Search

To address the accuracy requirements of initial alignment of high-precision inertial navigation systems (INSs), gravity disturbance compensation for INSs based on a spherical harmonic model is investigated herein. First, the horizontal component of gravity disturbance at an alignment point is calculated using the high-resolution Earth Gravity Model EIGEN-6C4 and then compensated to the initial alignment. Subsequently, the self-alignment algorithm of solidified coordinate frame is used to derive the misalignment angle equation of gravity disturbance affecting the initial alignment. Meanwhile, the coupling relationship between the measurement error of an inertial unit and the gravity disturbance is simulated and analyzed. Finally, a laser strapdown inertial navigation system experiment is performed. The simulation result shows that the pitch angle, roll angle, and heading angle errors reduced by $27.41^{\prime \prime }$ , $- 0.37^{\prime \prime }$ , and $6.72^{\prime \prime }$ , respectively, after the gravity disturbance compensation. Experiment result shows that the alignment performance after compensation has been improved and the heading angle error is reduced by $6.76^{\prime \prime }$ . The simulations and experiments results validate the theoretical analysis.

Currently, designing and preparing low-cost and high-efficiency electrocatalysts still remains of huge impediment for direct ethanol fuel cells (DEFCs). In this work, by leveraging the unique superiority of Co3[Co(CN)6]2 (Prussian blue analogues, PBA) precursor, we used Pt4+ to replace partial dispersed Co2+ in Co3[Co(CN)6]2 and a metal–organic framework (MOF) derived PtCo electrocatalyst (MD-PtCo/C) was successfully fabricated. Notably, as-obtained MD-PtCo/C (Pt, 0.9532 wt.%) electrocatalyst achieves high utilization rate of ultra-low Pt load and exhibits favorable electrocatalytic performance with lower onset potential, higher EOR activity, less activation energy (Ea) value and better stability compared to commercial Pt/C for ethanol oxidation reaction (EOR). Moreover, the consequence of concentrations (KOH, C2H5OH) and temperatures on electrocatalytic activity of EOR have also been studied. This study would be supportive of developing highly active and low-cost electrocatalysts for other catalytic applications.

The development of efficient electrocatalyst is very important for hydrazine oxidation reaction (HzOR). Here, a series of phosphatized pseudo-core-shell electrocatalysts (Fe@Cu-P/C) is prepared by replacement method and phosphatized calcination process. The optimal HzOR electrocatalyst is explored by studying different phosphatized temperatures. The 300 °C-treated Fe@Cu-P/C presents higher electrocatalytic activity (45 mA·mg−1FeCu) and shows better stability (93.5%) compared to others. Additionally, to better understand the HzOR process, the effects of different concentrations, scan rates and temperatures are also investigated. The good HzOR performance of Fe@Cu-P/C electrocatalyst attributes to its combined advantages of Cu-P shell and Fe-core as well as strong synergistic interaction between them.

The search for non-precious-metal catalysts with low cost, high activity and stability to substitute Pt in oxygen reduction reaction (ORR) attracts tremendous attention. Herein, novel ORR electrocatalysts of cerium species embedded N-doped carbon (CENC) materials are prepared by the chemical oxidative polymerization and pyrolysis methods, using polyaniline-coated cerium organic complex (Ce(TTA)3Phen) as the precursor. The experimental results have revealed that the electrocatalytic activity of the obtained electrocatalysts for ORR is affected by the pyrolysis temperature. Remarkably, the as-prepared CENC-1000 exhibits a good catalytic activity in terms of limiting current density, onset potential and half wave potential, as well as superior tolerance to methanol crossover for ORR as comparable to commercial Pt/C in alkaline media. The high performance is attributed to the introduction of nitrogen active sites and Ce active species (generated from the pyrolysis of CENC precursor), which endow CENC-1000 with enhanced electrocatalytic activity. This approach makes CENC-1000 a promising candidate as cathode catalyst in renewable energy conversion devices.

