Pan CHEN,Jia-yan LIU,Ji-hua ZHAI,Yao-hui YANG,Wei SUN
n-octylphosphonic acid (OPA) was introduced as a novel collector for ilmenite flotation and its effectiveness was compared with the conventional chelating collector, benzohydroxamic acid (BHA). Micro-flotation tests demonstrated that OPA was a highly effective and selective collector for separating ilmenite from titanaugite over acidic conditions (optimal pH around 3), which was also supported by adsorption amount measurements. X-ray photoelectron spectroscopy (XPS) tests indicated that the chemisorption of OPA onto ilmenite surface was much stronger than that of BHA. Solution chemistry diagram analyses indicated that OPA could dissociate well at pH 3.0 and mostly exist in anion form. DFT calculations further confirmed that OPA was much easier to adsorb onto ilmenite surface with shorter bond length and lower adsorption energy in comparison with BHA. Therefore, OPA maintained good collecting ability and selectivity for ilmenite flotation in the strongly acidic pulp, providing valuable insights into new collector design and development.
Perovskite-based light-emitting diodes (PeLEDs) are arousing great interest as promising technology for next-generation displays due to their narrow emission linewidth, tunable emission wavelength, and high photoluminescence quantum yield. Due to the superiorities of the simple fabricating process and high efficiency, the in situ preparation of PeLEDs has attracted more attention. However, numerous defects are induced due to the ligand loss in the in situ fabrication of the perovskite film, which restricts the performance improvement of PeLEDs to a larger extent. Here, we introduce a dual ligand 2,2-diphenylethylamine bromide (DPEA-Br) in precursor solution and n-octylphosphonic acid (OPA) in antisolvent for in situ fabricating FAPbBr3 perovskite nanocrystals (PNCs). As a result, the OPA–FAPbBr3 PNC films demonstrate a higher crystallinity, a longer radiative lifetime, and an improved environmental stability, due to the synergistic effect of compensating ligands and passivating defects of OPA. Finally, we obtain a significantly enhanced device efficiency of a maximum luminance of 3273 cd m−2 and a current efficiency of 17.7 cd A−1, which are 12.5 times and 6.1 times higher than those of the control device, respectively. The ligand compensation method with OPA proposed in this work can provide a robust platform for achieving high-quality PNC films and highly efficient PeLEDs.
Aluminum metal has been regarded as a promising anode material for aqueous metal-air batteries. However, the stable cycling of Al anodes is challenging due to the severe parasitic corrosion of Al metal in alkaline electrolytes. Here, a novel additive, n -octylphosphonic acid (OPA), is introduced into the typical NaOH electrolyte system to improve the interfacial stability of Al anodes and thus promote high-performance Al-air batteries (AABs). Combining several experimental characterizations and theoretical calculation, it is proved that OPA molecules in an NaOH aqueous environment can modify the Al anode/electrolyte interface and alter the stacking of the discharge product. The electrolyte engineering is capable of anchoring dynamically to restrain side reactions through hydrogen bonds (H···O), homogenizing the dissolution of Al metal and avoiding precipitation agglomeration. As a proof of concept, AABs full cells with an electrolyte containing OPA achieve higher potential plateau and discharge capacity than those with a pure NaOH electrolyte. It paves a way to develop highly-efficient and eco-friendly electrolyte additive strategies for high-performance AABs devices and advance the current understanding of organic additive mechanisms in AABs.
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