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The thermal conditions of soil are important in practical agricultural production. The characteristics of heat flux, moisture content, thermal conductivity, and other soil parameters vary with temperature. This study uses VADOSE/W to create a model of heat transmission between soil and atmosphere, simulating daily changes in soil temperature using sand mulching. By using the published data to verify the model, the results show that the fitting effect is good and the reliability of the model is verified. We also used this model to determine the temporal and spatial distributions of soil temperature, temperature differences, and a temperature gradient for sand mulching and bare soil during the growing season of spring wheat. These results indicated that the sand mulching preserved heat at night. The difference in temperature at each depth and the temperature gradient became negative with the gradual increase in solar altitude. The difference in soil temperature at each depth and the temperature gradient tended to become positive by 22:00. These results indicated that the sand mulch effectively maintained the soil temperature in the morning and night during the growing season and impeded the transfer of heat at mid-day. This study provides a new method for determining the transfer of heat in sand-mulched soil, which can guide the effective regulation of soil temperature.

Fine regulation of the interface phase and electronic structure is crucial for the hydrogen evolution reaction (HER) in low-cost heterogeneous catalysts. Herein, we have successfully synthesized MoS2/CoS2 hetero-nanostructures with an abundant 1T-MoS2 phase on a cobalt metal–organic framework (MOF), which show superior HER activity and stability with quite low overpotentials of 37 and 51 mV at 10 mA cm−2, and small Tafel slopes of 46 and 45 mV dec−1 in alkaline and acidic media, respectively, outperforming most of the recently reported Mo-based catalysts. Only 261 mV overpotential and 1.53 V are required to drive oxygen evolution and overall water splitting in alkaline media. It is suggested that the interface-assisted phase transition is activated by electron and Co injections. The outstanding electrocatalytic performance originates from the porous structure, metallic conductivity and refined phase modulation synergistic with interfacial chemistry. Theoretical calculations show that the interfacial Co sites are activated for optimal hydrogen adsorption and water dissociation. Our work provides new ideas for the development of MOF-derived electrocatalysts for applications in energy-related fields. [ABSTRACT FROM AUTHOR]

The multiple strategy design is crucial for enhancing the efficiency of nonprecious electrocatalysts in hydrogen evolution reaction (HER). In this work, we successfully synthesized N, P-codoped MoS 2 nanosheets as highly efficient catalysts by integrating doping effects and phase engineering using a porous metal-organic framework (MOF) template. The electrocatalysts exhibit excellent bifunctional activity and stability in alkaline media. The N, P codoping induces electron redistribution to enhance conductivity and promote the intrinsic activity of the electrocatalysts. It optimizes the H* adsorption free energy and the dissociative adsorption energy, resulting in significant enhancement of HER activity. Moreover, the porous MOF structure exposes a large number of electrochemically active sites and facilitates the diffusion of ions and gases, which improve charge transfer efficiency and structural stability. Specifically, at a current density of 10 mA cm -2 , the overpotential of the HER is only 32 mV, with a Tafel slope of 47 mV dec -1 and Faradaic efficiency as high as 98.51% (at 100 mA cm -2 ). Only a 338 mV overpotential is required to achieve a current density of 50 mA cm -2 for oxygen evolution reaction (OER), and a potential of 1.49 V (at 10 mA cm -2 ) is sufficient to drive overall water splitting. Further experimental measurements and first-principles calculations evidence that the exceptional performance is primarily attributed to the dual functionality of N and P dopants, which not only activate additional S sites but also initialize the phase transition of 2H to 1T-MoS 2 to facilitate the rapid charge transfer. Through in-depth exploration of the combined design of multiple strategies for efficient catalysts, our work paves a new way for the development of future efficient nonprecious metal catalysts.