An amorphous ultra-dispersed electrocatalyst, AU-Pt/PMC, is successfully synthesized via severe etching process for glycerol oxidation reaction. What's appealing, it presents amorphous structure with ultra-small Pt clusters (0.36 nm) anchoring on nitrogen functionalized carbon support. Notably, the AU-Pt/PMC electrocatalyst takes on 5.1 times the activity and 24.3 times the stability compared with commercial Pt/C for glycerol oxidation reaction. The impressive electrocatalytic performance originates from the unique amorphous ultra-dispersed structure, as well as the superimposed effect between Pt clusters and Strong Metal-Support Interactions.

Although core-shell structure is favored by many applications, preparing it with green way is rarely been reported. Herein, a core-shell structured Cu@Pd-CS nanocomposite is greenly fabricated utilizing a natural chitosan and applied to glucose detection. As-obtained Cu@Pd-CS nanoparticles were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (XRD). When applied to glucose detection, the Cu@Pd-CS exhibits good stability, sensitivity and anti-interference. Moreover, it has a good linear relationship in glucose concentrations range of 0.1−1 mM with the sensitivity of 1.53 μA mM−1 cm−2 and 1−10 mM with the sensitivity of 23.00 μA mM−1 cm−2. This work proves the practicability of building metal-based core-shell structure nanoparticles with green resources and glucose detection application.

Recently, advanced nitrogen-containing carbon materials create a huge opportunity for developing efficient catalysts, and show great potential in zinc-air batteries (ZABs). In this study, YF3 doped nitrogen-containing carbon (YF3@NC) electrocatalyst is prepared using m-phenylenediamine as nitrogen and carbon sources. Yttrium chloride, ammonium fluoride and l -arginine are used as Y source, F source and assistant, respectively. Spherical YF3 precursor is obtained through a facile arginine-assisted hydrothermal method, which is then coated with nitrogen-containing carbon and pyrolyzed at high temperature to fabricate YF3@NC. It exhibits a positive onset potential (0.943 V), half-wave potential (0.836 V), high current density and good cycling stability (10 h degradation: 13%). When YF3@NC is applied as air cathode electrode in ZABs, the obtained battery has a high open circuit potential (1.478 V) and peak power density (75 mW cm−2). This approach makes YF3@NC to be a promising candidate as cathode catalyst in ZABs in the future.

The development of economical and efficient bifunctional electrocatalyst is quite important for rechargeable zinc-air batteries (ZABs). Herein, a prussian blue analogue (Co3[Co(CN)6]2, PBA) derived PBA-Pd-Co/C composite electrocatalyst with good oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalytic properties was developed via using bits of PdCl2 to modify carbonized Co3[Co(CN)6]2. The results show that as-prepared PBA-Pd-Co/C possesses good positive ORR half-wave potential (0.82 V), feasible OER potential (1.73 V) of 10 mA cm−2, minor ORR and OER Tafel slopes (53.61 and 57.07 mV dec−1), as well as high ZAB power density (138.8 mW cm−2) and good galvanostatic charge-discharge cycling stability. These good performances of PBA-Pd-Co/C are mainly ascribed to the good synergistic effect of Co and Pd nanoparticles (NPs) composited in PBA-derived nitrogen-enriched graphite carbon. This work would be supportive of expanding other low-cost and high-efficiency PBA-derived electrocatalysts in the future.

Seeking high activity non-noble-metal electrocatalysts is essential to develop high performance hydrazine fuel cells. In this study, an electrocatalyst of phosphorus doped nickel-cobalt alloy is fabricated for hydrazine oxidation reaction (HzOR). A series of physical and electrochemistry results show that, among as-prepared four electrocatalysts, the NiCoP/C has the lowest Tafel slope, the highest current density, the longest durability and relative low apparent activation energy for HzOR. Moreover, the influences of KOH and N2H4 concentrations, scanning speeds as well as the temperatures as to NiCoP/C electrocatalyst towards HzOR are also investigated. Besides, electrochemical impedance test exhibits as-obtained NiCoP/C owes good charge transfer kinetics. This work would stimulate more study to explore P doped non-noble metal electrocatalyst in the future.