Constructing Z-scheme photocatalysts is an effective approach to enhance the conversion efficiency of solar to chemical energy. Herein, W
O
/g-C
N
heterostructures have been synthesized by growing W
...O
ultrathin nanowires on g-C
N
nanosheets via a convenient solvothermal process. Various characterizations were performed on the materials to understand the structure-performance relationship. The photocatalytic properties of the W
O
/g-C
N
heterostructures were evaluated by the two oxidation reactions, phenol degradation and oxidative NC coupling of benzylamines, under a simulated sunlight (360 ≤ λ ≤ 780 nm). With tuning the W
O
/g-C
N
mass ratio, the optimal photocatalyst of W
O
(30)/g-C
N
containing 30 wt% W
O
nanowires exhibited the highest activity in both the photocatalytic reactions. The generations and contributions of the active species in the photocatalytic reactions were identified by electron spin resonance (ESR) spectra and active-species-eliminating experiments. Accordingly, the photocatalytic mechanism of W
O
/g-C
N
heterostructures has been expounded based on the direct Z-scheme electron transfer between the two semiconductors as well as the synergistic actions of active sites on W
O
nanowires and g-C
N
nanosheets. This work demonstrates a rational paradigm to construct 1D/2D semiconductor heterostructures and provides further insights into Z-scheme photocatalytic mechanism for boosting solar-driven pollutant degradation and organic transformation.
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•Providing a strategy to synthesize CuS-NPC.•CuS-NPC improves specific capacity and electronic conductivity.
In this work, an electrode composite (CuS-NPC) for supercapacitors was ...synthesized by loading hexagonal nano-sheeted copper sulfide onto porous carbon through a solvothermal reaction using thiourea and copper acetate as the sulfur and copper sources, respectively. The synergistic effect of nanoscale copper sulfide sheet and hierarchical pore structure of porous carbon with high surface area achieves excellent capacitive performance in electrochemical reactions. CuS-NPC exhibited a large specific capacitance of 1298.7F g−1 at current density of 0.5 A/g and 766.3F g−1 at current density of 10 A/g, revealing that the electrode composite of copper sulfide and porous carbon have a great prospect as a supercapacitor electrode material.
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A selenoantimonate (C4H14N2)0.5Cu2SbSe3 (1) (C4H12N2 = 1, 4-butanediamine) was synthesized by solvothermal synthesis using 1, 4-butanediamine as solvent. By single-crystal X-ray ...diffraction, compound 1 has a two-dimensional (2-D) layered structure composed of a protonated organic amine (C4H14N2)0.5+ and an anionic layer Cu2SbSe3- containing the 6-membered rings (6-MR) Cu2SbSe3 and the 10-membered rings (10-MR) Cu3Sb2Se5. Solid-state UV-diffuse reflectance analysis showed that 1 has a band gap value of 1.85 eV, indicating its potential semiconducting properties. This paper studied the photodegradation properties of selenoantimonate containing the transition metal Cu for the first time, and found that its degradation rate methylene blue (MB) was 68.5 %. In addition, a series of characterizations were also performed.
2-D iodoplumbate hybrids Hhmta2(hmta)2Pb4I10·2DMF·H2O (1) and mhmta4Pb3I10·H2O (2) were prepared under mild solvothermal conditions. Compounds 1 and 2 were photosensitive to visible light, and ...exhibited strong photocurrent responses with current densities of 7.71 μA·cm−2 and 10.68 μA·cm−2, respectively. They showed high catalytic activity form the photodegradation of crystal violet, with degradation ratios of 96.5 % over 1, and 97.8 % over 2.
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The solvothermal reaction of PbI2, KI and HI in a H2O/DMF mixed solution in the presence of the coordination functional template hexamethylenetetramine (hmta) produced a 2-D iodoplumbate hybrid Hhmta2(hmta)2Pb4I10·2DMF·H2O (1). The hmta molecule was methylated by MeOH to form a mhmta+ (mhmta+ = N-methylhexamethylenetetramine) cation in the same reaction in H2O/MeOH solution. The mhmta+ cation lost its coordination function, leading to the formation of the 2-D iodoplumbate hybrid mhmta4Pb3I10·H2O (2). In 1, the PbI5 units are interconnected via edge- and face-sharing into a 1-D chain Pb4I10n2n−. The Pb4I10n2n− chains are linked by μ-hmta bridging ligand to form a 2-D (hmta)2Pb4I10n2n− layer. In 2, three PbI6 octahedra are joined by face-sharing to form a trinuclear Pb3I12 SBU. The Pb3I12 SBUs are connected into a 2-D Pb3I10n4n− anionic layer by corner- sharing. Compounds 1 and 2 exhibited rapid photocurrent responses with steady current densities of 7.71 μA·cm−2 and 10.68 μA·cm−2, respectively. These compounds exhibited high catalytic activity in the photodegradation of crystal violet with degradation rates of 96.5 % over 1 and 97.8 % over 2.
