapsulated FeCo alloys, metal–N active species, and porous structure is conducive to improve the catalytic activity and increase the catalytic durability in alkaline media. As a consequence, the as-prepared electrocatalyst exhibits the pronounced activity toward ORR, OER, and HER simultaneously under alkaline condition, particularly on the performances of potential, stability, and methanol tolerance. [ABSTRACT FROM AUTHOR]

Graphene quantum dots (GQDs) have been synthesized reproducibly by chemical oxidation (CO) of carbon nano-onions (nCNOs) and a one-step pulsed laser ablation (LA) of nCNOs in deionized water. The photoluminescence (PL) spectra show that the LA-GQDs have blue shifted emission relative to the CO-GQDs which is attributed to the effects of both particle sizes and surface functional groups. The CO-GQDs have an average diameter of 4.1(8) nm and a thickness corresponding to two or three graphene layers, while the LA-GQDs have an average diameter of 1.8(6) nm and a thickness comparable to a single layer of graphene. The CO-GQDs favor the presence of carboxylic groups and have a higher fraction of sp 2 carbons, while the LA-GQDs prefer the presence of hydroxyl groups and have a higher fraction of sp 3 carbons. PL lifetime data suggests that surface functional groups are the main source of radiative deactivation and the sp 2 carbon domains are mainly responsible for non-radiative decay. PL lifetimes are measured to be 7.9(6) ns for the emission from the carboxylic groups and 3.18(10) ns from the hydroxyl groups. Compared to CO, liquid-phase LA is a faster and cleaner one-step method for producing GQDs with fewer starting chemicals and byproducts. [ABSTRACT FROM AUTHOR]

[Display omitted] The development and exploration of high-entropy materials with tunable chemical compositions and unique structural characteristics, although challenging, have attracted increasingly greater attention over the past few years. Here, we report a universal and green method to prepare high-entropy layered (oxy)hydroxide (HE-LH) nanosheets under ambient conditions. This method is based on a self-reliant electrochemical process, utilizing only low-cost metal foils and electrolytes as reactant, with no need of involving extra alkali salts and/or organic reagents. Importantly, the composition of HE-LH nanosheets is widely tunable by simply adjusting the combination of metal foils. As a representative example, quinary layered (oxy)hydroxide (CoFeNiCrV-LH) nanosheets are rationally designed, which exhibit superior electrocatalytic activity and long-term durability towards the electrocatalytic oxygen evolution reaction, outperforming both CoFe layered double hydroxides and most previously reported transition-metal-based electrocatalysts. Comprehensive characterization and analysis reveal that the high-entropy effects play a significant role in forming the defect-rich, low-crystalline microstructures, along with large specific surface areas and optimized electronic configurations, thus enabling the boosted electrocatalytic performance. This electrochemical synthetic approach is generally applicable to the scalable synthesis of diverse HE-LH materials towards versatile promising applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Self-assembly of colloidal nanoparticles (NPs) into well-defined superstructures has been recognized as one of the most promising ways to fabricate rationally-designed functional materials for a variety of applications. Introducing hierarchical mesoporosity into NP superstructures will facilitate mass transport while simultaneously enhancing the accessibility of constituent NPs, which is of critical importance for widening their applications in catalysis and energy-related fields. Herein, we develop a colloidal co-assembly strategy to construct mesostructured, carbon-coated Co 0.5 Fe 2.5 O 4 NP superstructures (M-C@CFOSs), which show great promise as highly efficient electrocatalysts for the oxygen evolution reaction (OER). Specifically, organically-stabilized SiO 2 NPs are employed as both building blocks and sacrificial template, which co-assemble with Co 0.5 Fe 2.5 O 4 NPs to afford binary NP superstructures through a solvent drying process. M-C@CFOSs are obtainable after in situ ligand carbonization followed by the selective removal of SiO 2 NPs. The hierarchical mesoporous structure of M-C@CFOSs, combined with the conformal graphitic carbon coating derived from the native organic ligands, significantly improves their electrocatalytic performance as OER electrocatalysts when compared with nonporous Co 0.5 Fe 2.5 O 4 NP superstructures. This work establishes a new and facile approach for designing NP superstructures with hierarchical mesoporosity, which may find wide applications in energy storage and conversion. [ABSTRACT FROM AUTHOR]

The influence of perovskite components on the morphology, optical absorption and photovoltaic performances are systematically investigated. The results reveal that the surface and grain sizes of mixed perovskite film become rougher and larger with increasing FAI concentration. In the meanwhile, the formation of δ-FAPbI 3 is successfully inhibited. As a result, the efficiency of perovskite solar cells based on mixed absorbers is improved by about 27% compared to pristine MAI based perovskite devices. The absorption layer is a crucial factor for high-performance perovskite solar cells. In this work, the influence of the two components, methylammonium iodide (MAI) and formamidinium iodide (FAI) on the morphology, optical absorption and photovoltaic performances was systematically investigated. The results revealed that the surface morphologies of MAI/FAI based perovskite films were rougher, and the grain sizes became larger with increasing the FAI concentration. UV–Vis and photoluminescence spectra showed that there was a red shift with enhancing the FAI concentration. By the effective doping of FAI into the pristine MAI based perovskite film, the formation of a δ-FAPbI 3 was successfully inhibited. As a result, the power conversion efficiency (PCE) of the perovskite solar cells based on mixed absorption layers was improved by about 27% compared to the pristine MAI based perovskite device. [ABSTRACT FROM AUTHOR]

Abstract: Well-aligned CdS nanorod arrays (CdS NRs) with ∼100nm in diameter and ∼700nm in length were fabricated on FTO (fluorine-doped tin oxide) substrate by using glutathione as capping agents. The growth of CdS NRs was studied in details by exploring the roles of each active binding group in glutathione. The thiol group in glutathione plays an important role in forming a compact CdS nanocrystal film, upon which the nanorods grow subsequently via the synergetic effect of thiol and dicarboxyl groups in glutathione. The influence of surface passivation with glutathione on the photoelectrical property of CdS NRs was also tested. The results revealed that glutathione ligands encapsulated in the surfaces of CdS NRs act as insulating barriers between CdS NRs and solution, hindering charge transport. Hybrid photovoltaic cells of FTO/CdS NRs/P3HT (poly(3-hexylthiophene))/Au were then assembled. The performance of the photovoltaic devices was increased with increasing the length of the as-prepared CdS nanorods and further enhanced to the highest efficiency of 0.373% after the thermal sulfuration treatment. [Copyright &y& Elsevier]