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Water splitting is an efficient strategy to produce purity hydrogen and convert intermittent electricity from renewable wind and solar sources. In this work, dense NiMoO4 micro-pillars arrays (MPAs) were in-situ grown on nickel foam (NF) through facile hydrothermal method, then the NiMoO4/NF were converted into NiMoO4–P/NF and NiFe/NiMoO4/NF via phosphating and electrodeposition method, respectively. The NiMoO4–P/NF electrode required small overpotentials of 34 mV@10 mA cm−2 and 130 mV@100 mA cm−2 for hydrogen evolution reaction (HER). The NiFe/NiMoO4/NF electrode exhibited excellent oxygen evolution reaction (OER) activity with overpotentials of 210 mV@10 mA cm−2 and 300 mV@100 mA cm−2. The overall water splitting using the anode-cathode couple of NiFe/NiMoO4/NF||NiMoO4–P/NF only consumes low voltages of 1.47 V@10 mA cm−2 for 100 h and 1.66 V@100 mA cm−2 for 50 h in 1 M KOH. The electronic modification and the well-designed hierarchical structure contribute the high energy-efficient and stabile overall water splitting.

Degradation of NO3− into harmless N2 is a significant challenge in the field of water treatment. In this work, 3D self-supported hierarchical electrode composed of ultra-thin Cu nanosheets-assembled micro-columns on porous nickel foam (Cu NSs/NF) was prepared by three steps, including electrodeposition of CuCl-Cu, thermal oxidation into CuCl-CuO and electrochemical reduction into Cu NSs. Benefitting from the advantages of large surface area and highly active interface as well as fast electron-transfer path, Cu NSs/NF exhibits the significant positive-shift of potential and higher current density than other Cu-based electrodes in the electrochemical reduction of NO3− (NO3−-ER). Not only that, an extremely high sensitivity of nitrate reduction response up to 11.23 mA mM−1 cm−2 was obtained by chronoamperometric test, which is much higher than those of previously reported works. Moreover, a conversion percentage of 99.7% for NO3−-ER was achieved on Cu NSs/NF cathode in NO3−-ER experiments. Finally, through the cathodic reduction of NO3− coupled with the anodic oxidation of Cl−, and the subsequent chemical reaction of NH4+ and ClO−, the highly efficient degradation of NO3− into N2 with selectivity as high as 97.2% was realized. This work provides a highly efficient Cu NSs/NF electrode and a promising way for degradation of NO3− into N2.

In order to investigate the cutting mechanical characteristics of Caragana korshinskii (C.k.) branches and explore the optimal combination of cutting parameters to support the subsequent equipment development, this paper explores the relationship between branch diameter D, average cutting speed v, wedge angle β, slip cutting angle α, cutting height h, cutting gap t, moisture content M and peak cutting force by using a homemade swing-cut branch cutting test bench with peak cutting force of branches as the target value under unsupported and supported cutting methods, respectively, through single-factor tests. Based on the single-factor test, v, β, α and t were selected as the test factors, and a multi-factor test was conducted with the peak cutting force as the target. Test result: The best combination of unsupported cutting in the range of multi-factor test is v for 3.315 m·s−1, β for 20°, α for 20°, when the peak cutting force is 95.690 N. Supported cutting multi-factor test range to get the best combination of v for 3.36 m·s−1, β for 20°, α for 20°, t for 1.38 mm, when the peak cutting force is 53.082 N. The errors of the predicted peak cutting force and the measured peak cutting force of the obtained model were 1.3% and 3.9%, respectively, which prove that the cutting parameters were optimized reliably. This research can provide a theoretical basis for subsequent development the C.k. harvesting equipment.

Hydrogen-motivated electrolysis of Na2CO3 for energy-saving production of NaOH and CO2/NaHCO3 is realized by the hydrogen oxidation reaction to insert proton into anolyte and the hydrogen evolution reaction to extract proton out of catholyte. Electrolytic voltage at 100 mA cm−2 is as low as 0.88 V; this voltage is only 35% of the voltage used in the traditional electrolysis.