Support-free nanostructured LiBH4 is succesfully synthesized by a single-pot solvothermal process, which enables 12 wt% reversible hydrogen storage at redcued temperatures and pressures.
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•Neat LiBH4 nanoparticles of 50–60 nm in size are successfully prepared.•Nano-LiBH4 enables 12 wt% of reversible H capacity at moderate conditions.•Hydrogen release starts from ∼190 °C and re-absorbs at 165 °C and 100 bar.•The foaming is prevented due to the formation of LiH and B before melting.•The close contact between LiH and B is crucial for good reversibility.
Lithium borohydride (LiBH4) exhibits poor hydrogen storage reversibility because of phase separation between LiH and B due to foaming during thermal dehydrogenation. Herein, we report that by synthesizing nanostructured LiBH4 without any supports, the foaming and phase separation can be effectively suppressed, and consequently, the hydrogen storage reversibility of LiBH4 can be considerably improved. Using a facile single-pot solvothermal approach, a hierarchical porous nanostructured LiBH4 composed of 50–60 nm-sized primary nanoparticles is synthesized. The resulting neat nano-LiBH4 reversibly desorbs and absorbs approximately 12 wt% of H at 400 °C and under 100 bar H2. The superior hydrogen storage performance is attributed to the effective inhibition of foaming upon heating. The formation of LiH and B prior to melting, which can be associated with the largely reduced particle sizes and porous agglomeration structure, plays a crucial role in suppressing foaming. Our findings offer a new strategy for the preparation of nanoscaled freestanding borohydrides, and also important insights into the development of highly reversible metal borohydrides for hydrogen storage applications.
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This review summarized recent research progresses on the in-situ synthesis of molecular magnetorefrigerant materials derived from organic ligands, metal ions and templates generated ...in-situ.
•In-situ synthetic strategy for the construction of molecular magnetorefrigerant materials has been reviewed.•Molecular magnetorefrigerant materials with ligands, metal ions and templates formed in-situ have been illustrated.•The influencing factors toward magnetocaloric effect of the molecular magnetorefrigerants are detail discussed.
Zero-dimensional cluster complexes and coordination polymers for magnetic refrigeration have attracted great interest in the last decade. In-situ synthesis is a widely-used method to assemble various molecular magnetorefrigerant materials derived from different types of ligands. This review focuses mainly on the synthesis, structure and magnetochemistry of molecular magnetorefrigerant materials via in-situ synthesis, with an emphasis on in-situ generation of ligands, metal ions and templates. The first section gives a brief discussion on molecular magnetorefrigerants and some important principles obtained from magneto–structural correlation. The in-situ synthetic strategy will also be referred to and elucidated in this part. The next three sections give overviews of the main results obtained by our group and other groups in recent years, which are, in-situ generated ligands, metal ions and templates in the synthesis of molecular magnetorefrigerant materials. Finally, the conclusions and perspectives of molecular magnetorefrigerant materials will be presented. Some of the trends could provide new insights for the further development of this promising area.
Two-dimensional (2D) molybdenum sulfide (MoS2) is an attractive noble-metal-free electrocatalyst for hydrogen evolution (HER) in acids. Tremendous effort has been made to engineer MoS2 catalysts with ...either more active sites or higher conductivity to enhance their HER activity. However, little attention has been paid to synergistically structural and electronic modulations of MoS2. Herein, 2D hydrogenated graphene (HG) is introduced into MoS2 ultrathin nanosheets for the construction of a highly efficient and stable catalyst for HER. Owing to synergistic modulations of both structural and electronic benefits to MoS2 nanosheets via HG support, such a catalyst has improved conductivity, more accessible catalytic active sites, and moderate hydrogen adsorption energy. On the optimized MoS2/HG hybrid catalyst, HER occurs with an overpotential of 124 mV at 10 mA cm–2, a Tafel slope of 41 mV dec–1, and a stable durability for 24 h continuous operation at 30 mA cm–2 without observable fading. The high performance of the optimized MoS2/HG hybrid catalyst for HER was interpreted with density functional theory calculations. The simulation results reveal that the introduction of HG modulates the electronic structure of MoS2 to increase the number of active sites and simultaneously optimizes the hydrogen adsorption energy at S-edge atoms, eventually promoting HER activity. This study thus provides a strategy to design and develop high-performance HER electrocatalysts by employing different 2D materials.
Ultralong cobalt sulfide (CoS1.097) nanotube networks are synthesized by a simple one-step solvothermal method without any surfactant or template. A possible formation mechanism for the growth ...processes is proposed. Owing to the hollow structure and large specific area, the novel CoS1.097 materials present outstanding electrochemical properties. Electrochemical measurements for supercapacitors show that the as-prepared ultralong CoS1.097 nanotube networks exhibit high specific capacity, good capacity retention, and excellent Coulombic efficiency.
