Gold catalysts readily catalyze CO oxidation at subambient temperature, wherein moisture can influence the activity, typically with a volcano-shaped dependence. In this study, we examine moisture-enhanced CO oxidation over Au/BN. The room-temperature CO oxidation activity of Au/BN increases quickly with increasing moisture content up to 100% relative humidity (RH). In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and in situ UV–vis diffuse reflectance spectroscopy (UV-vis-DRS) demonstrate that mainly metallic gold is present on the h-BN support. Surface intermediates are found when moisture is fed together with CO and O2, attributable to *CO­(H2O) n and *OOH, respectively. These surface intermediates are reactive when counter-reactant is purged. Injection of isotope-labeled H2 18O demonstrates that OH from H2O takes part in the process of CO2 formation. The results of this study provide direct evidence showing moisture-enhanced CO adsorption, moisture-enhanced O2 adsorption, and their activation that can possibly lead to promotion of CO oxidation over the Au/BN catalyst.

An advanced magnetic biochar (MBC) was facilely prepared via one-pot FeCl3-activation of lotus seedpod. Simultaneous carbonization, activation, and magnetization formed magnetic Fe3O4 nanoparticles and nanowires over the biochar base. The specific surface area (SBET) and the total pore volume (Vtotal) of MBC were 349 m2/g and 0.31 cm3/g, which were 2.0-fold and 3.9-fold higher than those of biochar, respectively. In addition, the saturation magnetization of MBC reached 6.94 emu/g, which could facilitate its magnetic separation and recovery. In heterogeneous Fenton-like catalytic oxidation, 0.40 g/L MBC decolorized 100% Orange G and reduced 58% COD by 350 ppm H2O2 within 120 min. The degradation kinetics were calculated with different MBC samples and reactions followed pseudo-first-order kinetics with the highest rate constant of 0.034 min-1. Moreover, catalytic activity dropped by only 6.4% after four reuse cycles, with negligible iron leaching. Based on these results, MBC could be a low-cost, highly effective, and relatively stable catalyst for treating Orange G in wastewater.

In this research, magnetic porous carbon was directly synthesized through one-step pyrolysis of FeCl3 – lotus seedpod mixture. Properties of the obtained material were analysed by X-ray powder diffraction, SEM image, nitrogen adsorption isotherm and vibrating sample magnetometer. The results showed that magnetic Fe3O4 particles were successfully formed over material template in 1 hour. The magnetic porous carbon possessed the specific magnetization of 7.13 emu/g, high specific surface area of 288 m2/g and total pore volume of 0.18 cm3/g. The material was subsequently applied as a potential catalyst for Ponceau 4R degradation by H2O2. Parameters including pH, H2O2 concentration, and different types of catalysts were investigated. At pH 3, 200 ppm H2O2, and 0.40 g/L magnetic porous carbon, 83% Ponceau 4R 50 ppm was removed after 120 minutes treatment. Moreover, the catalyst powders were separated from the treated mixture easily by a magnet. Summarily, magnetic porous carbon can promise to be an efficient catalyst in decomposition of Ponceau 4R.

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