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Il-MnP1, a short-type manganese peroxidase from Irpex lacteus F17, can oxidize some substrates in the absence of Mn2+, but the catalysis was much lower than in the presence of Mn2+. Here, we report a mutant R70V/E166A of Il-MnP1 with some unique properties, which possessed clearly higher catalysis for the decolorization of anthraquinone and azo dyes in the absence of Mn2+ than that of Il-MnP1. Importantly, the optimum pH of R70V/E166A for decolorization of anthraquinone dyes (Reactive Blue 19, RB19) was 6.5, and the mutant achieved high decolorization activities in the range of pH 4.0–7.0, whereas Il-MnP1 only showed decolorization for RB19 at pH 3.5–4.0. In addition, the optimum H2O2 concentration of R70V/E166A for RB19 decolorization was eight times that of Il-MnP1 and the H2O2 stability has improved 1.4 times compared with Il-MnP1. Furthermore, Mn2+ competitively inhibited the oxidation of RB19 by R70V/E166A, explaining the higher catalytic activity of the mutant R70V/E166A in the absence of Mn2+. Molecular docking results suggested that RB19 binds to the distal side of the heme plane in mutant R70V/E166A, which extended from the heme δ-side to the heme γ-side, and close to the mutated residues of R70V and E166A, whereas RB19 could not access the heme pocket of Il-MnP1 due to the steric hindrance of the side-chain group of Arg 70. Thus, this study constructed a useful mutant R70V/E166A and analyzed its higher Mn2+-independent activity, which is very important for better understanding the Mn2+-independent catalytic mechanism for short manganese peroxidases. Key points: •The mutant R70V/E166A of atypical MnP1 of I. lacteus F17 shows unique catalytic properties. •At pH 6.5, the R70V/E166A had a strong ability to decolorize anthraquinone dyes in the absence of Mn2+. •The binding sites of Reactive Blue 19 in mutant R70V/E166A were elucidated. [ABSTRACT FROM AUTHOR]

The morphologies of molybdenum carbide catalysts were designed by elaborately selecting organic carbon sources. Based on the scanning electron microscopy (SEM) images and Brunauer-Emmett-Teller (BET) surface area data, it is found that the structure and surface area of Mo x C y catalysts can be adjusted by selecting different organic carbon sources. Wire-like Mo x C y , nanosheet-like Mo x C y and rod-like Mo x C y catalysts were obtained by using aniline and p-phenylenediamin (pPd), 4-chloro-o-phenylenediamin (4CloPd), and o-phenylenediamin (oPd) as the carbon sources, respectively, and the nanosheet-like Mo x C y showed a relatively high surface area of 30.3 m 2 g −1 . Furthermore, the crystal structure of Mo x C y was found to be controlled by the organic carbon source. Notably, α-Mo x C y nanosheets prepared by using 4CloPd showed the best catalytic performance, in which the formic acid conversion approached 100% with a low CO selectivity when the reaction temperature was higher than 250 °C. [ABSTRACT FROM AUTHOR]

In this study, various metal nanoparticles (Ni, Co, Mg, Cu, Ag) were doped on the nanosheet-like Mo x C y prepared by using 4-Chloro-o-phenylenediamin (4CloPd) as the carbon source for the production of hydrogen by the decomposition of formic acid. It is found that the doping of metal on Mo x C y promoted the catalytic activity greatly. Among them, Ag and Mg doped Mo x C y catalysts exhibited much higher catalytic activity than others. Moreover, Mg doped MoC 1−x catalyst showed much lower CO production than Ag doped one. The performance of Mg doped MoC 1−x catalysts with different Mg loading amounts was investigated. It is found that Mg 1.0 Mo 99.0 C 1−x had the highest formic acid decomposition performance with a high conversion (above 90% at 200 °C), a low CO production (<10% at 200 °C) and a long-term stability. [ABSTRACT FROM AUTHOR]

