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We use MOFs material as precursor to synthesize carbon based two‐dimensional (2D) materials loaded with In2S3−In2O3 (In−S−O) nanoparticles. The In−S−O nanoparticles have exhibited Janus architecture composed of two compounds with different crystal structures that are combined in‐plane on 2D carbon material surface. The excellent properties of this in‐plane Janus material include 2D nanoarchitecture and its Janus properties formed by combining two different crystal structures. It has exhibited excellent electrochemical performances due to its abundant electrochemical active sites and large specific surface area. According to experiments, the electron transfer number of the material for two‐electron oxygen reduction is about 2.4, and the hydrogen peroxide yield is 32 mg/h cm2. In the further test of liquid flow electrolytic cell, the yield can reach up to 172 mg/h cm2. [ABSTRACT FROM AUTHOR]

It has been long believed that the FeMoS structure, where Fe is bonded with S, plays a pivotal role as a biomimetic catalyst for electrochemical nitrogen (N2) fixation. Nevertheless, the structure of Fe bonded to heavier analogues (Se or Te) has never been explored for N2 electrofixation. Here, we theoretically predict the electronic structure of FeMo(Se, Te) composed of tri‐coordinated Fe species with open shells for binding with Se, which forms a joint electron pool for promoting N2 activation. Guided by this interesting prediction, we then demonstrate a two‐step procedure to synthesize such structures, which display remarkable N2 electrofixation activities with an ammonia yield of 72.54 μg h−1 mg−1 and a Faradic efficiency of 51.67 % that are more than three times of the FeMoS counterpart. Further mechanism studies have been conducted by density function theory (DFT) simulations. This work provides new clues for designing versatile electrocatalytic materials for large‐scale industrialization. [ABSTRACT FROM AUTHOR]

Vacancy engineering is an effective strategy to manipulate the electronic structure of electrocatalysts to improve their performance, but few reports focus on phosphorus vacancies (Pv). Herein, the creation of Pv in metal phosphides and investigation of their role in alkaline electrocatalytic hydrogen evolution reaction (HER) is presented. The Pv‐modified catalyst requires a minimum onset potential of 0 mV vs. RHE, a small overpotential of 27.7 mV to achieve 10 mA cm−2 geometric current density and a Tafel slope of 30.88 mV dec−1, even outperforms the Pt/C benchmark (32.7 mV@10 mA cm−2 and 30.90 mV dec−1). This catalyst also displays superior stability up to 504 hours without any decay. Experimental analysis and density functional theory calculations suggest Pv can weaken the hybridization of Ni 3d and P 2p orbitals, enrich the electron density of Ni and P atoms nearby Pv, and facilitate H* desorption process, contributing to outstanding HER activity and facile kinetics. [ABSTRACT FROM AUTHOR]

A universal technique has been proposed to sort two-dimensional (2D) sub-nanometer thin crystals (manganese dioxide MnO2 and molybdenum disulfide MoS2) according to their lateral dimensions. This technique is based on tuning the zeta potential of their aqueous dispersions which induces the selective sedimentation of large-sized 2D crystals and leaves the small-sized counterparts in suspension. The electrocatalytic properties of as-obtained 2D ultrathin crystals are strongly dependent on their lateral size. As a proof-of-concept study, the small-sized MnO2 nanocrystals were tested as the electrocatalysts for the urea-oxidation reaction (UOR), which showed outstanding performance in both half reaction and full electrolytic cell. A mechanism study reveals the enhanced performance is associated with the remarkable structural properties of MnO2 including ultrathin (ca. 0.95 nm), laterally small-sized (50-200 nm), and highly exposed active centers. [ABSTRACT FROM AUTHOR]

This work reports a universal dissolution-recrystallization method to synthesize two-dimensional (2D) conductive metal-organic framework (MOF) arrays. The MOF arrays have exhibited excellent structural characteristics for electrochemical reactions, including ultrathin architecture, metallic conductivity, and hierarchical macro-/micro-porosity. Particularly, 2D nickel, iron-MOF arrays act as bifunctional electrocatalysts for water splitting, which deliver a current density of 500 mA cm−2 at an overpotential of 305 mV for anodic oxygen evolution reaction (OER), 359 mV for hydrogen evolution reaction (HER), and ~640 mV for overall reactions. The electrode also shows prolonged stability against bulk water splitting (up to 20 h at 500 mA cm−2). In addition, the water splitting system has been further coupled with commercial solar cells to simulate natural water photolysis, demonstrating a high solar-to-hydrogen efficiency of 17.69%. Mechanism study thorough density function theory (DFT) computations shows strong synergistic effect between Ni and Fe active sites that can reduce the Gibbs energy barrier of hydroxyl dissociation step (OH* → O*) during OER and H* desorption step during HER simultaneously. These promising results open up enormous opportunities of designing versatile low-dimensional conductive MOF architectures for renewable energy applications. [Display omitted] • A general method is reported for synthesizing metallic 2D MOF array. • The material has demonstrated excellent structural advantages for electrocatalysis. • The electrode has shown excellent activities for OER, HER and water splitting. • The solar-to-hydrogen efficiency of the system is as high as 17.69%. • DFT calculations reveal the strong synergistic effect inside the material. [ABSTRACT FROM AUTHOR]