We report the first use of polymeric carbon nitride (CN) for the catalytic selective oxidation of HS. The as-prepared CN with unique ultrathin "nanomeshes" structure exhibits excellent HS conversion and high S selectivity. In particular, the CN nanomesh also displays better durability in the desulfurization reaction than traditional catalysts, such as carbon- and iron-based materials.

CeO2-based catalysts are potentially suitable for H2S-selective oxidation, but their practical application is limited due to the problem of sulfate formation. Herein, we report a facile citric acid-assisted hydrothermal process for the fabrication of porous Fe-doped CeO2 with flower-like morphology that can drastically promote the catalytic activities of CeO2 with high durability. Among the synthesized catalysts, the one with well-defined (110) and (100) planes is highly active for H2S-selective oxidation with H2S conversion and sulfur selectivity of almost 100% at 220 °C, superior to most of the reported Ce-based catalysts. Meanwhile, outstanding catalytic stability is achieved because the presence of Fe ions alleviates ceria deactivation due to sulfation. The results of systematic investigation prove that the doping of Fe not only raises the density of oxygen vacancies but also promotes the redox ability and oxygen activity of the catalyst. We conducted in situ DRIFTS (diffuse reflection infrared Fourier transform spectroscopy) experiments and density functional theory (DFT) calculations to disclose the reaction mechanism of H2S oxidation. The derived insights are important for the design of efficient ceria-related catalysts for practical applications.

A series of graphitic carbon nitride (CN) in the form of nanosheets with porous structure have been prepared through thermal treatment of bulk CN in air. Compared with the bulk counterpart, the as-generated holey CN nanosheets are larger in specific surface area. Endowed with more active sites and enhanced mass transport ability, the latter display catalytic performance substantially superior to the former, exhibiting higher H2S conversion and S selectivity in the oxidation of H2S to S. Moreover, the CN nanosheets show much better durability than traditional catalysts. It is envisaged that the strategy is a general technique that can be extended to produce porous CN nanosheets from other nitrogen-rich precursors, as well as to prepare other 2D carbon-based materials for potential applications.

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Developing NH 3 separation technology with high efficiency is very meaningful for the advancement of the NH 3 synthesis process. In this work, a new class of deep eutectic solvents (DESs) were designed by pairing N,N,N′,N′-tetramethyl-1,3-propanediamine dihydrochloride ([TMPDA]Cl 2 ) with phenol (PhOH) at the molar ratios of 1:3∼7. [TMPDA]Cl 2 + PhOH DESs have multiple weak-acidic groups and viscosities of as low as 48.1 cP at 298.2 K. They also exhibit excellent performance for the separation of NH 3 , showing not only efficient and selective but also reversible absorption of NH 3 . Especially, the solubilities of NH 3 in [TMPDA]Cl 2 + PhOH DESs at low pressures can reach 4.49 mol/kg of NH 3 at 298.2 K and 13.3 kPa, being superior to those of most of the DESs and ILs reported in the literature. The mechanism of NH 3 absorption was further elucidated by quantum chemistry calculations and 1 H NMR spectra. It is validated that the efficient absorption of NH 3 in DESs origins from the strong interaction of multiple weak-acidic groups of DESs with NH 3 .

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In this work, the role of citric acid (CA) in preparing CoMo/Al 2 O 3 catalyst was investigated from aqueous impregnation solution to catalytic active site formation by laser Raman, UV−vis, in situ IR and mass spectrometry characterizations. COS and CO were employed as probe molecules to illustrate the formation of active site during and after catalyst sulfidation, respectively. Citric acid mainly coordinates with Mo, resulting in the presence of Mo−CA complex, which consequently enlarge the temperature window of MoS 2 formation. Parallels between in situ IR and activity testing suggest that citric acid addition increases the concentration of CoMoS active site without significantly changing its intrinsic activity. It is concluded that the essential role of CA in preparing CoMo/Al 2 O 3 catalyst is mainly ascribed to a tuning effect on the 2D morphology of MoS 2 slabs, resulting in MoS 2 exposes more S-edge to accommodate a cobalt atom to form more CoMoS sites.

A new adsorbate-mediated strategy was developed to enhance the metal−support interaction of Cu/CeO 2 , aiming to improve its catalytic activity and sintering resistance in the water−gas shift (WGS) reaction. By treating Cu/CeO 2 in a 20CO 2 /2H 2 gas mixture for the formation of surface HCO n (n = 2, 3), there was significant enhancement of the interaction between CeO 2 and Cu. The HCO n adsorbate was removed through calcination in an O 2 /Ar atmosphere at 400 °C for 6 h. The as-obtained Cu/CeO 2 catalyst was compared with the untreated counterpart in the WGS reaction. It was observed that CO conversion at 350 °C was 86% and 47%, respectively, over the two catalysts. The superiority of the former is attributed to the enhanced interaction between Cu and CeO 2 . In a run of 15 h at 400 °C, the treated catalyst showed no obvious sign of deactivation.