With the world’s fossil fuels being finite in nature, an increasing interest focuses on the application of alternative renewable resources such as biomass. Biomass-derived platform chemicals with abundant functional groups have the potential to replace bulk chemicals for the production of value-added chemicals, fuels, and materials. The upgrading of these platform chemicals relies on the development of efficient catalytic systems. Hydrotalcite, with its wide compositional variety, tuneable anion-exchange capacity, and controlled acidity/basicity sites demonstrates great potential in the catalytic upgrading of biomass and the derived platform chemicals. The past decade has witnessed the emergence of research achievements on the development of efficient and robust hydrotalcite-derived metal catalysts and their applications in the upgrading of biomass or the derived platform chemicals. In this review, we aim to summarize the recent advances on the catalytic upgrading of biomass-derived platform chemicals (e.g., furfural, 5-hydroxymethylfurfural, levulinic acid, and glycerol) via hydrotalcite-derived metal catalysts. We also observed that the crucial role of using hydrotalcite-derived catalysts relies on their strong metal–support interactions. As a result, a section focusing on the discussion of the metal–support interactions of hydrotalcite-derived catalysts was provided.
CoTe@reduced graphene oxide (CoTe@rGO) electrode materials for supercapacitors were prepared by a one-step hydrothermal method in this paper. Compared with that of pure CoTe, the electrochemical performance of CoTe@rGO was significantly improved. The results showed that the optimal CoTe@rGO electrode material has a remarkably high specific capacitance of 810.6 F/g at a current density of 1 A/g. At 5 A/g, the synthesized material retained 77.2% of its initial capacitance even after 5000 charge/discharge cycles, thereby demonstrating good cycling stability. Moreover, even at a high current density of 20 A/g, the composite electrode retained 79.0% of its specific capacitance at 1 A/g, thus confirming its excellent rate performance. An asymmetric supercapacitor (ASC) with a wider potential window and higher energy density was assembled by using 3 M KOH as the electrolyte, the CoTe@rGO electrode as the positive electrode, and active carbon as the negative electrode. The operating voltage of the supercapacitor could be increased to 1.6 V, and its specific capacitance could reach 112.6 F/g at 1 A/g. The specific capacitance retention rate of the fabricated supercapacitor after 5000 charge/discharge cycles at 5 A/g was 87.1%, which confirms its excellent cycling stability. In addition, the ASC revealed a high energy density of 40.04 W·h/kg at a power density of 799.91 W/kg and a high power density of 4004.93 W/kg at an energy density of 33.43 W·h/kg. These results collectively show that CoTe@rGO materials have broad application prospects.
F-doping hard carbon (F–HC) was synthesized through a mild fluorination at temperature at relative low temperature as the potential anode for sodium-ion batteries (SIBs). The F-doping treatment to HC expands interlayer distance and creates some defects in the graphitic framework, which has the ability to improve Na+ storage capability through the intercalation and pore-filling process a simultaneously. In addition, the electrically conductive semi-ionic C–F bond in F–HC that can be adjusted by the fluorination temperature facilitates electron transport throughout the electrode. Therefore, F–HC exhibits higher specific capability and better cycling stability than pristine HC. Particularly, F–HC fluorinated at 100 °C (F–HC100) delivers the reversible capability of 343 mAh/g at 50 mAh/g, with the Coulombic efficiency of 78.13%, and the capacity retention remains as 95.81% after 100 cycles. Moreover, the specific capacity of F–HC100 returns to 340 mAh/g after the rate capability test demonstrates its stability even at high current density. The enhanced specific capacity of F–HC, especially at low-voltage region, has the great potential as the anode of SIBs with high energy density.
Black phosphorus has been recognized as a prospective candidate anode material for sodium-ion batteries (SIBs) due to its ultrahigh theoretical capacity of 2596 mA·h/g and high electric conductivity of ≈ 300 S/m. However, its large volume expansion and contraction during sodiation/desodiation lead to poor cycling stability. In this work, a BP/graphite nanoparticle/nitrogen-doped multiwalled carbon nanotubes (BP/G/CNTs) composite with a dual-carbon conductive network is successfully fabricated as a promising anode material for SIBs through a simple two-step mechanical milling process. The unique structure can mitigate the effect of volume changes and provide additional electron conduction pathways during cycles. Furthermore, the formation of P–O–C bonds helps maintain the intimate connection between phosphorus and carbon, thereby improving the cycling and rate performance. As a result, the BP/G/CNTs composite delivers a high initial Coulombic efficiency (89.6%) and a high specific capacity for SIBs (1791.3 mA·h/g after 100 cycles at 519.2 mA/g and 1665.2 mA·h/g after 100 cycles at 1298 mA/g). Based on these results, the integrated strategy of one- and two-dimensional carbon materials can guide other anode materials for SIBs.
It is difficult for solanum crops to grow continuously during winter in severe cold regions. Thus, a soil heating system for facility agriculture based on solar concentration technology was proposed, and a novel compound parabolic concentration photothermal and photoelectricity device (CTPV) equipped in the system was designed to address this problem. In accordance with the structure of the device, LightTools optical software was selected to analyze the variation trend of the light escape rate of the device with the different incident angles. On the basis of the calculation results, an experimental test system was used to investigate the relationship of the air temperature of the inlet and the outlet, total output power of the solar cells, and photothermal and photoelectricity efficiency of the device with the operation time during a sunny day. Research results reveal that the light escape rate of the device is 5.36% at an incidence angle of 12°. At a velocity of 1.5 m/s, the maximum air temperature of the outlet can reach 55.6 °C, and the total output power of the solar cells is 474.4 W. The variation of the total power of the solar cells is consistent with the simulation results. The maximum instantaneous heat collection and the maximum photothermal and photoelectricity efficiency of the device are 306 W and 60.4%, respectively, and the average efficiency is 44.9%. This study can serve as a reference for compound parabolic concentration technology applied for soil heating in facility agricultural soil heating systems.
Nickel–cobalt tellurides are deemed as promising electrode materials for energy storage devices due to their superior conductivity and theoretical specific capacitance. Here, NiCoTe2 was successfully fabricated on carbon cloth by facile electrodeposition and hydrothermal synthesis, which can directly serve as a binderless electrode. The NiCoTe2 with interconnected nanosheet arrays on a conductive carbon substrate showed a high specific capacitance (924 F/g at 1 A/g) and robust long-term cycling stability (89.6% retention after 5000 cycles). In addition, the assembled NiCoTe2//activiated carbon hybrid supercapacitor achieved a high energy and power density with a short charging time (42.26 Wh/kg at a power density of 760.96 W/kg). This work provides a novel idea to produce bimetallic nickel–cobalt telluride nanosheet array electrodes for high-performance hybrid supercapacitors.