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Gold and Bi-bearing parageneses are pivotal to understanding gold concentration and deposition processes. The large-scale Laozuoshan gold deposit is located in the Jiamusi Block, northeastern China, and has experienced complex mineralization processes with abundant gold and Bi-bearing minerals. However, the relationship between Bi-minerals and gold is unclear, preventing our understanding of the gold enrichment and precipitation mechanism in the Laozuoshan gold deposit. Optical microscope and SEM results show three stages of gold mineralization: pyrrhotite (Po-1) + arsenopyrite (Apy-1) + Bi-bearing minerals (Bis-1) + Au-1; arsenopyrite (Apy-2) + chlorite + Bi-bearing minerals (Bis-2) + Au-2; and arsenopyrite (Apy-3) + graphite + Bi-bearing minerals (Bis-3) + Au-3. The abundant amount of gold (Au-1~Au-3) is associated with Bi-bearing minerals (Bis-1~Bis-3), which coexist as inclusions and fill in fractures in these minerals. The mineral assemblages of arsenopyrite, Bi-minerals, and gold exhibit a clear As-Bi-Au mineralogy in the ores, and the ternary diagram of the chemical compositions of the Bi-minerals shows that Bi-minerals all fall in reducing regions, indicating that Bi-minerals are precipitated under reducing conditions. The gold compositions demonstrate a positive correlation (R2 = 0.58) between Au and Bi. Consequently, we propose that the gold experienced the ore-forming fluids concentration and further Bi-melts scavenging for the Laozuoshan gold deposit mineralization. The Bi collector model is essential in interpreting the high-grade gold in the Laozuoshan gold deposit, indicating that the geochemical anomalies observed with bismuth may be a critical potential exploration target for the high-grade gold deposits in the Jiamusi Block. [ABSTRACT FROM AUTHOR]

Achieving a colossal room‐temperature electrocaloric effect is essential for practical solid‐state refrigeration applications with low‐cost and high‐efficiency. Here, through the design of applying external stimuli (hydrostatic pressure and misfit strain), giant room‐temperature electrocaloric effects in the bulk and thin film of metal‐free organic perovskite [MDABCO](NH4)I3 are obtained by using a combination of thermodynamic calculations and phase–field simulations. Under the hydrostatic pressure of 1 GPa, there emerges excellent room‐temperature (300 K) electrocaloric performance with the temperature change (ΔT) of 8.41 K at 30 MV m−1 and electrocaloric strength (ΔT/ΔE) of 0.63 K m MV−1 at 10 MV m−1, respectively. The prominent electrocaloric effects of MDABCO(NH4)I3 may be related to its rapid change rates of free energy barrier height. Additionally, it can be found that some stripe domains and non‐180° domain walls form in the [MDABCO](NH4)I3 bulk, which is consistent with the experimental results. This work not only provides new insights into organic perovskite [MDABCO](NH4)I3, but also guides for further developing to realize remarkable room‐temperature electrocaloric cooling. [ABSTRACT FROM AUTHOR]

In this work, FeCo/N‐doped porous carbon nanosheets (FeCo/NPC) were in‐situ synthesised as bifunctional oxygen catalyst following a sodium chloride (NaCl) template‐assisted strategy. The results show that this strategy assists in generating a 3D interconnected carbon nanosheets network with hierarchical pores and a larger specific surface area through a stencil effect. X‐ray photoelectron spectroscopy (XPS) results show that the Fe 2p3/2 and Co 2p3/2 core‐level binding energy (BE) of the FeCo/NPC catalyst exhibits a positive shift compared to monometallic catalysts, which is associated with downshifts of the d‐band position of the metal by alloying and weakening of the interaction between oxygenic species and metal surfaces, thereby improving the catalytic activity. The FeCo/NPC catalyst shows excellent electrocatalytic activity for bothoxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline solution: a high onset potential of 0.92 V (vs. RHE), only 10 mV difference of half‐wave potential comparable with commercial Pt/C (20 wt%), a high current retention of 95.7 % after stability test of 20000 s for ORR and a potential of 1.68 V (vs. RHE) for OER at 10 mA ⋅ cm−2. The high catalytic performance of the FeCo/NPC catalyst and the simplicity of the synthesis method provide a possibility for its practical application in metal‐air batteries. Connect the dots: FeCo/N‐doped 3D interconnected porous carbon (FeCo/NPC) nanosheets are synthesized following a NaCl template‐assisted strategy in a one pot approach. The resulting FeCo/NPC electrocatalyst shows excellent catalytic activity and stability for both, the oxygen evolution reaction and the oxygen reduction reaction, demonstrating its promising potential for applications in metal‐air batteries. [ABSTRACT FROM AUTHOR]

A superior 3D architecture Ni foam/MgFe2O4 integrative electrode was firstly designed and synthesized via a simple hydrothermal method and subsequent calcination as a binder‐free anode for lithium‐ion batteries (LIBs). MgFe2O4 nanoparticles with diameter of about 60 nm interconnect with each other to form porous nanosheets and anchor on the Ni foam (N‐MFO). The 3D architectural design with superior conductivity and a strong skeleton structure not only provides fast kinetics, reduces the polarization and enhances the rate performance, but also buffers volume expansion and improves the cycle stability during the discharge/charge process. In addition, the interfacial lithium storage of the N‐MFO electrode promotes high lithium‐storage capacity, superior cycle stability and impressive rate capability. Even cycling at a current density of 5 A g−1 for 1000 cycles, the capacity remains stable at about 780 mAh g−1. Bright spark: A superior 3D architecture composed of a nickel foam/MgFe2O4 integrative electrode was designed and synthesized as the binder‐free electrode for lithium‐ion batteries. The electrode exhibits excellent cycle performance and impressive rate capability. [ABSTRACT FROM AUTHOR]

We investigated the polarization-switching pathway-dependent electrical transport behaviors in rhombohedral-phase BiFeO 3 thin films with point contact geometry. By combining conducting-atomic force microscopy and piezoelectric force microscopy, we simultaneously obtained current-voltage curves and the corresponding domain patterns before and after the polarization switching. The results indicate that for the (001)-oriented film, the abrupt current (due to polarization reversing) increases with the enhanced switching voltage for 109° and 180° switching events. More importantly, the abrupt current can be further improved in (110)- and (111)-oriented thin films, which benefits from the stronger modulation of the interfacial Schottky barrier by the enhanced out-of-plane polarization magnitude. The current on-off ratio obtained in a ∼20 nm thick (111)-oriented BiFeO 3 thin film at a readout voltage of ∼3 V exceeds (∼6 × 10 5 )%, which is close to the result from a previous report on ultrathin tetragonal BiFeO 3 thin films.