• MoCo 2 O 4 decorating PbO 2 composite electrode was prepared through chemical bath deposition and electrodeposition. • Active particles of MnCo 2 O 4 made the composite shows optimal OER catalytic activity. • 3D-Ti/α-PbO 2 /β-PbO 2 -MnCo 2 O 4 composite materials exhibits more than 140 h stability at 50 mA⋅m−2 in 0.5 M H 2 SO 4. Developing a promising catalyst with both improved activity and robust durability for the oxygen evolution (OER) in an acidic electrolyte is extremely desirable. Here we constructed a novel MnCo 2 O 4 decorating PbO 2 electrode (3D-Ti/α-PbO 2 /β-PbO 2 -MnCo 2 O 4) with a sandwich-like structure via a successive co-precipitation and co-electrodeposition onto porous titanium (3D-Ti) support. The experimental results indicated that the introduction of porous titanium is essential for achieving a unique porous structure architecture. In addition, the adoption of MnCo 2 O 4 increased the contact area with electrolyte due to the large BET surface area of 144.06 cm2 g−1. Consequently, the synthesized 3D-Ti/α-PbO 2 /β-PbO 2 -MnCo 2 O 4 composite electrode exhibited a low overpotential of 379 and 453 mV at 10 and 50 mA cm−2, respectively, as well as a minor Tafel slope of 133 mV per decade in 0.5 M H 2 SO 4 solution. Furthermore, 3D-Ti/α-PbO 2 /β-PbO 2 -MnCo 2 O 4 presents robust durability, keeping steady for more than 140 h at 50 mA cm−2 and without observable performance degradation, which is superior to many reported state-of-the-art non-precious OER catalysts. This route is for creating and synthesizing non-precious and superior performance catalysts for electrolysis and beyond. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction kinetics in industrial zinc electrowinning is sluggish, resulting in low electrocatalytic activity and substantial energy expenditure (about one-third of energy was wasted due to the strong polarization effect). Herein, the paper described a core-shell structured MnCo 2 O 4.5 @C modified PbO 2 electrode through the pyrolysis and co-electrodeposition as a promising candidate for zinc electrowinning. As a result, the obtained Pb-0.2%Ag/ α -PbO 2 / β -PbO 2 -MnCo 2 O 4.5 @C composite electrode showed a sandwich-like structure, where Pb-0.2%Ag as a core, α -PbO 2 as a mid-layer, and β -PbO 2 -MnCo 2 O 4.5 @C served as an electrocatalytic layer. It also possessed improved OER catalytic activity, only required 680 mV to achieve a current density of 50 mA cm−2 and a Tafel slope of 216.04 mV dec−1 in an acidic solution containing 50 g L−1 Zn2+ and 150 g L−1 H 2 SO 4. The current efficiency increased by 0.7% and the cell voltage reduced by 360 mV as compared to a conventional Pb-0.76%Ag alloy electrode, leading to a remarkable energy-consumption reduction of 283.5 kW h for producing per ton metallic zinc. Furthermore, Pb-0.2%Ag/ α -PbO 2 / β -PbO 2 -MnCo 2 O 4.5 @C exhibited a prolonged service life, which worked about 44 h under an ultra-high current density of 2 A cm−2. Hence, this paper provides the strategy to design and construct non-precious, high-performance catalyst for electrolysis and other applications. [Display omitted] • MoCo 2 O 4.5 @C modifying PbO 2 composite electrode was prepared through pyrosis-annealing and electrodeposition. • The overpotential at 50 mA cm−2 of composite electrode was decreased by 353 mV as compared with Pb-0.76%Ag alloy. • The composite electrode had a long service life of 44 h when tested at 2 A cm−2. • As compared to Pb-0.76%Ag alloy, the energy consumption of composite electrode for one-ton zinc was lowered by 283.5 kW h. [ABSTRACT FROM AUTHOR]

SO 4 2 − / ZrO 2 -carbon nanotubes (CNTs) were prepared through direct precipitation using ZrOCl 2 ·8H 2 O and H 2 SO 4 as raw materials and CNTs as support. The structure of composite samples was characterized through X-ray diffraction, scanning electron microscopy, energy-dispersive spectrometry, and Fourier-transform infrared spectroscopy. Results show that CNTs may provide large surface areas and ZrO 2 tetragonal was closely coated on CNTs surface. This catalyst was used to synthesize acetophenone ethylene glycol ketal. Factors influencing the synthesis of ketalization were also discussed and optimum reaction conditions were confirmed. Experimental results show that the yield of acetophenone ethylene glycol ketal was approximately 98.5% under optimum reaction conditions. [ABSTRACT FROM AUTHOR]

S 2 O 8 2− /TiO 2 –exfoliated graphite (EG) solid acid catalysts were prepared by a sol–gel method using Ti(OCH 2 CH 2 CH 2 CH 3 ) 4 and (NH 4 ) 2 S 2 O 8 as raw materials, as well as EG as support. The structure of the composite samples was characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive spectrometry, and Fourier-transform infrared spectroscopy. The results demonstrate TiO 2 anatase to be closely coated on the surface of exfoliated graphite. The effects of calcination temperature on the acidity, texture, and catalytic performance of S 2 O 8 2− /TiO 2 –EG solid acid catalysts were further studied. Factors influencing the synthesis of acetalation were discussed, and the optimum reaction conditions were confirmed. Experimental results show that the yield of benzaldehyde glycol acetal was about 98.8% under the following conditions: molar ratio of benzaldehyde to glycol of 1:1.5, catalyst quantity of 0.5% of feedstock, and reaction time of 50 min. [ABSTRACT FROM AUTHOR]

In nanowire catalytic growth, the catalyst particles usually remain at the tip of as-grown nanowires, which can be utilized to prepare matchstick-like heterostructures at the nanoscale. Based on this feature and a solution-phase catalytic growth route, we herein report the synthesis of Ag 2 Se–ZnSe matchstick-like hetero-nanorods, consisting of Ag 2 Se head and ZnSe rod-like stem. Three different kinds of silver sources, including Ag(0), Ag 2 S, and Ag 2 Se, are selected as initial seeds for growing ZnSe crystalline nanowire/rods. By comparison with the case of Ag(0) or Ag 2 Se, the use of Ag 2 S nanoparticles, which alter the chemical composition of catalytic particles and convert to Ag 2 Se catalyst after adding Se precursor (SeO 2 ), is highly effective for the formation of uniform Ag 2 Se–ZnSe hetero-nanorods. The reason for this result may be attributed to a synergistic effect between the size of catalyst particles and the chemical conversion of Ag 2 S to Ag 2 Se. [ABSTRACT FROM AUTHOR]