Remove humic acid from water quickly using only oxygen and sulfite at nickel cobalt spinel catalyst.

The typical refractory organic pollutant, humic acid (HA), causes many water and wastewater treatment obstacles. In this study, a novel method was proposed to degrade HA based on the low-temperature (<100 °C) catalytic air oxidation technology (LTCAO) using the NiCo-spinel (NCO) as a catalyst and the sulfite as a promoter. Sulfite enhanced the quantity of mineralized HA to 2.4 times that without sulfite assistance, and the removal rate of total organic carbon reached 93.1% within 60 min at 90 °C. HA gradually degrades into small organic molecules and is mineralized through interfacial reactions and radical paths. Sulfite plays a triple role in these reactions. Sulfite sulfonated HA destroyed its pseudomicellar structure, making HA easily oxidized. Sulfite also coordinated with NCO and promoted the internal electronic hopping conduction of NCO because of the fast electron transfer between SO32- and the h+sites, thus accelerating the electron transfer between HA and O2 mediated by NCO. In addition, the coordinated SO32- was activated to form the radical ∙SO3-, which strengthened the oxidation of HA. This study supports a simple and green method for efficiently cleaning water and wastewater rich in HA.

Sol-Gel Prepared Spinel HTLs for Assembling 20% Efficiency Perovskite Solar Cell in Air Without Using Anti-Solvent and Toxic Solvent.

Low-temperature sol-gel prepared ZnCo2 O4 spinel-based thin films are developed as high-performance hole transporting layer (HTL) for coating perovskite film (NA-Psk) from the basic MAPbI3 /ACN/CH3 NH2 solution in air without using anti-solvent. Inverted PSC based on 2 mole% (vs Zn) Cu2+ doped ZnCo2 O4 (2%Cu@ZnCo2 O4 ) HTL and NA-Psk absorber exhibit the maximum power conversion efficiency (PCE) of 20.0% with no current hysteresis while the cell based on ZnCo2 O4 and PEDOT:PSS HTL (using NA-Psk absorber) achieves the PCE of 15.79% and 12.3% with a current hysteresis index of 9.8% and 32.4%, respectively. Without encapsulation, PSCs based on 2%Cu@ZnCo2 O4 , ZnCo2 O4 , and PEDOT:PSS HTLs maintain 90%, 77%, and 12%, respectively of the original efficiency by standing in ambient atmosphere (temperature: 20-25 °C, RH:30%-40%) for 1800 h. Large area (10 cm × 10 cm substrate) perovskite mini-module (PSM) with PCE over 15% is also demonstrated by using sol-gel prepared 2%Cu@ZnCo2 O4 HTL. The poor photovoltaic performance of PEDOT:PSS HTL is due to the basic MAPbI3 /ACN/CH3 NH2 solution will deprotonate the acidic PEDOT:PSS to reduce its conductivity whereas ZnCo2 O4 HTL are not affected by basic perovskite precursor solution.

Manganese-Cobalt Based Spinel Coatings Processed by Electrophoretic Deposition Method: The Influence of Sintering on Degradation Issues of Solid Oxide Cell Oxygen Electrodes at 750 °C.

This paper seeks to examine how the Mn-Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn-Co spinel coating is processed on Crofer 22 APU substrates by electrophoretic deposition, and subsequently sintered, following both the one-step and two-step sintering, in order to obtain significantly different densification levels. The electrochemical characterization is performed on anode-supported cells with an LSCF cathode. The cells were aged prior to the electrochemical characterization in contact with the spinel-coated Crofer 22 APU at 750 °C for 250 h. Current-voltage and impedance spectra of the cells were measured after the exposure with the interconnect. Post-mortem analysis of the interconnect and the cell was carried out, in order to assess the Cr retention capability of coatings with different microstructures.

Copper-Doped Cobalt Spinel Electrocatalysts Supported on Activated Carbon for Hydrogen Evolution Reaction.

The development of electrocatalysts based on the doping of copper over cobalt spinel supported on a microporous activated carbon has been studied. Both copper-cobalt and cobalt spinel nanoparticles were synthesized using a silica-template method. Hybrid materials consisting of an activated carbon (AC), cobalt oxide (Co3O4), and copper-doped cobalt oxide (CuCo2O4) nanoparticles, were obtained by dry mixing technique and evaluated as electrocatalysts in alkaline media for hydrogen evolution reaction. Physical mixtures containing 5, 10, and 20 wt.% of Co3O4 or CuCo2O4 with a highly microporous activated carbon were prepared and characterized by XRD, TEM, XPS, physical adsorption of gases, and electrochemical techniques. The electrochemical tests revealed that the electrodes containing copper as the dopant cation result in a lower overpotential and higher current density for the hydrogen evolution reaction.