Rapid synthesis of ultrathin 2D materials through liquid-nitrogen and microwave treatments

Metal-free two-dimensional (2D) materials have manifested fascinating properties and promising applications. But it has been a long-standing challenge to seek a universal, scalable and powerful strategy to produce 2D materials. Herein, we demonstrate a new universal and rapid method to exfoliate bulk layered materials into ultrathin 2D structures through liquid-nitrogen and microwave treatments.This study was supported by the National Natural Science Foundation of China (21776118 and 21676128), the China Postdoctoral Science Foundation (2017M621654), the Key Laboratory of Tropical Medicinal Plant Chemistry of Ministry of Education-Hainan Normal University (rdyw2018002), the Natural Science Foundation of Jiangsu Province (BK20180870), a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions, the High-tech Research Key Laboratory of Zhenjiang (SS2018002) and the high performance computing platform of Jiangsu University

Designing all-solid-state Z-Scheme 2D g-C3N4/Bi2WO6 for improved photocatalysis and photocatalytic mechanism insight

Bi2WO6 was modified by two-dimensional g-C3N4 (2D g-C3N4) via a hydrothermal method. The structure, morphology, optical and electronic properties were investigated by multiple techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy spectra (XPS), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Ultraviolet-visible diffuse reflection spectroscopy (DRS), photocurrent and electrochemical impedance spectroscopy (EIS), electron spin resonance (ESR), respectively. Rhodamine B (RhB) was used as the target organic pollutant to research the photocatalytic performance of as-prepared composites. The Bi2WO6/2D g-C3N4 exhibited a remarkable improvement compared with the pure Bi2WO6. The enhanced photocatalytic activity was because the photogenerated electrons and holes can quickly separate by Z-Scheme passageway in composites. The photocatalytic mechanism was also researched in detail through ESR analysis. Keywords: All-solid-state, Z-Scheme photocatalyst, 2D g-C3N4, Bi2WO6, Photocatalysi

Metallic 1T-TiS2 nanodots anchored on a 2D graphitic C3N4 nanosheet nanostructure with high electron transfer capability for enhanced photocatalytic performance

Photocatalysis is one of the most promising technologies for solar energy conversion. With the development of photocatalysis technology, the creation of low-dimensional structure photocatalysts with improved properties becomes more and more important. Metallic 1T-TiS2 nanodots with a low-dimensional structure were introduced into environmentally friendly two-dimensional g-C3N4 (2D-C3N4) nanosheets by a solvothermal method. It was found that the ultrathin TiS2 nanodots were uniformly anchored on the surface of the 2D-C3N4. The effective suppression of electron–hole recombination was realized due to the addition of the intrinsic metallic property of 1T-TiS2 in the prepared nanocomposite. The 5 wt% TiS2/2D-C3N4 nanocomposite exhibited the best photocatalytic performance and the degradation rate towards RhB was ca. 95% in 70 min, which showed an improvement of ca. 30% in comparison with 2D-C3N4. The results indicate that the obtained TiS2/2D-C3N4 nanocomposite is a promising photocatalyst for practical applications

Modulating built-in electric field via variable oxygen affinity for robust hydrogen evolution reaction in neutral media

Work function strongly impacts the surficial charge distribution, especially for metal-support electrocatalysts when a built-in electric field (BEF) is constructed. Therefore, studying the correlation between work function and BEF is crucial for understanding the intrinsic reaction mechanism. Herein, we present a Pt@CoOx electrocatalyst with a large work function difference (ΔΦ) and strong BEF, which shows outstanding hydrogen evolution activity in a neutral medium with a 4.5-fold mass activity higher than 20 % Pt/C. Both experimental and theoretical results confirm the interfacial charge redistribution induced by the strong BEF, thus subtly optimizing hydrogen and hydroxide adsorption energy. This work not only provides fresh insights into the neutral hydrogen evolution mechanism but also proposes new design principles toward efficient electrocatalysts for hydrogen production in a neutral medium.Agency for Science, Technology and Research (A*STAR)This work was financially supported by the Research Grants Council of Hong Kong (Poly U253009/18P) and the Hong Kong Polytechnic University (1-ZVGH). H.J.F. thanks the financial support from Agency for Science, Technology, and Research (A*STAR), Singapore by AME Individual Research Grants (A1983c0026)

Highly Efficient Visible-Light-Driven Schottky Catalyst MoN/2D g‑C₃N₄ for Hydrogen Production and Organic Pollutants Degradation

Charge separation efficiency is vital both in photocatalytic hydrogen production and pollutants degradation, which can be enhanced by loading cocatalysts. Unfortunately, the vast majority of high active and stable cocatalysts is noble-metal (such as platinum), which greatly impedes the commercialization of photocatalysis technology. In this work, we reported a non-noble-metal Schottky catalyst MoN/2D g-C₃N₄ based on metal–semiconductor junction principles. MoN can serve as the acceptor and transporter of photogenerated electrons. For photocatalytic performance, the best one achieved much higher efficiency for hydrogen (H₂) generation (265.1 times) and Rh B degradation (1.4 times) over bare g-C₃N₄ due to the improved charge separation and transportation. The advantages of MoN can be summarized as (i) non-noble-metal; (ii) superior conductivity; and (iii) abundant adsorption and active sites