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This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials and Interfaces, copyright © 2022 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsami.2c02675. Metallic 1T-phase MoS2 exhibits superior hydrogen evolution reaction (HER) performance than natural 2H-phase MoS2 owing to its higher electrical conductivity and abundance of active sites. However, the reported 1T-MoS2 catalysts usually suffer from extreme instability, which results in quick phase transformation at ambient conditions. Herein, we present a facile approach to engineer the phase of MoS2 by introducing intercalated hydrazine. Interestingly, the as-synthesized 1T-dominant MoS2 sample demonstrates excellent ambient stability without noticeable degradation for 3 months. Additionally, the 1T-dominant MoS2 exhibits superior electrical conductivity (~700 times higher than that of 2H-MoS2) and improved electrochemical catalytic performance (current density ~12 times larger than that of 2H-MoS2 at an overpotential of 300 mV vs the reversible hydrogen electrode, RHE). Through experimental characterizations and density functional theory (DFT) calculation, we conclude that the stabilization of the metallic phase could be attributed to the electron donation from hydrazine molecules to the adjacent Mo atoms. The phase control strategy in this work provides a guideline to develop other highly efficient and stable two-dimensional (2D) electrocatalysts.

Mesoporous carbon nitrides with C3 N5 and C3 N6 stoichiometries created a new momentum in the field of organic metal-free semiconductors owing to their unique band structures and high basicity. Here, we report on the preparation of a novel graphitic microporous carbon nitride with a tetrazine based chemical structure and the composition of C3 N5.4 using ultra-stable Y zeolite as the template and aminoguanidine hydrochloride, a high nitrogen-containing molecule, as the CN precursor. Spectroscopic characterization and density functional theory calculations reveal that the prepared material exhibits a new molecular structure, which comprises two tetrazines and one triazine rings in the unit cell and is thermodynamically stable. The resultant carbon nitride shows an outstanding surface area of 130.4 m2 g-1 and demonstrates excellent CO2 adsorption per unit surface area of 47.54 μmol m-2 , which is due to the existence of abundant free NH2 groups, basic sites and microporosity. The material also exhibits highly selective sensing over water molecules (151.1 mmol g-1 ) and aliphatic hydrocarbons due to its unique microporous structure with a high amount of hydrophilic nitrogen moieties and recognizing ability towards small molecules.

In order to overcome the current energy and environment crisis caused by fossil fuels depletion and greenhouse gas emission, it is indispensable to introduce new, eco-friendly, high-performance materials into energy conversion and storage applications. 2D transition metal oxides (TMOs) are regarded as the promising candidates due to their excellent electrochemical properties. However, their innate poor electronic conductivity greatly restricts their applications in energy conversion and storage. This review discusses and summarizes the developed strategies to overcome the limitation through surface modification including defect engineering, heteroatom incorporation and interlayer doping, as well as hybridization with conductive materials. In addition, a detailed summary of their synthesis and applications in supercapacitors, lithium ion batteries and electrocatalysis is included. Finally, future prospective such as opportunities and challenges is discussed for the successful implementation of 2D TMOs in the field of energy applications.

Hydrogen evolution reaction (HER) by effective catalysts has been extensively investigated as a promising way to produce H2 as a clean and sustainable energy source. Previous studies have identified Pt as one of the most efficient catalysts due to the fast kinetics and the moderate hydrogen binding energy, while the high-cost of Pt restrains the practical applications. In this research, we present a hydrothermal method to fabricate the hybrid of nanoscale noble metals incorporated in the earth-abundant material MoS2. The results indicate that incorporation of a small amount of Au and Pt strongly enhances the HER performance compared with pure MoS2, which attributes to the enhanced electrical charge transfer, increased active sites, and reduced resistance. Especially, the electrocatalytic performance of the as-synthesized 5% weight loading Pt-MoS2 is comparable with the commercial 10% Pt/C catalyst, with a low overpotential of 103 mV vs. RHE at the current density of 10 mA cm−2 and Tafel slope of 56 mV dec–1. The sample also exhibits excellent durability, and the low amount of noble metal usage could reduce the cost to a large extent, making it more practical to be applied in hydrogen generation. The strategy to control the particle size with the various morphologies of the supporting material MoS2 may also be useful to develop other noble metal–based catalysts.

Colossal saturation magnetization and giant coercivity are realized in MoS2 single crystals doped with Nb and/or Co using an ion implantation method. Magnetic measurements have demonstrated that co...

Mesoporous carbon nitrides with C

Colossal saturation magnetization and giant coercivity are realized in MoS

Shape-controlled MoS2 has been grown directly on a silicon substrate, for the first time, with the use of a facile hydrothermal synthesis approach. The growth morphology is dependent on the substra...

Electrocatalysis plays a major role in the development of clean and sustainable energies. For efficient hydrogen evolution reaction (HER) in water splitting, active, robust, and cost-effective catalysts are highly desired. Here, we present a facile approach to fabricate 1T-phase dominant V-doped MoS2 nanosheets which can be easily grown on carbon paper at a large scale. The 5 at.% V-doped MoS2 nanosheets achieve excellent catalytic performance, showing more than 10-fold increase of current density compared with 2H MoS2 and a surprisingly low onset potential of 102 mV vs reversible hydrogen electrode (RHE). Moreover, it exhibits good catalytical stability in both acidic and alkaline solutions. The remarkable HER performance mainly attributes to the synergistic effects of the modified structure of MoS2 with enhanced active sites, increased electrical conductivity, optimised energy level and near-zero Gibbs free energy of hydrogen binding. This work may shed light on achieving highly efficient electrocatalysts toward practical applications.