Author
Danyun Xu
Bio: Danyun Xu is an academic researcher from Tianjin University. The author has contributed to research in topics: Catalysis & Self-healing hydrogels. The author has an hindex of 12, co-authored 17 publications receiving 629 citations.
Papers
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TL;DR: In this article, a simple strategy to synthesize the hierarchical MoS2/Ti3C2Tx hybrid by combining liquid nitrogen-freezing and subsequent annealing was reported.
Abstract: Developing highly efficient noble-metal-free electrocatalysts for hydrogen evolution reaction (HER) has attracted increasing attentions. Here, we report a simple strategy to synthesize the hierarchical “nanoroll” like MoS2/Ti3C2Tx hybrid by combining liquid nitrogen-freezing and subsequent annealing. The quick freezing of the Ti3C2Tx nanosheets and ammonium tetrathiomolybdate mixture causes a sudden change in the strain of Ti3C2Tx, which leads to an interesting “nanoroll” like hierarchical structure. After annealing at H2/Ar atmosphere, vertically aligned molybdenum sulfide (MoS2) crystallites are in situ formed in and on the nanoroll like Ti3C2Tx. Notably, this hierarchical MoS2/Ti3C2Tx hybrid exhibits excellent HER catalytic activity with a small onset overpotential of 30 mV, and a more than 25-fold increase in the exchange current density compared with MoS2 was observed.
195 citations
TL;DR: The preparation of 1-2 layer semiconducting WS2 nanosheets in a yield of 18-22 wt % by a modified LPE method that involves preintercalation with substoichometric quantities of n-butyllithium is reported.
Abstract: Monolayer WS2 has interesting properties as a direct bandgap semiconductor, photocatalyst, and electrocatalyst, but it is still a significant challenge to prepare this material in colloidal form by liquid-phase exfoliation (LPE). Here, we report the preparation of 1–2 layer semiconducting WS2 nanosheets in a yield of 18–22 wt % by a modified LPE method that involves preintercalation with substoichometric quantities of n-butyllithium. The exfoliated WS2 nanosheeets are n-type, have a bandgap of ∼1.78 eV, and act as a cocatalyst with CdS nanorods in photocatalytic hydrogen evolution using lactate as a sacrificial electron donor. Up to a 26-fold increase in H2 evolution rate was observed with WS2/CdS hybrids compared with their pure CdS counterpart, and an absorbed photon quantum yield (AQE) of >60% was measured with the optimized photocatalyst.
100 citations
TL;DR: In this paper, a 3D photoanode with exfoliated MoS2 nanosheets on TiO2 nanorod arrays (TiO2 NAs) was successfully fabricated by combining hydrothermal and drop-casting methods.
Abstract: A novel three-dimensional (3D) photoanode with exfoliated MoS2 nanosheets on TiO2 nanorod arrays (TiO2 NAs) was successfully fabricated by combining hydrothermal and drop-casting methods. The influences of the different phases (1T and 2H) of the MoS2 nanosheets on the photoelectrochemical (PEC) performances of such a TiO2 NAs/MoS2 3D system have been systematically investigated. Parallel experiments revealed that the TiO2 NAs/1T-MoS2 composite with optimized 1T-MoS2 loading exhibited the highest photoelectric conversion efficiency, which was about 440 and 93% higher than those of the TiO2 NAs and the TiO2 NAs/2H-MoS2 counterpart, respectively. The enhanced catalytic performances of the TiO2 NAs/1T-MoS2 composite can be attributed to the superior conductivity of 1T-MoS2 and the strong interaction between TiO2 NAs and 1T-MoS2. The photogenerated holes can therefore transfer from the TiO2 NAs to the 1T-MoS2, thus leading to enhanced charge separation efficiency.
96 citations
TL;DR: In this article, a simple strategy was proposed to controllably synthesize pure RuP and RuP2 and evaluate their HER performances in all pH range. But the performance of the RuPx in all HP range obviously improves as the phosphorus content decreases.
Abstract: Metal phosphides are promising efficient non-Pt electrocatalysts for hydrogen evolution reaction (HER). Herein, we report a simple strategy to controllably synthesize pure RuP and RuP2 and evaluate their HER performances in all pH range. Different from other transition metal phosphides, the HER performance of the RuPx in all pH range obviously improves as the phosphorus content decreases. By systematic research, it has been found that the RuP-475 with more Ru had much better conductivity and more catalytically active sites than the P rich RuP2-550. In addition, the RuP-475 exhibits excellent HER performance with small overpotential at a current density of 10 mA cm–2 (46, 47, 22 mV in pH 0, 7, and 14, respectively).
78 citations
TL;DR: A facile method to incorporate exfoliated Ti2C3Tx nanosheets in the PNIPAM network is reported, and the obtained MXene/PNIPAM composite hydrogel shows excellent photothermal properties, expanding the pure thermal-responsive property of the PnIPAM hydrogels.
Abstract: Poly(N-isopropylacrylamide) (PNIPAM) is broadly applicable in many fields due to its temperature-induced phase transition property. Herein, a facile method to incorporate exfoliated Ti2C3Tx nanosheets in the PNIPAM network is reported. Due to compatibility, stability and photothermal properties of the incorporated Ti2C3Tx nanosheets, the obtained MXene/PNIPAM composite hydrogel shows excellent photothermal properties, expanding the pure thermal-responsive property of the PNIPAM hydrogel. Based on the smart composite hydrogel, remote light-control of the microfluidic pipeline is also demonstrated.
62 citations
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TL;DR: In this article, the main advancements in overcoming the barriers accompanied by pure ZnO and the criteria for fabrication of effective visible-light-responsive (ZnO-based) photocatalysts are reviewed.
697 citations
TL;DR: The latest advances in the use of MoS2 nanosheets for important water-related environmental applications such as contaminant adsorption, photocatalysis, membrane-based separation, sensing, and disinfection are presented.
Abstract: In an era of graphene-based nanomaterials as the most widely studied two-dimensional (2D) materials for enhanced performance of devices and systems in numerous environmental applications, molybdenum disulfide (MoS2) nanosheets stand out as a promising alternative 2D material with many excellent physicochemical, biological, and mechanical properties that differ significantly from those of graphene-based nanomaterials, potentially leading to new environmental phenomena and novel applications. This Critical Review presents the latest advances in the use of MoS2 nanosheets for important water-related environmental applications such as contaminant adsorption, photocatalysis, membrane-based separation, sensing, and disinfection. Various methods for MoS2 nanosheet synthesis are examined, and their suitability for different environmental applications is discussed. The unique structure and properties of MoS2 nanosheets enabling exceptional environmental capabilities are compared with those of graphene-based nanoma...
570 citations
TL;DR: In this article, the state-of-the-art progress on MXene theory, materials synthesis techniques, morphology modifications, opto-electro-magnetic properties, and their applications are comprehensively discussed.
502 citations
TL;DR: This review presents a systematic review on the fabrication routes of ASCs followed by an overview of some new and effective characterization methods to precisely probe the atomic structure and discusses the challenges and opportunities on the further development of more selective, active, stable and less expensive ASCs.
Abstract: Electrocatalysis plays a central role in clean energy conversion, enabling a number of processes for future sustainable technologies. Atomic site electrocatalysts (ASCs), including single-atomic site catalysts (SASCs) and diatomic site catalysis (DASCs), are being pursued as economical alternatives to noble-metal-based catalysts for these reactions by virtue of their exceptionally high atom utilization efficiencies, well-defined active sites and high selectivities. In this review, we start from a systematic review on the fabrication routes of ASCs followed by an overview of some new and effective characterization methods to precisely probe the atomic structure. Then we give a comprehensive summary on the current advances in some typical clean energy reactions: water splitting, including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER); oxygen reduction reaction (ORR), including selective 4e- - ORR toward H2O/OH- and 2e- - ORR toward H2O2/HO2-; selective electrooxidation of formic acid, methanol and ethanol (FAOR, MOR and EOR). At the end of this paper, we present a brief conclusion, and discuss the challenges and opportunities on the further development of more selective, active, stable and less expensive ASCs.
487 citations
TL;DR: This review will first overview the emerging 2D materials and then offer a clear guideline of varied physical and chemical strategies for tuning their properties and assembly strategies of2D materials will also be included.
Abstract: Two-dimensional (2D) materials have attracted tremendous research interest since the breakthrough of graphene. Their unique optical, electronic, and mechanical properties hold great potential for harnessing them as key components in novel applications for electronics and optoelectronics. Their atomic thickness and exposed huge surface even make them highly designable and manipulable, leading to the extensive application potentials. What's more, after acquiring the qualification for being the candidate for next-generation devices, the assembly of 2D materials monomers into mass or ordered structure is also of great importance, which will determine their ultimate industrialization. By designing the monomers and regulating their assembling behavior, the exploration of 2D materials toward the next-generation circuits can be spectacularly achieved. In this review, we will first overview the emerging 2D materials and then offer a clear guideline of varied physical and chemical strategies for tuning their properties. Furthermore, assembly strategies of 2D materials will also be included. Finally, challenges and outlooks in this promising field are featured on the basis of its current progress.
390 citations